Nephrolithiasis

Definition

Nephrolithiasis is the presence or formation of a stone within the kidney or urinary collecting system; the terms kidney stone disease, renal stone disease, urinary stone disease, and urolithiasis are commonly used as overlapping clinical descriptors. The literature supplied here uses “nephrolithiasis,” “kidney stone disease,” and “stone disease” in this broad sense, while distinguishing the anatomical location and clinical context when relevant. ^{[1]A1c[2]D5[8]D5[231]D}

The condition should be described as a disease process rather than solely as an imaging finding. Contemporary research identifies unresolved questions concerning mechanisms of stone formation and retention, the clinical importance of stone composition, and the significance of distinct formation patterns and associated pathological features. ^[8]D5 Accordingly, a complete nomenclature should specify, where known, the stone’s location, composition, burden, associated obstruction or infection, metabolic context, and whether the stone is present, passed, treated, or not confirmed at intervention. ^{[1]A1c[8]D5[230]D}

Anatomical and clinical classification

Anatomically, stones may be classified as renal, ureteral, or upper-tract urinary stones. The term “upper tract urinary stone disease” is used in population-based surgical research to identify stones involving the kidney or ureter. ^[230]D Renal stones may be further described by collecting-system location, such as renal pelvis or calyceal location, when imaging or endoscopy establishes the site; the supplied evidence emphasizes that modern endoscopes and micro-computed tomography can improve characterization of stone structure and location. ^[8]D5

Clinically, classification should distinguish: (1) an observed or suspected stone; (2) a retained stone; (3) a passed stone; (4) a stone treated during an intervention; and (5) a presumed stone that is not found. A “negative ureteroscopy” specifically means ureteroscopy performed with the intention of removing a kidney or ureteral stone but during which no stone is removed; this may occur because the stone has already passed or because the presumed stone lies outside the collecting system. ^[230]D

Disease severity can also be described by stone burden and complexity, although the supplied references do not establish a universal numerical threshold for these categories. Complex renal stone disease is a recognized indication context for percutaneous nephrolithotomy, and mini-percutaneous nephrolithotomy has been studied in adults with nephrolithiasis and chronic kidney disease stage 3 or higher. ^[227] This renal-function category describes the patient context and should not be mistaken for a stone-size or anatomical classification. ^[227]

Composition and metabolic classification

Stone composition is a central classification axis. The consensus literature specifically addresses idiopathic calcium nephrolithiasis, metabolic diagnosis, medical prevention, and systemic manifestations, indicating that calcium stone disease should be classified alongside its metabolic phenotype rather than treated as a purely local urological disorder. ^[1]A1c Where stone analysis and metabolic evaluation are available, nomenclature should identify the composition and relevant metabolic abnormality; when they are unavailable, the stone should be labeled as composition unknown rather than assigned a presumed composition. ^[1]A1c[8]D5

The available references do not provide sufficient detail to reproduce a complete composition taxonomy or validated biochemical thresholds. Therefore, terms such as “calcium stone,” “metabolic stone former,” or “idiopathic calcium nephrolithiasis” should be used only when supported by stone analysis, clinical evaluation, or the applicable diagnostic criteria. ^[1]A1c

Imaging, endoscopic, and computational nomenclature

Detection and classification may be based on imaging, endoscopy, or stone analysis. Ultrasound is used as a first-line diagnostic modality in many clinical settings but is limited by sensitivity and operator dependence. ^[2]D5 Artificial-intelligence and deep-learning systems have been investigated for ultrasound-based stone detection, classification, prediction of complications or outcomes, and procedural guidance; the evidence is heterogeneous, so algorithmic labels should not replace the underlying clinical, anatomical, and compositional description. ^[2]D5

Modern endoscopes provide higher-definition visualization, while micro-computed tomography is described as an optimal technique for assessing stone structure. ^[8]D5 The Endockscope represents a lower-cost smartphone-, lens-, and light-emitting-diode-based alternative to conventional endoscopic imaging; its evaluation compared image quality and diagnostic capability with standard endoscopic systems in cadaveric procedures, not in a clinical outcomes study. ^[7]D5 These technologies describe methods of observation or characterization and do not constitute independent disease classifications. ^[7]D5[8]D5

Procedural and outcome terminology

Treatment-related nomenclature should be kept separate from disease classification. The principal procedural terms represented in the supplied literature include ureteroscopy, extracorporeal shock-wave lithotripsy, percutaneous nephrolithotomy, and mini-percutaneous nephrolithotomy. ^{[227][229]D[230]D} Trends in renal access for percutaneous nephrolithotomy have been studied according to whether access was obtained de novo by urologists or by another provider, demonstrating that procedural terminology may encode workflow and provider roles rather than stone phenotype. ^[229]D

Postoperative complications should be classified independently using a validated complication system when reported. The Clavien classification is a five-grade system used to subdivide surgical complications, as demonstrated in a study of laparoscopic pyeloplasty. ^[4]C4 It is an outcome-severity classification and should not be used to classify stone composition, location, or baseline nephrolithiasis complexity. ^[4]C4

Administrative and epidemiological studies may define kidney stone disease using diagnostic and procedure codes. Recent population analyses have identified kidney-stone-related inpatient episodes and procedures using ICD-10 and national procedure classifications, whereas such coding does not necessarily provide composition, imaging appearance, or metabolic phenotype. ^[231]D Patient-facing terminology should also be interpreted cautiously because online kidney-stone resources vary in credibility, readability, and reliability. ^[3]C4

Overview and natural history

Nephrolithiasis results from the interaction of urinary supersaturation, crystal nucleation and growth, crystal aggregation, retention within the kidney, and renal tubular or interstitial injury. The available updated evidence emphasizes that stone disease is biologically heterogeneous: metabolic, genetic, environmental, inflammatory, obstructive, and urinary-tract factors may converge on calcium oxalate crystallization and tissue damage. ^{[238] [37]C4 [242]} Although many asymptomatic stones remain stable, others enlarge or subsequently cause pain, obstruction, infection, or require intervention, supporting an individualized approach to observation versus active treatment. ^[14]A1a

Urinary crystallization and stone retention

Calcium oxalate crystallization is influenced not only by conventional urinary ion concentrations but also by urinary organic acids, inorganic ions, and macromolecules. A machine-learning multi-omics study identified urinary metabolomic and ionic profiles associated with calcium oxalate stone formation, supporting metabolic dysregulation as a contributor to urinary risk. ^[238] Proteomic fractionation of urine from calcium oxalate stone formers found multiple fractions that promoted one or more stages of stone pathogenesis, including crystallization, crystal growth, aggregation, and adhesion to renal tubular cells. ^[37]C4 These findings indicate that urinary proteins can act as endogenous promoters rather than being uniformly inhibitory to crystal formation. ^[37]C4

The association between nephrocalcinosis and nephrolithiasis has also been examined morphologically. In a feline postmortem study, high-resolution microradiography was used to identify nephroliths and characterize striated or punctate parenchymal mineralization, providing evidence that intrarenal mineral deposition and discrete stones can coexist within the same kidneys. ^[239] Human translational relevance remains uncertain because this evidence derives from cats. ^[239]

Tubular epithelial injury and crystal-induced inflammation

Calcium oxalate crystals can injure renal tubular epithelial cells through oxidative stress, endoplasmic-reticulum stress, and apoptosis. Experimental work examining serine metabolism linked the SDSL-IDH2 axis with attenuation of reactive oxygen species, endoplasmic-reticulum stress, and tubular epithelial apoptosis, suggesting that amino-acid metabolism may modify crystal-induced cellular injury. ^[242] In mouse and cellular models, calcium oxalate nephropathy has additionally been associated with oxidative stress, inflammation, apoptosis, necroptosis, and fibrosis. ^[38]D5 Nesfatin-1 reduced these pathological responses in a glyoxylate-induced model through GPR12 receptor modulation and inhibition of the PKCα/NADPH oxidase pathway, but these findings remain preclinical. ^[38]D5

Environmental exposures may amplify crystal-related injury. In NHANES-based cross-sectional analysis, urinary glyphosate was associated with nephrolithiasis in a dose-dependent manner; each one-unit increase in log-transformed urinary glyphosate corresponded to a 25% increase in odds of nephrolithiasis (OR 1.25, 95% CI 1.06–1.47). ^[240] Network toxicology and experimental validation implicated PI3K/AKT signaling as a possible mechanism by which glyphosate promotes calcium oxalate crystal-induced renal injury. ^[240] The observational design does not establish causality. ^[240]

Genetic and inherited mechanisms

Primary hyperoxaluria type 1 is caused by biallelic pathogenic variants in AGXT, impairing hepatic glyoxylate metabolism and increasing endogenous oxalate production. Excess oxalate promotes nephrolithiasis and nephrocalcinosis and may progress to kidney failure. ^{[234]C [246]D} A Tunisian clinical-genetic study highlighted the potential importance of consanguinity and regional pathogenic-allele burden in the observed prevalence and pediatric spectrum of PH1. ^[234]C Computational analysis identified the G161C and Y260C AGXT variants as highly deleterious because of predicted effects on protein stability, although computational findings do not substitute for clinical functional validation. ^[246]D

Dent disease is an X-linked proximal tubular disorder caused by pathogenic variants in CLCN5 or OCRL1. In Dent disease type 1, loss of the ClC-5 chloride/proton exchanger disrupts receptor-mediated endocytosis, producing low-molecular-weight proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis, and progressive kidney failure. ^[241]C A multicenter Korean cohort demonstrated variable presentation and frequent delayed recognition, with a median diagnostic age of 6.8 years among genetically confirmed patients. ^[235]C The CLCN5 variant database was developed to improve variant interpretation and diagnostic accuracy in Dent disease type 1. ^[241]C

Normocalcemic primary hyperparathyroidism is characterized by persistently normal serum calcium with elevated parathyroid hormone after exclusion of secondary causes. It is increasingly identified during evaluation for osteoporosis or nephrolithiasis and may be associated with renal complications, although apparent disease burden may be influenced by referral and selection bias. ^[36]D5 Genome-wide and phenome-wide analyses in Taiwanese Han Chinese participants further support a polygenic contribution to kidney stone disease, with polygenic risk scores providing a framework for individual susceptibility assessment. ^[244]D

Systemic, urinary-tract, and obstructive contributors

Inflammatory bowel disease is associated with nephrolithiasis and other kidney complications through gut–kidney interactions, including altered intestinal handling of metabolites and minerals, systemic inflammation, and treatment- or volume-related factors; Crohn disease generally carries greater kidney risk than ulcerative colitis. ^[245]D Symptomatic benign prostatic hyperplasia may increase stone risk because lower-urinary-tract symptoms can lead men to restrict fluid intake, thereby reducing urinary volume; this association was evaluated in a nationwide electronic-health-record cohort of men aged 45–85 years. ^[233]

Urinary diversion can alter urinary chemistry, infection risk, and drainage. After radical cystectomy, ureterostomy was associated with greater late urinary-tract infection and nephrolithiasis propensity in a retrospective institutional study, although confounding by older age and comorbidity is important. ^[237] Renal transplant recipients have distinct metabolic and urological profiles; analysis of 33,616 stone samples, including 69 transplant recipients, examined differences in stone composition between transplant and non-transplant populations. ^[236]

Upper urinary tract obstruction can cause acute renal dysfunction and alter renal hemodynamics. A prospective observational study measured circulating endocannabinoids before and after relief of obstruction, including comparisons between patients with and without acute kidney injury, to characterize endocannabinoid responses during obstructive injury. ^[232]C During ureteroscopy, pyelovenous backflow is conventionally considered possible when intrarenal pressure exceeds 30 mmHg; continuous-pressure monitoring is being evaluated for its relationship to postoperative sepsis. ^[243]D These observations connect obstruction, pressure-mediated renal injury, and infection risk, but do not establish that pressure monitoring predicts sepsis. ^[243]D

Mechanistic synthesis

Overall, stone formation reflects a continuum from inherited or acquired metabolic excess and urinary promoters to crystal retention, epithelial adhesion, oxidative injury, inflammation, fibrosis, obstruction, infection, and recurrent stone events. ^{[14]A1a [37]C4 [38]D5 [240]} The relative contribution of each pathway varies by stone composition, genetic background, comorbidity, urinary anatomy, and exposure history. ^{[234]C [235]C [236] [244]D}

Epidemiology

Nephrolithiasis is a recurrent disorder with clinically important morbidity across age groups. In children, recurrence and morbidity may be substantial, and pediatric stone disease has been associated with risk of chronic kidney damage and, in severe cases, end-stage renal failure. ^[60]A1b The global incidence of urolithiasis has increased over recent decades, and contemporary evidence supports an association between environmental heat exposure and stone-related events. ^[65]A1a

Pediatric nephrolithiasis is influenced by age, stone size and location, metabolic abnormalities, dietary exposures, medications, and inherited disorders. ^[60]A1b Ceftriaxone-associated urinary stones are a specific pediatric drug-related cause; a 2026 systematic review and meta-analysis was undertaken to estimate their pooled frequency separately from ceftriaxone-associated biliary pseudolithiasis and urinary tract calcifications. ^[64]A1a Children receiving ketogenic or modified Atkins diets for drug-resistant epilepsy represent another clinically relevant high-risk population; a tertiary-center cohort of 112 children initiating dietary therapy evaluated stone incidence, associated factors, laboratory findings, and outcomes. ^[255]C

Etiology

Most stones arise from urinary supersaturation with calcium oxalate, calcium phosphate, uric acid, struvite, or cystine, followed by crystal nucleation, growth, aggregation, and retention. The supplied contemporary studies particularly support calcium-based crystallization, hyperuricemia-related mechanisms, infection- or medication-associated stones, and monogenic disorders as important etiologic pathways. ^{[65]A1a[64]A1a[253][234]C}

Inherited disease should be considered in children, patients with recurrent or bilateral stones, nephrocalcinosis, early-onset disease, or a strong family history. Primary hyperoxaluria type 1 is an autosomal-recessive disorder caused by pathogenic variants in AGXT and can produce severe pediatric stone disease and nephrocalcinosis; its burden may be amplified in populations with high consanguinity. ^[234]C Distal renal tubular acidosis is characterized by metabolic acidosis, growth failure, nephrocalcinosis, nephrolithiasis, and chronic kidney disease; prospective registry data collected plasma and urine biochemistry, genetics, treatment, and clinical manifestations to evaluate disease outcomes. ^[249]

Disordered calcium–parathyroid physiology is another established pathway. Primary hyperparathyroidism can cause renal involvement, including nephrolithiasis, while also producing skeletal complications; a Romanian cohort of 413 patients demonstrated the heterogeneous clinical phenotype of primary hyperparathyroidism, including renal and bone manifestations. ^[254] Conversely, permanent hypoparathyroidism is commonly treated with calcium and active vitamin D, therapies that may contribute to hypercalciuria and renal calcification; in a cohort of 958 adults, hypercalciuria was reported in 44.4%, and nephrolithiasis or nephrocalcinosis in 13.5%. ^[251]

Established and emerging risk factors

Low urine volume and dehydration increase urinary supersaturation and are central preventable risks. Higher ambient temperatures are associated in most reviewed studies with increased kidney-stone events, including acute renal colic; proposed mechanisms include increased urinary calcium excretion and greater calcium oxalate and calcium phosphate supersaturation. ^[65]A1a Symptomatic benign prostatic hyperplasia may indirectly increase risk because men may restrict fluid intake to control lower urinary tract symptoms; a nationwide retrospective cohort evaluated incident stones in men aged 45–85 years with and without symptomatic BPH. ^[233]

Dietary and lifestyle patterns also modify risk. A wearable-device cohort of U.S. adults without previous stone disease examined longitudinal Fitbit-derived daily steps, active minutes, and sedentary time in relation to incident stones, extending earlier observational evidence that physical activity may be protective. ^[250] In the UK Biobank, a higher Oxidative Balance Score—calculated from 13 dietary and 5 lifestyle components—was evaluated against incident nephrolithiasis, with genetic susceptibility assessed using a polygenic risk score based on 20 single-nucleotide polymorphisms. ^[67]B2b These studies support consideration of the combined dietary, activity, sedentary, and inherited-risk profile rather than any single lifestyle variable. ^[67]B2b[250]

Family history is an important marker of susceptibility. In a specialized stone-clinic cohort of 101 patients, family history was assessed against hypercalciuria, hyperoxaluria, hyperuricosuria, hypocitraturia, cystinuria, hypomagnesuria, and stone composition, with analyses adjusted for age, sex, body mass index, diabetes, hypertension, and metabolic syndrome. ^[127]B3b Genetic predisposition is also implicated in urate handling and stone formation: a Taiwanese case-control study of 35,280 adults examined ABCG2 rs4148155 and SLC22A12 rs75786299, serum uric acid, gout, and ultrasound-confirmed nephrolithiasis. ^[253] Gout phenotypes characterized by serum urate, fractional uric-acid excretion, gout duration, and stone burden may have different subsequent chronic kidney disease trajectories. ^[248]

Potentially modifiable metabolic and environmental exposures include obesity-related metabolic disease, diabetes, hypertension, metabolic syndrome, hyperuricemia, hypercalciuria, hyperoxaluria, hypocitraturia, and medication exposure. ^{[127]B3b[248][253]} A cross-sectional NHANES analysis reported a dose-dependent association between urinary glyphosate concentration and nephrolithiasis; each unit increase in log-transformed glyphosate was associated with 25% higher odds of nephrolithiasis (OR 1.25, 95% CI 1.06–1.47). ^[240] This association is observational and does not establish causality. ^[240]

Anatomic and urinary-tract factors can promote urinary stasis or recurrent infection. Congenital pelvic kidneys are associated with altered anatomy and technically complex stone management, and a multicenter study evaluated nephrolithiasis in this population. ^[252] After radical cystectomy, urinary diversion type and related complications may influence late urinary tract infection and nephrolithiasis risk; a 10-year institutional study of 574 patients identified greater late complication burden among patients undergoing ureterostomy, although differences may reflect age and comorbidity. ^[237] Hospitalized urology patients may develop acute kidney injury, making obstruction, infection, and renal functional consequences clinically important in severe or complicated stone disease. ^[68]B3b

Clinical implications

Risk assessment should integrate age at onset, recurrence, family history, stone composition, urine volume, dietary and activity patterns, serum calcium and urate, urinary calcium/oxalate/uric acid/citrate, medication exposures, infection, anatomic abnormalities, and clinical features suggesting dRTA, primary hyperoxaluria, hyperparathyroidism, or hypoparathyroidism. ^{[60]A1b[64]A1a[127]B3b[234]C[249][251][254]} Pediatric patients, recurrent stone formers, patients with nephrocalcinosis, and those with systemic or inherited disease warrant particular attention because recurrence and renal morbidity may be substantial. ^{[60]A1b[234]C[249]}

Overview

Nephrolithiasis has a broad clinical spectrum, ranging from incidental radiologic detection to acute renal colic, hematuria, recurrent urinary symptoms, nephrocalcinosis, and progressive kidney disease. Clinical expression is influenced by age, stone burden, obstruction, infection, metabolic abnormalities, and the underlying genetic or systemic disorder. Pediatric and adult presentations may differ substantially, and the absence of symptoms does not exclude a substantial stone burden.^{[258][259]C[262][263]C}

Adults

Adults may present with acute flank pain or renal colic, macroscopic or microscopic hematuria, urinary symptoms, or incidental stones identified during imaging for another indication. Hematuria and flank pain are also among the symptoms used in primary-care assessment when deciding whether urine culture is clinically appropriate, although nephrolithiasis itself was not the primary outcome of that study.^[260] Some stones remain clinically silent: children with enamel renal syndrome had multiple bilateral stones, and one family had nephrocalcinosis, despite no microscopic or macroscopic hematuria and no renal colic.^[97]C4

Primary hyperparathyroidism (PHPT) can present with nephrolithiasis as part of a broader mineral-metabolism phenotype. Contemporary Western cohorts are described as predominantly asymptomatic, whereas symptomatic renal and skeletal manifestations remain common in some settings.^[254] In a Romanian tertiary-center cohort of 413 patients diagnosed between 2000 and 2020, PHPT was characterized across clinical, biochemical, skeletal, and renal domains, reflecting a heterogeneous presentation rather than a uniform asymptomatic disorder.^[254] Calcium-containing stones are an infrequent but recognized manifestation of PHPT despite hypercalciuria.^[92]A1a Nephrolithiasis may also occur during pregnancy complicated by PHPT; reported maternal complications include nephrolithiasis, pancreatitis, and preeclampsia, with potential adverse fetal outcomes.^[96]C4

The age at symptom onset may provide a clinical clue to systemic metabolic disease. In an observational cohort of 546 patients with confirmed nephrolithiasis, patients were categorized as early onset at <45 years and late onset at ≥45 years, with sociodemographic, lifestyle, urinalysis, and biochemical factors compared between groups.^[261] The study specifically evaluated whether age of onset was associated with clinical and metabolic characteristics, supporting consideration of an underlying systemic disorder when stones occur unusually early.^[261]

Symptomatic benign prostatic hyperplasia (BPH) may represent an additional context in which stones develop in older men. A nationwide retrospective cohort study evaluated men aged 45–85 years with and without symptomatic BPH, based on the hypothesis that lower fluid intake used to control lower urinary tract symptoms could increase stone risk.^[233] The available evidence establishes the clinical rationale and study design but does not provide the comparative incidence estimates in the supplied abstract.^[233]

Children and adolescents

Pediatric nephrolithiasis commonly presents with hematuria, flank or abdominal pain, dysuria, urinary tract infection, or incidental imaging findings; however, the clinical phenotype varies with age and cause. In a pediatric observational study including patients aged 1 month to 18 years with nephrolithiasis or nephrocalcinosis, hematuria was investigated as a diagnostic marker in the absence of acute obstruction or infection.^[258] The study excluded systemic disease, urinary tract infection, genitourinary anomalies, familial hematuria, recent trauma, fever, tumors, and recent kidney colic, thereby focusing on hematuria associated with nonacute pediatric stone disease.^[258]

Nephrocalcinosis is particularly important in infants and young children because it may be the presenting manifestation of congenital, tubular, metabolic, or genetic disease. In a tertiary pediatric-hospital series of 50 children, 50% were younger than 2 years, and congenital disorders were identified in 54%; renal tubular acidosis accounted for 44% of the reported etiologies.^[263]C Pediatric nephrolithiasis and nephrocalcinosis may therefore warrant evaluation for an inherited or metabolic cause, particularly with very early onset, bilateral disease, nephrocalcinosis, recurrent stones, growth or electrolyte abnormalities, or a suggestive family history.^{[259]C[262][263]C}

Genetic disease can present with recurrent stones, nephrocalcinosis, chronic kidney disease, or a combination of these findings. In a Saudi Arabian pediatric cohort, 186 children had radiologically confirmed nephrolithiasis or nephrocalcinosis, and 54 (29.03%) underwent genetic testing; the study assessed the spectrum of pathogenic variants and associated clinical, biochemical, and radiologic features.^[259]C Primary hyperoxaluria is an autosomal-recessive disorder causing excessive hepatic oxalate production and may present with recurrent stones, nephrocalcinosis, progressive chronic kidney disease, or kidney failure.^[256][265] Diagnosis may be substantially delayed, particularly in adults: in a French cohort diagnosed between 2015 and 2019, the reported median diagnostic delay was 1.2 years in children versus 30 years in adults.^[256] Increased recognition after approval of the first RNA-interfering therapy in 2020 was investigated as a possible factor in reducing diagnostic delay.^[256]

A prospective study from northwestern India evaluated children <18 years with radiologically confirmed nephrolithiasis using clinical assessment and first-line metabolic testing, with stone analysis and whole-exome sequencing performed when indicated.^[262] The study illustrates the multifactorial pediatric presentation, in which environmental exposure, metabolic abnormalities, stone composition, and monogenic disease may coexist.^[262]

Syndromic and atypical presentations

Enamel renal syndrome caused by biallelic FAM20A loss-of-function variants combines dental abnormalities with renal stones, nephrocalcinosis, hypophosphatemia, and distinctive calcium-handling abnormalities.^[97]C4 In four pediatric cases, all patients had multiple bilateral nephrolithiasis and one family had nephrocalcinosis, but none reported hematuria or renal colic; all were referred for renal assessment by a specialized dental team at a median age of 14.5 years.^[97]C4

Medullary sponge kidney may be asymptomatic or may present with hematuria, nephrolithiasis, or urinary tract infection.^[267]C A reported 11-year-old boy with a TRIM8 variant had incidental proteinuria and increased medullary echogenicity on ultrasonography suggestive of medullary sponge kidney, illustrating that a renal imaging abnormality may be detected before classic stone symptoms.^[267]C

Rare endocrine and paraneoplastic disorders can complicate the interpretation of nephrolithiasis. Tumor-induced osteomalacia masked by parathyroid carcinoma was reported in a 74-year-old woman with fragility fractures, generalized bone pain, and nephrolithiasis; hypercalcemia, hypophosphatemia, and elevated PTH initially suggested PHPT, but symptoms persisted after parathyroidectomy.^[94]C4 Autosomal dominant hypocalcemia type 1 is another inherited calcium-sensing disorder in which renal involvement and ectopic calcifications are clinically relevant; a genetically confirmed adult case series specifically assessed renal, skeletal, and cerebral manifestations.^[95]C4

Clinical assessment implications

Stone symptoms should be interpreted together with age of onset, laterality and burden, hematuria, nephrocalcinosis, renal function, electrolyte abnormalities, skeletal findings, dental abnormalities, and family history.^{[97]C4[254][259]C[262][263]C} Recurrent or bilateral disease, infantile presentation, nephrocalcinosis, chronic kidney disease, or unusual biochemical findings should raise suspicion for primary hyperoxaluria, PHPT, renal tubular acidosis, enamel renal syndrome, medullary sponge kidney, or another monogenic disorder.^{[92]A1a[97]C4[256][259]C[262][263]C[267]C}

Initial clinical assessment

Evaluate suspected nephrolithiasis using the presenting symptoms, examination findings, urinalysis, renal function, and imaging, while specifically documenting age, pregnancy status, solitary-kidney status, fever or suspected infection, prior stones, family history, relevant comorbidities, medications, and dietary or environmental exposures. The supplied evidence identifies recurrent disease, pediatric age, cystic fibrosis, ceftriaxone exposure, hereditary tubulopathies, primary hyperoxaluria, renal transplantation, and higher ambient temperature as clinically relevant contexts for urinary abnormalities or stone risk. ^{[64]A1a[65]A1a[127]B3b[234]C[235]C[236][257][268]}

Family history should be recorded because patients with a family history of kidney stones were specifically evaluated for associations with hypercalciuria, hyperoxaluria, hyperuricosuria, hypocitraturia, cystinuria, hypomagnesuria, and stone composition. ^[127]B3b In a child, obtain a detailed pedigree and consider an inherited or monogenic disorder when stones are early-onset, recurrent, severe, associated with nephrocalcinosis, or accompanied by tubular abnormalities; the cited pediatric cohorts describe genetically confirmed primary hyperoxaluria type 1 caused by pathogenic AGXT variants and Dent disease caused by CLCN5 or OCRL1 variants. ^[234]C[235]C

Medication and exposure history is essential in children receiving ceftriaxone because a systematic review specifically assessed ceftriaxone-induced urolithiasis rather than biliary pseudolithiasis. ^[64]A1a Ask about ketogenic diet therapy and cystic fibrosis, because urinary abnormalities in children receiving ketogenic diet therapy and calcium oxalate crystalluria or renal calculi in children with cystic fibrosis have been reported in the supplied evidence. ^[257][268] Document heat exposure and hydration patterns because most studies in a systematic review reported a positive association between higher ambient temperature and kidney-stone-related events, with proposed mechanisms including increased urinary calcium excretion and increased calcium oxalate or calcium phosphate supersaturation. ^[65]A1a

Laboratory evaluation

Urinalysis should assess hematuria, pyuria, urinary pH, crystals, and evidence of infection, with urine culture when infection is suspected; serum creatinine and other renal-function measures are important when obstruction, infection, bilateral disease, or a solitary kidney is possible. The supplied studies directly support attention to routine urinalysis, urine biochemical measurements, crystalluria, renal function, and infection status in selected populations, although they do not provide a validated universal laboratory algorithm. ^{[64]A1a[65]A1a[127]B3b[268][271]}

Stone analysis should be pursued whenever a stone or fragment is available. Composition data are particularly relevant in recurrent disease, pediatric disease, suspected drug-associated stones, hereditary disorders, and transplant recipients; a large observational analysis used Fourier-transform infrared spectrometry to characterize 33,616 urinary stone samples and compared 69 renal-transplant recipients with non-transplant stone-forming controls. ^{[64]A1a[127]B3b[234]C[235]C[236]}

For recurrent, pediatric, bilateral, unusual, or high-risk disease, consider metabolic evaluation with urine calcium, oxalate, uric acid, citrate, cystine, magnesium, and related measurements because these abnormalities were specifically examined in relation to family history and hereditary disease. ^{[127]B3b[234]C[235]C} Genetic testing or specialist nephrology assessment is appropriate when the phenotype suggests primary hyperoxaluria or Dent disease; the cited studies confirm that molecular diagnosis can establish these conditions but do not define a single testing panel or sequencing strategy for all stone formers. ^[234]C[235]C

Imaging strategy

Ultrasound is commonly used as a first-line modality, but its sensitivity is limited and performance is operator dependent; a systematic review evaluated artificial-intelligence and deep-learning applications for ultrasound-based stone detection, classification, complication prediction, and procedural guidance, while emphasizing heterogeneous evidence. ^[2]D5 AI-assisted ultrasound should therefore be regarded as an emerging adjunct rather than a replacement for clinical assessment or established imaging, because the review did not establish uniform diagnostic accuracy or clinical implementation standards. ^[2]D5

When ultrasound is nondiagnostic, complications are suspected, or precise anatomic characterization is required, cross-sectional imaging may be needed. CT-based measurements are particularly relevant for defining stone size and volume: studies of renal stones 2–3 cm, stones >2 cm in a solitary kidney, and steerable ureteroscopic evacuation used preoperative CT to characterize stone burden. ^{[101]A1a[270][273]} Imaging should report the number, laterality, maximal diameter, location, obstruction or hydronephrosis, renal anatomy, and—when available—stone volume, because these parameters were used to compare treatment strategies and define stone-free outcomes. ^{[101]A1a[111]A1a[252][270][273]}

Assess renal anatomy carefully in ectopic or transplanted kidneys. A multicenter study of pelvic kidneys evaluated flexible ureteroscopy, multimodal-guided percutaneous nephrolithotomy, and laparoscopic pyelolithotomy, demonstrating that congenital anatomy materially affects procedural planning. ^[252] In renal-transplant recipients, stone composition and the feasibility of ex vivo back-table stone removal have been specifically studied, so transplant status should be identified before selecting imaging and intervention pathways. ^[236][269]

Infection and unusual diagnostic scenarios

Infection assessment is a priority when fever, pyuria, systemic illness, obstruction, or an infected stone is suspected. An exploratory multicenter study evaluated 18F-FDG PET/CT for kidney-stone-related renal infection in 120 lung-cancer patients with radiologically confirmed nephrolithiasis and correlated PET findings with stone burden and inflammatory biomarkers; this remains specialized evidence rather than routine diagnostic practice. ^[271]

Interpretation and documentation

Record whether a stone is symptomatic or asymptomatic, because randomized-trial evidence has specifically compared intervention with observation for asymptomatic kidney stones and recognizes subsequent pain, obstruction, infection, stone growth, and intervention as clinically relevant outcomes. ^[14]A1a For treatment-oriented planning, document stone size thresholds accurately: contemporary comparative studies address renal stones 1–2 cm in young children, <20 mm in pediatric patients, 2–3 cm renal stones, and stones >2 cm in solitary kidneys. ^{[60]A1b[101]A1a[270]} Stone-free status is not uniformly defined across studies, with one pelvic-kidney study requiring 0 mm and another allowing residual fragments <5 mm on ultrasound or radiography; the definition used should therefore be stated explicitly in follow-up documentation. ^{[111]A1a[252][273]}

Clinical severity: uncomplicated versus complicated obstruction

Severity assessment begins by determining whether a stone is causing clinically significant urinary obstruction and whether obstruction is accompanied by acute kidney injury, acute renal failure, infection, or sepsis. Acute obstructive uropathy with renal failure or sepsis is a medical emergency and requires prompt attention to prevent further clinical deterioration. ^[121]A1c Management options for an acute obstructive process include conservative medical treatment, retrograde ureteral stenting, and percutaneous nephrostomy or nephroureteral catheter placement; the appropriate option depends on the clinical scenario and should prompt urologic and, when indicated, interventional radiology consultation. ^[121]A1c

AKI is an important severity marker in hospitalized urology patients. A 2026 retrospective cohort evaluated AKI using KDIGO serum-creatinine criteria and developed an exploratory admission-based risk-stratification model from demographic, clinical, laboratory, and procedural variables; because the study was retrospective and limited to a tertiary urology ward, its model should be considered exploratory rather than a validated nephrolithiasis staging system. ^[68]B3b

Imaging and anatomic staging

Imaging-based characterization should document stone number, laterality, location, size, obstruction, and renal or ureteral consequences. In children and adolescents presenting with hematuria, evaluation begins with history and urine assessment, and the need for imaging depends on the clinical scenario and suspected cause; ultrasound and CT are the most commonly used imaging methods, with other modalities selected selectively. ^[122]A1c

Stone burden and location influence procedural complexity and treatment selection. A systematic review specifically evaluated flexible ureteroscopy and lasertripsy for lower-pole renal stones <2 cm, comparing treatment in situ with displacement to the upper pole; this evidence supports recognizing lower-pole location and the 2-cm size boundary as clinically relevant stratification variables, although the supplied abstract does not report the pooled comparative outcomes. ^[99]A1a Super-mini percutaneous nephrolithotomy has also been evaluated for moderate-size and larger urinary calculi in a systematic review and meta-analysis of 9 studies including 2,433 SMP patients and 2,178 controls, with stone-free rate as the primary outcome and Clavien–Dindo complications, pain, hospitalization, and hemoglobin decline as secondary outcomes. ^[276]

For suspected uric-acid stones, CT density may help distinguish pure from mixed composition. In a retrospective cohort of patients with predominantly uric-acid stones, 62.2% had pure uric-acid stones (defined as ≥95% uric acid), whereas 37.8% had mixed stones containing 50–90% uric acid; mean stone density was lower for pure than mixed stones (450 vs 600 HU), and the proportion of radiopaque stones was also lower in the pure-stone group. ^[125]B3b

Infection and perioperative risk

Infection-associated obstruction and infectious risk around stone surgery require separate risk assessment from stone size alone. In patients undergoing PCNL who had either a positive preoperative urine culture or an indwelling urinary drainage tube, a randomized EDGE Consortium trial compared 2 versus 7 days of preoperative antibiotics; the study addressed postoperative sepsis risk in a moderate- to high-risk population, whereas prior work cited by the investigators found no sepsis reduction from 7 days compared with perioperative antibiotics in a low-risk PCNL population. ^[117]A1b

Post-PCNL infection risk may also relate to stone microbiology and host inflammatory factors. In a retrospective series of 293 PCNL patients, positive stone cultures were reported in 56% and multiple-organism cultures in 25%; multivariable analysis was used to examine associations with postoperative complications. ^[277] Another retrospective study of 399 PCNL patients evaluated postoperative systemic inflammatory response syndrome and developed a nomogram incorporating independent clinical and laboratory risk factors, including the peripheral PD-1^hiCXCR5− CD4+ T-cell population termed peripheral T-helper cells. ^[278]

Recurrence risk

Recurrence risk should be stratified separately from the acute severity of the presenting stone. Genetic predisposition is biologically plausible but heterogeneous: a systematic review and causal-network analysis evaluated human case-control and genome-wide association studies published from 2007–2017 to identify potentially causative genes for idiopathic urolithiasis and inform future molecularly targeted prevention. ^[274] In a prospective 5-year study of 1,001 patients rendered stone-free by CT after surgical removal, 49 SNPs were genotyped and combined with clinical variables to construct a recurrence-prediction nomogram. ^[275]

Clinical subgroups may carry distinct recurrence and kidney-outcome risks. In patients with primary hyperparathyroidism, a retrospective cohort of 197 patients used demographic, biochemical, urine, stone, and treatment variables with LASSO selection to develop and validate a recurrence nomogram. ^[281] In unilateral nephrolithiasis, high perirenal fat thickness was associated with higher BMI and hyperlipidemia and was evaluated as a predictor of recurrence-free survival in a retrospective cohort of 81 patients. ^[280] Among patients with type 2 diabetes and pre-existing nephrolithiasis, including those with concomitant gout, target-trial emulation studies compared SGLT-2 inhibitors with GLP-1 receptor agonists and DPP-4 inhibitors for recurrent nephrolithiasis outcomes. ^[279]

Family history may identify patients needing metabolic evaluation, although the available evidence is limited: a 2026 retrospective stone-clinic study of 101 patients examined associations between family history, hypercalciuria, hyperoxaluria, hyperuricosuria, hypocitraturia, cystinuria, hypomagnesuria, and stone composition. ^[127]B3b In gout, a prospective Chinese cohort of 1,497 patients used clustering based on serum urate, fractional urate excretion, gout duration, and kidney-stone burden to evaluate progression to CKD stage ≥3 and assessed whether a 20-SNP genetic risk score improved prediction. ^[248]

ADPKD represents a special high-risk context. A prospective cohort of 410 patients used baseline CT-confirmed collecting-system stones, excluding cyst-wall calcifications, and assessed initiation of renal replacement therapy as a long-term kidney outcome. ^[191]B2b Finally, among patients initially selected for surveillance after acute ureteric colic, a retrospective cohort of 870 eligible patients developed and independently validated a nomogram for subsequent surgical intervention using clinical and stone-related variables. ^[126]B3b

Practical risk tiers

• Emergent/high severity: obstruction with sepsis, acute renal failure, or clinically important AKI; urgent decompression and definitive planning are required. ^{[121]A1c[68]B3b}
• Higher procedural risk: infected or instrumented systems, positive urine or stone cultures, multiple-organism cultures, inflammatory-risk markers, large or anatomically difficult stones, and lower-pole stones. ^{[117]A1b[277][278][99]A1a[276]}
• Higher recurrence or kidney-progression risk: genetic susceptibility, family history, primary hyperparathyroidism, gout with stone burden, obesity-related perirenal fat, diabetes, ADPKD, or prior stone disease. ^{[274][275][127]B3b[281][248][280][279][191]B2b}
• Surveillance failure risk: clinical and stone characteristics can predict later need for surgery after an initial decision for observation; validated nomogram use may support follow-up intensity and earlier intervention planning. ^[126]B3b

Immediate priorities

Acute nephrolithiasis management begins with rapid assessment of pain, urinary obstruction, infection, kidney function, and alternative causes of an acute abdomen or flank pain. The 2026 AUA surgical-management guideline series provides the principal framework for evaluation, treatment selection, and future directions in kidney and ureteral stones ^{[9]A1c[10]A1c[11]A1c}. Initial evaluation should establish symptom severity, vital-sign abnormalities, urinalysis and urine culture when infection is possible, serum creatinine, and imaging sufficient to define stone location, burden, and obstruction ^[10]A1c. Patients with systemic infection, an obstructed collecting system, or deteriorating renal function require urgent urologic assessment rather than routine outpatient stone passage management ^{[10]A1c[11]A1c}.

Analgesia and emergency supportive care

Pain control should be prompt and reassessed serially. An electronic health-record clinical pathway for emergency-department nephrolithiasis was developed to reduce variation in acute care, unnecessary opioid exposure, and inadequate discharge planning; the pathway targeted analgesic use, discharge processes, and repeat visits ^[288]. This supports a structured approach combining nonopioid analgesia when clinically appropriate, rescue opioid therapy when necessary, antiemetics, hydration directed by volume status, and explicit return precautions ^[288]. Opioid-free discharge after PCNL was prospectively studied using preoperative counseling, multimodal analgesia, and detailed postoperative instructions, demonstrating the feasibility of reducing routine opioid prescribing after stone surgery ^[287]C. These postoperative findings should not be extrapolated to uncontrolled emergency renal colic, but they support multimodal, opioid-sparing care when pain is adequately controlled ^[287]C.

Higher ambient temperatures are associated with increased kidney-stone-related events, including acute renal colic, in a systematic review and meta-analysis; proposed mechanisms include increased urinary calcium excretion and urinary supersaturation ^[65]A1a. During heat exposure, clinicians should therefore address dehydration risk and provide individualized hydration advice, while avoiding indiscriminate high-volume intravenous fluids in patients with obstruction, heart failure, or other fluid-sensitive conditions ^[65]A1a.

When decompression is urgent

An infected, obstructed urinary system is a urologic emergency. When obstruction is accompanied by suspected or confirmed infection, sepsis, hemodynamic instability, or clinically important renal dysfunction, management should prioritize cultures, immediate antimicrobial therapy, resuscitation when indicated, and urgent drainage with either ureteral stenting or percutaneous nephrostomy; definitive stone treatment should generally be deferred until the acute infectious process has been controlled ^{[10]A1c[11]A1c}. The AUA guideline series specifically addresses evaluation, treatment, surgical management, and future directions for kidney and ureteral stones ^{[9]A1c[10]A1c[11]A1c}.

Relief of upper-urinary-tract obstruction is clinically relevant to acute kidney injury. A prospective observational study measured circulating endocannabinoid responses before and after relief of upper-tract obstruction and specifically compared patients with and without AKI, supporting investigation of biologic responses associated with obstruction relief ^[232]C. This study does not establish a decompression threshold or a treatment effect, but it reinforces that obstruction with AKI warrants prompt evaluation and should not be managed solely by observation ^[232]C.

Selecting patients for early intervention

Not every patient with renal colic requires immediate surgery. The decision to observe, pursue medical expulsive management, or intervene should incorporate stone size and location, obstruction, infection, renal function, symptom control, patient preference, and likelihood of spontaneous passage ^{[10]A1c[11]A1c}. In a prospective five-emergency-department cohort, 602 adults presenting with renal colic were studied and 60 patients (10%) underwent surgery within 7 days; the CLAD-MB score was prospectively refined to predict this outcome ^[137]B2b. Such prediction tools may help identify patients likely to need early intervention, but they complement rather than replace clinical assessment, imaging, and urologic judgment ^[137]B2b.

Procedural considerations after stabilization

The AUA guideline series covers surgical options for kidney and ureteral stones, including selection of definitive treatment after emergency stabilization ^{[9]A1c[10]A1c[11]A1c}. For retrograde intrarenal surgery, a randomized trial of 126 patients compared pre-stented and non-stented procedures while assessing operative time, access-sheath insertion, stone-free outcomes, and postoperative complications ^[140]A1b. Pre-stenting should therefore be considered an operative-planning decision rather than an automatic requirement for every patient ^[140]A1b.

In patients at high risk for infectious complications, infection prevention is central. A multicenter trial evaluated flexible, navigable suction ureteral access sheath-assisted retrograde intrarenal surgery under local anesthesia in patients with stones up to 30 mm and persistent asymptomatic bacteriuria or pyuria despite antibiotic therapy, with postoperative fever and sepsis as key safety concerns ^[282]. These findings are investigational and do not justify proceeding with definitive endoscopic treatment in an uncontrolled infected obstruction ^[282]. Stone cultures are also clinically relevant: in a retrospective PCNL cohort, 56% of patients had positive stone cultures and 25% had cultures containing multiple organisms ^[277]. Culture-directed perioperative planning should be integrated with urine culture, clinical status, and institutional protocols ^[277].

Discharge and follow-up

A patient considered for outpatient management should have controlled symptoms, stable renal function, no evidence of infected obstruction, an appropriate follow-up plan, and clear instructions to return for fever, rigors, worsening or refractory pain, vomiting, reduced urine output, syncope, or clinical deterioration ^{[10]A1c[11]A1c[288]}. Follow-up systems require attention to access barriers: in an urban cohort after emergency-department renal-colic visits, preferred language was evaluated in relation to time to clinic review, time to surgery, repeat emergency visits, metabolic testing, and failure to undergo surgery ^[284]. Discharge communication should therefore use professional interpretation when needed and document the timing and pathway for urologic follow-up ^[284].

Management principles

Long-term care has two complementary objectives: definitive clearance of clinically important stone burden and reduction of recurrence risk. The 2026 AUA medical-management guideline is intended to provide a framework for treatment and follow-up of patients with prior kidney stones, specifically to reduce recurrent disease; this section should therefore be applied alongside individualized metabolic evaluation, prevention planning, and surveillance rather than as a substitute for them. ^[290] Available metabolic evidence continues to support stratifying prevention strategies according to stone composition and urinary risk factors; a 2026 study specifically examined urine volume, calcium, citrate, oxalate, uric acid, sodium, magnesium, serum calcium, vitamin D, parathyroid hormone, and urine pH in pure versus mixed calcium-oxalate stone formers. ^[294]

Observation versus definitive intervention

Observation is a reasonable management pathway for many asymptomatic renal stones because a substantial proportion remain stable; however, later pain, obstruction, infection, stone growth, or intervention may occur. A 2026 systematic review and meta-analysis of randomized trials compared active stone-directed treatment with observation and describes current guideline-based care as generally favoring surveillance for many asymptomatic stones, with shared decision-making based on patient and stone characteristics. ^[14]A1a Intervention becomes more compelling when the stone causes symptoms, obstruction, infection, clinically important growth, recurrent events, impaired drainage, or a high-risk occupational or patient context; the decision should balance expected stone clearance against procedural morbidity, cost, quality of life, and the possibility of staged treatment. ^{[14]A1a[111]A1a}

Choice of endourologic procedure

The principal definitive modalities remain extracorporeal shock-wave lithotripsy (SWL), ureteroscopy or retrograde intrarenal surgery (URS/RIRS), and percutaneous nephrolithotomy (PCNL). They differ in stone-free efficacy, invasiveness, cost, and patient-reported quality of life, so stone-free rate alone is an incomplete endpoint. ^[111]A1a PCNL remains the reference approach for larger or complex renal calculi. ^[291][293]C

For 2–3 cm renal stones, a 2026 meta-analysis of randomized trials directly compared flexible-and-navigable suction-sheath RIRS (FANS-RIRS) with mini-PCNL, evaluating stone-free rate, perioperative outcomes, and hemorrhagic and infectious complications. ^[101]A1a These suction-assisted approaches are promising but should not automatically replace PCNL when a high probability of single-session clearance is required, because the cited evidence establishes comparative evaluation rather than a universal treatment preference. ^[101]A1a

For stones >2 cm in a solitary kidney, a propensity-matched study compared FANS flexible URS with mini-PCNL using a hierarchical endpoint incorporating complications, 1-month stone-free rate, and postoperative length of stay. ^[270] The study design supports individualized selection in solitary-kidney patients but, because it is retrospective, does not establish equivalence or superiority. ^[270] Vacuum-assisted mini-PCNL and FANS-RIRS have also been compared retrospectively in children with 1–3 cm upper-tract stones; among matched children, reported stone-free rates were 97.3% versus 91.3%, respectively. ^[292]

In children younger than 6 years with 1–2 cm renal stones, a prospective randomized study compared mini-PCNL with SWL, reflecting the need to consider age, stone size, location, composition, anesthesia, and recurrence risk when choosing definitive therapy. ^[60]A1b Pediatric flexible ureteroscopy is expanding, including low-profile single-use instruments, but the cited preliminary series included only 11 children undergoing 15 procedures, with median stone size 9 mm and a range of 5–27 mm; this remains limited evidence for broadening indications. ^[272]C

Complex, bilateral, and anatomically challenging disease

Bilateral complex stone disease may be treated with staged or same-session bilateral PCNL. A 2026 meta-analysis evaluated stone-free rate, safety, and efficiency of same-session bilateral PCNL versus staged bilateral PCNL, while another meta-analysis compared synchronous bilateral PCNL with staged unilateral PCNL using stone-free rate and Clavien–Dindo complications as primary outcomes. ^{[112]A1a[202]A1a} These analyses support discussing a same-session strategy in appropriately selected patients, but bilateral treatment should be individualized according to stone burden, infection risk, renal function, operative duration, and available expertise. ^{[112]A1a[202]A1a}

Technical refinements may reduce procedural burden without changing the underlying indication. In conventional fluoroscopy-guided PCNL, a systematic review compared single-shot with gradual tract dilation, specifically excluding mini- and micro-PCNL. ^[291] Tubeless PCNL has been studied for pain reduction; in a randomized trial of patients with solitary renal pelvic stones <3 cm, tract infiltration with 0.25% bupivacaine was evaluated against no infiltration. ^[283] Robotic-assisted mini-PCNL with combined ureteroscopic lithotripsy has early prospective safety and efficacy data, but the reported experience is preliminary and limited to two institutions with follow-up to 90 days. ^[293]C

Anatomic variation may require multimodal planning. In a multicenter series of pelvic kidneys, flexible ureteroscopy was the most common primary treatment (51.1%), followed by multimodal-guided PCNL (33.3%); nearly half of stones were classified as complex GUYS III–IV. ^[252] Ex-vivo back-table ureteroscopy and other stone-removal techniques during renal transplantation are emerging options intended to expand the donor pool, but the evidence is a systematic review of reported cases rather than comparative long-term outcome data. ^[269]

Infection, safety, and follow-up

Infection risk must be addressed before definitive treatment. A multicenter study of FANS-assisted RIRS under local anesthesia enrolled patients with stones ≤30 mm and persistent asymptomatic bacteriuria or pyuria after antibiotic therapy; because it was a single-arm study, it cannot prove superiority over standard treatment. ^[282] In a PCNL cohort, positive stone cultures occurred in 56% of patients and multiple organisms in 25%, underscoring the relevance of stone and urine microbiology to postoperative-risk assessment. ^[277] Allergies to iodinated contrast did not necessarily predict severe reactions during genitourinary surgery in a retrospective study of URS and PCNL, but individualized perioperative assessment remains necessary. ^[295]

After clearance, follow-up should verify residual fragments, monitor recurrence, and implement the AUA medical-management framework. ^[290] New suction-evacuation technologies, including steerable ureteroscopic evacuation systems, are being evaluated to define effective upper size limits; current retrospective work specifically examined whether 3 cm represents a practical boundary, so these technologies should be regarded as evolving rather than established replacements for PCNL. ^[273]

From episodic stone removal to recurrence prevention

Treatment of nephrolithiasis has evolved from addressing an individual obstructing stone to combining stone clearance with long-term metabolic prevention, dietary counseling, pharmacotherapy, and surveillance. Contemporary management is explicitly framed around reducing recurrent disease in patients with a history of kidney stones, with treatment and follow-up addressed in the 2026 American Urological Association guideline update ^[290]. The guideline was developed from an evidence review conducted by the RTI International–University of North Carolina Evidence-based Practice Center under AHRQ contract and PCORI funding ^[290].

The modern treatment pathway begins with characterization of stone burden, location, composition, recurrence risk, comorbidity, renal function, and—particularly in children or recurrent stone formers—metabolic or genetic drivers. Family history is clinically relevant: in a 2022–2025 specialist-clinic cohort of 101 patients, family history was evaluated against hypercalciuria, hyperoxaluria, hyperuricosuria, hypocitraturia, cystinuria, hypomagnesuria, and stone composition, supporting individualized metabolic assessment rather than treatment based solely on imaging ^[127]B3b. A related analysis of 49 calcium oxalate stone formers found that 51% had pure calcium oxalate stones and 49% had mixed calcium oxalate stones, emphasizing that composition may identify distinct metabolic management needs ^[294].

Development of minimally invasive stone clearance

Surgical treatment has progressed from open procedures to endoscopic and percutaneous techniques, with extracorporeal shock-wave lithotripsy (SWL) providing a noninvasive option and mini-percutaneous nephrolithotomy (mini-PCNL) reducing percutaneous tract size. In a prospective randomized pediatric trial involving children younger than 6 years with renal stones smaller than 20 mm, mini-PCNL and SWL were directly compared for stones measuring 1–2 cm ^[60]A1b. The study reflects the contemporary principle that pediatric treatment should be selected according to stone size, location, and composition while accounting for the elevated recurrence and morbidity burden of childhood nephrolithiasis, including risk of end-stage kidney disease ^[60]A1b. Pediatric care therefore combines dietary modification, pharmacological therapy, and intervention rather than relying on stone removal alone ^[60]A1b.

Treatment selection must also accommodate disease-specific anatomy and comorbidity. A 10-year retrospective experience after radical cystectomy found that urinary diversion type was associated with differing late complications; ureterostomy patients were older and had more comorbidities and showed greater propensity for late urinary tract infection, nephrolithiasis, and psychological complications ^[237]. This evidence supports postoperative surveillance for stone disease in patients with urinary diversion, although it does not establish a comparative stone-prevention treatment.

Metabolic and cause-directed treatment

The treatment of calcium stones increasingly includes correction of an underlying endocrine disorder. Primary hyperparathyroidism is a recognized cause of calcium-containing nephrolithiasis, and parathyroidectomy is the only curative treatment for the metabolic disease ^[92]A1a. A 2026 systematic review of 13 studies—including prospective and retrospective cohorts and one randomized study—specifically evaluated whether parathyroidectomy reduces stone recurrence after successful treatment of primary hyperparathyroidism ^[92]A1a. A separate retrospective study of 306 patients with parathyroid adenomas examined 24-hour urinary calcium as a disease-specific predictor of stones and its relationship to surgical decision-making, reflecting continuing uncertainty about whether urinary calcium alone should determine intervention ^[179]B3b.

Normocalcemic primary hyperparathyroidism has also influenced the evolution of surveillance-based treatment. In a multicenter retrospective cohort of 527 patients followed for 3 years, investigators assessed progression to hypercalcemia, hypercalciuria, kidney stones, bone loss, and fractures ^[300]C. These findings are relevant because patients with apparently mild biochemical disease may require longitudinal reassessment rather than immediate stone-directed therapy alone. Conversely, autosomal dominant hypocalcemia type 1 may produce renal involvement and ectopic calcifications; a single-center series of 11 genetically confirmed adults evaluated renal, skeletal, cerebral, pregnancy, and treatment features ^[95]C4. Severe hyperparathyroid disease may present with recurrent stones and skeletal complications, as illustrated by a case of parathyroid carcinoma-associated hyperparathyroidism with recurrent nephrolithiasis and pathological fracture ^[301]C.

Pregnancy requires cause-directed treatment with special attention to maternal and fetal safety. Parathyroidectomy in the second trimester remains the standard treatment for primary hyperparathyroidism during pregnancy; microwave ablation has been reported only as an uncommon alternative when surgery is infeasible, contraindicated, or declined ^[96]C4.

Rare and genetic stone disorders

The treatment era has expanded to include molecular diagnosis and targeted therapy. Primary hyperoxalurias are autosomal-recessive disorders involving excessive hepatic oxalate production, and delayed diagnosis worsens prognosis ^[256]. In a French cohort, median diagnosis delay was 1.2 years in children versus 30 years in adults diagnosed between 2015 and 2019; the approval of the first RNA-interfering therapy in 2020 increased disease awareness and was evaluated for its effect on diagnostic delay ^[256]. Pediatric observational data from a high-prevalence region of India likewise used first-line metabolic testing, with stone analysis and whole-exome sequencing when indicated, demonstrating the movement toward genotype- and phenotype-directed treatment ^[262].

Prevention, adherence, and integrated follow-up

Prevention now depends not only on prescribing therapy but also on implementation. A multidisciplinary clinic involving endourologists, nephrologists, and dietitians prospectively assessed adherence among 100 high-risk stone formers receiving medical therapy ^[298]. A separate survey examined health literacy, counseling intensity, and quality of life in patients with nephrolithiasis in the context of AUA prevention guidance ^[224]C4. These studies reinforce the shift toward repeated education, individualized counseling, and multidisciplinary follow-up, particularly because adherence to preventive therapy is often poor ^[224]C4[298].

Comorbidity-aware prevention is increasingly important. Large prospective cohorts evaluated whether cardiovascular and bone events occur together in individuals with a history of kidney stone disease ^[247]. Population-based NHANES 2011–2020 data involving 31,566 adults examined the association between estimated glucose disposal rate—a surrogate for insulin resistance—and nephrolithiasis using multivariable modeling and propensity-score matching ^[297]. In ADPKD, a retrospective study of 42 adults assessed 24-hour urinary parameters in relation to kidney function and comorbidities, supporting individualized monitoring in patients at risk of chronic kidney disease ^[299]. By contrast, a case-control study of sialolithiasis—not renal stone disease—identified Sjögren syndrome as an associated condition, illustrating that salivary-stone findings should not be extrapolated to nephrolithiasis treatment ^[296].

Procedure selection and outcome targets

Selection among extracorporeal shock-wave lithotripsy (SWL), ureteroscopy (URS), and percutaneous nephrolithotomy (PCNL) should balance stone clearance, invasiveness, cost, hospital utilization, and patient-reported quality of life rather than relying on stone-free rate (SFR) alone. ^[111]A1a The 2026 AUA surgical-management guideline series is based on a staged systematic review of systematic reviews and primary literature concerning kidney and ureteral stone treatment. ^{[9]A1c[10]A1c[11]A1c} In practice, procedural planning should incorporate stone burden, location, anatomy, infection status, renal function, age, comorbidity, and the consequences of residual fragments. ^{[10]A1c[11]A1c}

Ureteroscopy and suction-assisted techniques

Flexible URS or retrograde intrarenal surgery (RIRS) remains a minimally invasive option for renal stones, but infection risk is a major procedural consideration. ^[282] In a multicenter single-arm study, flexible and navigable suction ureteral access sheath (FANS-UAS)-assisted RIRS under local anesthesia was evaluated in patients with stones ≤30 mm and persistent asymptomatic bacteriuria or pyuria despite antibiotic therapy; the study specifically addressed postoperative fever and urosepsis risk. ^[282] Because this evidence was noncomparative, it supports feasibility in a selected high-risk population rather than establishing superiority over standard URS or PCNL. ^[282]

Novel active-evacuation systems may extend the role of ureteroscopic treatment for larger renal stones. A retrospective study of CVAC steerable ureteroscopic renal evacuation (SURE) quantified stone size and volume on preoperative CT and assessed CT-defined Endourological Society stone-free status or a residual-fragment threshold of <5 mm on ultrasound or radiography; the study was designed to identify whether 3 cm represents an upper effective size boundary. ^[273] Evidence remains observational and single-surgeon, so the appropriate size limit for routine use is not established. ^[273]

In patients with a solitary kidney and stones >2 cm, a propensity-score-matched retrospective comparison evaluated FANS flexible URS against mini-PCNL using a hierarchical endpoint incorporating complications, 1-month SFR, and postoperative hospital stay. ^[270] These data support individualized selection when preservation of renal function and avoidance of complications are priorities, but the nonrandomized design limits causal comparison. ^[270] In children with 1–3 cm upper-tract stones, vacuum-assisted mini-PCNL using a 16-Fr sheath was compared retrospectively with FANS-RIRS using a 10/12-Fr sheath; reported SFRs were 97.3% and 91.3%, respectively, without a significant between-group difference in the available abstract. ^[292]

Percutaneous nephrolithotomy access and tract management

PCNL is an established approach for larger or complex renal calculi, and technical optimization includes tract dilation strategy, access guidance, drainage selection, and analgesia. ^[291] A systematic review and meta-analysis of fluoroscopy-guided conventional PCNL compared single-shot (“one-shot”) dilation with gradual multiple dilation, excluding ultrasound-guided, mini-, and micro-PCNL; the analysis therefore applies specifically to conventional fluoroscopic access and should not be generalized to other PCNL formats. ^[291]

For bilateral stone disease, synchronous bilateral PCNL has been compared with staged unilateral PCNL in an adult meta-analysis conducted according to PRISMA methods. ^[202]A1a The principal outcomes were SFR and Clavien–Dindo complication rates, making total stone clearance and cumulative morbidity central to counseling; patient selection, stone complexity, operative duration, infection risk, and institutional expertise should determine whether a synchronous approach is appropriate. ^[202]A1a

In selected patients with a solitary renal pelvic stone <3 cm, tubeless PCNL can be paired with local tract analgesia. ^[283] In a double-blind randomized trial of 120 adults, 20 mL of 0.25% bupivacaine infiltrated into the tract at the end of surgery was compared with no infiltration; 57 intervention and 56 control patients were analyzed for postoperative pain at 6, 12, and 24 hours. ^[283] This evidence supports a simple analgesic adjunct in the studied tubeless-PCNL population, but does not establish efficacy for multiple stones, larger stones, or standard tube-drained PCNL. ^[283]

Pediatric and technology-assisted procedures

For children younger than 6 years with renal stones measuring 1–2 cm, a prospective randomized trial directly compared mini-PCNL with SWL, reflecting the need to balance clearance, anesthesia exposure, tract morbidity, and repeat-procedure risk in a population with high recurrence-related morbidity. ^[60]A1b Low-profile single-use flexible ureteroscopes are also being explored in pediatric lithiasis; a preliminary retrospective series included 11 children undergoing 15 procedures, with a median stone size of 9 mm and a reported range of 5–27 mm. ^[272]C These small observational data expand technical experience but are insufficient to redefine pediatric guideline indications. ^[272]C

Robotic assistance is an emerging access technology. A preliminary prospective two-institution study evaluated robotic-assisted mini-PCNL combined with ureteroscopic lithotripsy using electromagnetic guidance for percutaneous access, with follow-up to 90 days. ^[293]C This may be relevant where independently obtaining percutaneous access is uncommon, but the early, limited study design does not establish comparative effectiveness or broad safety. ^[293]C

Special procedural contexts

Ex vivo back-table ureteroscopy and other stone-removal techniques during renal transplantation are being used to expand the potential donor pool. ^[269] A systematic review addressed feasibility, safety, stone characteristics, stone location, and techniques, but the evidence base consists of reported clinical experience and should be interpreted accordingly. ^[269] Imaging-assisted planning is also evolving: a systematic review found heterogeneous evidence for artificial-intelligence algorithms in ultrasound-based stone detection, classification, complication prediction, and procedural guidance, so AI should currently be regarded as an adjunct rather than a replacement for expert imaging interpretation or operative judgment. ^[2]D5

Overview

Nephrolithiasis may remain clinically silent, but an initially asymptomatic renal stone can subsequently cause renal colic or other pain, urinary obstruction, infection, stone enlargement, or the need for urological intervention. ^[14]A1a Recurrent stone disease is clinically important because it may result in kidney damage, sepsis, and invasive procedures. ^[136]A1a The risk and clinical significance of complications depend on stone burden and location, urinary drainage, infection status, comorbid disease, renal anatomy, and whether treatment is conservative or procedural. ^{[14]A1a[60]A1b[252]}

Obstruction, pain, infection, and renal injury

The principal natural-history complications are pain, obstruction, infection, and stone growth. ^[14]A1a Obstruction complicated by infection is potentially severe because infection-related complications include postoperative fever and urosepsis after endourological treatment. ^[282] In patients with acute pyelonephritis, renal impairment or renal-failure status at presentation and healthcare-exposure variables were evaluated as predictors of multidrug-resistant infection; these findings are relevant when infection accompanies obstructing stone disease, although the supplied study was not limited to nephrolithiasis. ^[304]C

Stone disease may contribute to progressive renal harm, particularly when recurrent, obstructing, infected, or associated with high-risk pediatric disease. ^{[136]A1a[60]A1b} In children, nephrolithiasis is described as having an elevated recurrence rate and elevated morbidity, with a risk of end-stage renal failure. ^[60]A1b The available evidence does not establish a single renal-function threshold at which a stone inevitably causes permanent injury; risk assessment therefore requires clinical, biochemical, and imaging follow-up. ^{[136]A1a[290]}

Recurrence and metabolic complications

Recurrence is a major long-term complication and is the focus of the 2026 American Urological Association medical-management guideline, whose stated purpose is to reduce recurrent disease in patients with a history of kidney stones. ^[290] A 2026 systematic review identified 31 intervention studies—26 randomized controlled trials and 5 nonrandomized studies—evaluating dietary, pharmacological, or surveillance approaches for recurrent nephrolithiasis; none evaluated imaging strategies. ^[136]A1a The URINE randomized trial compared empiric treatment with selective, 24-hour-urine-guided prevention in adults with recurrent idiopathic calcium stones, using dietary and fluid counseling plus indapamide and potassium citrate in the empiric arm. ^[303]

Primary hyperparathyroidism can be associated with calcium-containing stones despite hypercalciuria. ^[92]A1a Parathyroidectomy is the only curative treatment for the underlying endocrine disorder and is regarded indirectly as prophylaxis against recurrent stone formation; a systematic review of 13 studies evaluated recurrence after successful surgery and examined predictors of recurrence. ^[92]A1a Probiotic or synbiotic approaches targeting oxalate-degrading gut bacteria have been investigated as possible recurrence-prevention strategies for calcium oxalate stones, but the supplied review included only 9 studies and does not establish prevention as a routine treatment. ^[306]

Complications of stone procedures

Percutaneous nephrolithotomy (PCNL), retrograde intrarenal surgery, and shock-wave lithotripsy can be associated with postoperative complications, including infectious complications. ^{[60]A1b[112]A1a[202]A1a[252][277][282]} In a PCNL cohort, stone cultures were positive in 56% of patients and contained multiple organisms in 25%; the study specifically examined their relationship with postoperative complications. ^[277] Patients undergoing retrograde intrarenal surgery with persistent asymptomatic bacteriuria or pyuria despite antibiotic therapy were considered at high risk for postoperative urosepsis, and postoperative fever and sepsis were identified as the most severe complications of the procedure. ^[282]

Bilateral complex stone treatment may increase procedural exposure. Meta-analyses have compared same-session with staged bilateral PCNL and synchronous bilateral with staged unilateral PCNL, assessing stone-free outcomes, safety, efficiency, and Clavien–Dindo complication rates. ^{[112]A1a[202]A1a} The supplied abstracts do not provide pooled complication estimates; therefore, they cannot support a definitive claim that either bilateral strategy is universally safer. ^{[112]A1a[202]A1a} In children younger than 6 years with renal stones measuring <20 mm, a randomized trial compared mini-PCNL with shock-wave lithotripsy and evaluated efficacy and safety, in the context of pediatric recurrence and renal-failure risk. ^[60]A1b For ectopic pelvic kidneys, a multicenter study evaluated flexible ureteroscopy, multimodal image-guided PCNL, and laparoscopic pyelolithotomy using stone-free rate, ancillary procedures, and Clavien–Dindo complications. ^[252]

Special populations

Nephrolithiasis may complicate transplantation. Back-table stone removal during kidney transplantation has been studied as an ex vivo strategy to expand the donor pool; the literature review assessed safety, feasibility, stone characteristics, location, and removal techniques. ^[269] In renal-transplant recipients, a large stone-composition analysis included 69 transplant recipients among 33,616 urinary stone samples and compared their composition patterns with non-transplant stone formers. ^[236] Living kidney donors with asymptomatic stones have been evaluated for 10-year post-donation stone recurrence and estimated glomerular filtration-rate trajectories, although the supplied abstract does not report the outcome estimates. ^[305]

Urinary diversion can be followed by late urinary complications, including urinary tract infection and nephrolithiasis; in a cystectomy cohort, ureterostomy was associated with greater late UTI and nephrolithiasis propensity than other diversion contexts, although patients were also older and had more comorbidities. ^[237] Evidence concerning ketogenic diet therapy in infants under 2 years addresses epilepsy treatment rather than nephrolithiasis and should not be extrapolated to quantify stone complications. ^[257]

Clinical warning

Fever, systemic illness, or suspected infection with impaired urinary drainage should be treated as a potential urological emergency because infected obstruction can progress to sepsis. ^{[14]A1a[136]A1a[282]} Positive or polymicrobial stone cultures and persistent bacteriuria or pyuria identify settings requiring particular attention to perioperative infection risk. ^[277][282]

Overall prognosis

Nephrolithiasis is a highly recurrent condition affecting up to 15% of the global population, and recurrent episodes may result in pain, obstruction, infection, sepsis, renal damage, or invasive procedures. ^{[111]A1a[136]A1a} Prognosis is heterogeneous and depends on stone burden and location, urinary metabolic abnormalities, comorbid disease, age, anatomy, and adherence to preventive treatment. ^{[136]A1a[127]B3b[290]} The 2026 American Urological Association guideline frames long-term management around treatment and follow-up intended to reduce recurrent disease, rather than considering stone removal alone definitive therapy. ^[290]

Asymptomatic and residual renal stones

Many incidentally detected asymptomatic renal stones remain stable during surveillance, but a clinically important proportion subsequently develop pain, obstruction, infection, stone growth, or a need for intervention. ^[14]A1a Consequently, observation is often appropriate for asymptomatic stones, but prognosis should be individualized according to stone size, location, growth, urinary tract anatomy, infection risk, renal function, occupational or travel considerations, and patient preferences. ^[14]A1a[290] Current randomized-trial evidence directly comparing intervention with observation has been synthesized in a 2026 systematic review and meta-analysis; however, the abstract does not provide pooled event estimates, so precise probabilities of future symptoms or intervention cannot be assigned from the supplied evidence. ^[14]A1a

Surveillance strategies remain incompletely studied. A systematic review of recurrent-stone prevention identified 31 studies—26 randomized trials and 5 nonrandomized intervention studies—but none evaluated imaging strategies. ^[136]A1a Thus, the optimal imaging interval and the extent to which surveillance changes long-term renal or symptomatic outcomes remain uncertain on the available evidence. ^[136]A1a

Recurrence and prevention

Prevention is central to prognosis because recurrent disease can lead to repeated procedures and cumulative morbidity. ^{[136]A1a[290]} The 2026 prevention review evaluated dietary, pharmacologic, and surveillance interventions in adults and children, although all but three included studies enrolled adults and the supplied abstract does not report the intervention-specific recurrence effect sizes. ^[136]A1a The URINE randomized trial enrolled adults with recurrent idiopathic calcium stones and compared empiric treatment—dietary and fluid counseling plus indapamide and potassium citrate—with selective treatment guided by 24-hour urine results; urine testing was performed at baseline, 4 weeks, and 8 weeks, and the principal outcomes were calcium oxalate and calcium phosphate supersaturation. ^[303] The available abstract does not report clinical recurrence outcomes, so it does not establish whether either strategy produces superior long-term prevention of symptomatic stones. ^[303]

Family history may identify patients with increased inherited or shared environmental susceptibility. A stone-clinic study specifically examined whether family history predicted hypercalciuria, hyperoxaluria, hyperuricosuria, hypocitraturia, cystinuria, hypomagnesuria, or stone composition, but the supplied evidence does not provide the adjusted associations or recurrence rates. ^[127]B3b Long-term physical activity is also being evaluated as a potentially modifiable determinant: a U.S. cohort used Fitbit-derived steps, active minutes, and sedentary time to model incident stone risk in participants without prior stone disease, but the supplied abstract does not report hazard ratios. ^[250]

Comorbid and special-population prognosis

Primary hyperparathyroidism is a potentially reversible metabolic driver of calcium stones. Parathyroidectomy is the curative treatment for the underlying disorder and is regarded as a means of preventing recurrent stones; a systematic review included 13 studies—2 prospective cohorts, 10 retrospective cohorts, and 1 randomized study—of adults with treated primary hyperparathyroidism, documented nephrolithiasis, and at least 12 months of follow-up. ^[92]A1a The supplied abstract does not provide the pooled recurrence estimate or definitive predictors, so the magnitude and timing of benefit cannot be quantified here. ^[92]A1a

In children, nephrolithiasis is associated with an elevated recurrence burden and morbidity, including a reported risk of progression to end-stage renal failure; prognosis and treatment decisions are influenced by stone size, location, and composition. ^[60]A1b A prospective randomized trial in children younger than 6 years with 1–2-cm renal stones compared mini-percutaneous nephrolithotomy with shock-wave lithotripsy, but the provided abstract does not report comparative long-term recurrence, renal-function, or complication results. ^[60]A1b Pediatric flexible ureterorenoscopy is expanding, including use of single-use instruments smaller than 7 Fr, but evidence remains limited to preliminary experience; one retrospective series included 11 children, 15 procedures, and median stones of 9 mm with a range of 5–27 mm. ^[272]C

Patients with autosomal dominant polycystic kidney disease may have a distinct renal prognosis. A prospective cohort of 410 patients used baseline CT-confirmed collecting-system stones, excluding cyst-wall calcifications, and assessed initiation of renal replacement therapy; the supplied abstract does not report whether nephrolithiasis independently accelerated progression. ^[191]B2b Similarly, a prospective cohort of 1,497 Chinese patients with gout used serum urate, fractional urate excretion, gout duration, and stone burden to define clinical subtypes and evaluated progression to CKD stage ≥3, but the supplied abstract does not provide the subtype-specific hazard estimates. ^[248]

Procedural outcomes relevant to prognosis

Stone-free status is an important short-term endpoint, but prognosis should also incorporate complications, cost, length of stay, quality of life, and the likelihood of ancillary or staged procedures. ^[111]A1a Contemporary comparative studies evaluated flexible suction-assisted retrograde intrarenal surgery versus mini-PCNL for 2–3-cm stones, same-session versus staged bilateral PCNL, and suction-assisted flexible ureteroscopy versus mini-PCNL for stones >2 cm in solitary kidneys; these studies primarily address perioperative safety, stone-free rates, hospital stay, and composite outcomes rather than natural recurrence. ^{[101]A1a[112]A1a[270]} Pelvic-kidney stones likewise require individualized assessment because a multicenter study of 45 patients compared flexible ureteroscopy, image-guided PCNL, and laparoscopic pyelolithotomy using stone-free rate, ancillary procedures, and Clavien–Dindo complications as outcomes. ^[252]

Special surgical contexts may alter long-term risk. A systematic review describes ex-vivo stone removal during renal transplantation as an approach intended to expand the living or deceased donor pool, reflecting the historical concern that nephrolithiasis could be a relative contraindication to donation. ^[269] In a 10-year single-center retrospective study, carefully selected living donors with asymptomatic stones identified on predonation CT were compared with stone-free donors for postdonation recurrence and estimated GFR trajectories, although outcome estimates are not supplied in the abstract. ^[305] A large Chinese composition study analyzed 33,616 urinary stone samples, including 69 renal-transplant recipients, to characterize composition and comorbidity patterns; it informs etiologic assessment but does not establish recurrence or graft-survival probabilities. ^[236]

Practical prognostic interpretation

A single episode does not eliminate future risk. Patients with recurrent stones, metabolic abnormalities, strong family history, hyperparathyroidism, pediatric disease, gout, ADPKD, solitary kidneys, transplant-related disease, or complex urinary anatomy warrant structured metabolic evaluation and follow-up. ^{[127]B3b[191]B2b[248][290]} Available 2026 evidence supports shared decision-making for asymptomatic stones and prevention-focused follow-up, while emphasizing that exact natural-history probabilities and optimal imaging schedules remain incompletely defined. ^{[14]A1a[136]A1a[290]}

Children and adolescents

Pediatric nephrolithiasis warrants evaluation for recurrent, metabolic, medication-associated, and inherited causes because childhood stones may be associated with substantial recurrence, morbidity, and risk of chronic kidney disease (CKD) or kidney failure. ^{[60]A1b [249] [307]C} Evaluation should be tailored to age, stone burden, renal function, family history, and urinary abnormalities. Particularly important inherited or tubular disorders include primary hyperoxaluria, distal renal tubular acidosis (dRTA), Dent disease, and SLC34A1-related disorders, all of which may present with nephrolithiasis or nephrocalcinosis and can require long-term disease-specific management. ^{[234]C [235]C [249] [34]C4} Genetic testing can be diagnostically important when stones are early-onset, recurrent, bilateral, accompanied by nephrocalcinosis, CKD, growth abnormalities, hypophosphatemia, hypercalciuria, or a relevant family history. ^{[234]C [235]C [249] [307]C}

For renal stones measuring 1–2 cm in children younger than 6 years, a prospective randomized trial directly compared mini-percutaneous nephrolithotomy (mini-PCNL) with extracorporeal shock-wave lithotripsy (SWL), reflecting the need to balance stone clearance against procedural morbidity in very young children. ^[60]A1b The supplied abstract identifies stone size, location, and composition as factors guiding intervention but does not provide the trial’s comparative outcome data; treatment selection should therefore remain individualized. ^[60]A1b In children younger than 14 years with upper-tract stones measuring 1–3 cm, a retrospective matched comparison evaluated vacuum-assisted mini-PCNL using a 16-Fr sheath against flexible ureteroscopy with a flexible, navigable suction access sheath using 10/12-Fr sheaths. ^[292] The reported stone-free rates were 97.3% for vacuum-assisted mini-PCNL and 91.3% for the ureteroscopic approach, although the study was retrospective and comparative procedural outcomes must be interpreted in that context. ^[292]

Cystine stones in children are characterized by high recurrence and repeated procedural requirements; a 25-year institutional experience evaluated PCNL outcomes, complications, recurrence patterns, and long-term renal outcomes, while emphasizing the importance of adherence to medical therapy for renal prognosis. ^[309]C Children receiving ketogenic or modified Atkins diets for drug-resistant epilepsy may develop nephrolithiasis; a tertiary-center cohort of 112 children initiating dietary therapy assessed incidence, risk factors, clinical characteristics, management, and outcomes. ^[255]C Ceftriaxone is another pediatric medication-related concern: a systematic review and meta-analysis specifically assessed the pooled frequency of ceftriaxone-induced urolithiasis, distinguishing urinary stones from the better-recognized phenomenon of biliary pseudolithiasis. ^[64]A1a

Inherited and metabolic disorders

Primary hyperoxaluria causes excessive endogenous oxalate production and may lead to nephrolithiasis, nephrocalcinosis, and kidney failure. ^{[256] [234]C [307]C} In a national Turkish pediatric registry, the median age at diagnosis for primary hyperoxaluria type 1 was 2.6 years, the approximate diagnostic delay was 2 years, and 49.4% of patients had kidney failure at diagnosis; genetic diagnosis was performed in 71.1% of the cohort. ^[307]C A Tunisian genetically confirmed cohort further examined clinical and molecular features and minimum observed prevalence in a setting with substantial consanguinity. ^[234]C These data support early recognition and genetic confirmation in children with severe, recurrent, or early-onset calcium oxalate stone disease. ^{[234]C [256] [307]C}

Prospective European registry data address dRTA, a disorder associated with metabolic acidosis, growth failure, nephrocalcinosis, nephrolithiasis, and CKD. ^[249] The registry collected growth, creatinine, plasma and urine biochemistry, genetics, treatment, and clinical manifestations from February 2019 through May 2024, providing longitudinal evidence relevant to metabolic control and renal outcomes. ^[249] SLC34A1 variants produce a spectrum that includes infantile hypercalcemia type 2, nephrolithiasis/osteoporosis-hypophosphatemia type 2, and Fanconi renotubular syndrome type 2; a pediatric case series evaluated clinical, biochemical, molecular characteristics and response to oral phosphate therapy. ^[34]C4 Dent disease, caused by pathogenic variants in CLCN5 or OCRL1, is an X-linked tubular disorder with variable presentation and potential underdiagnosis; a Korean multicenter cohort included 48 genetically confirmed male patients from 44 unrelated families, with a median diagnosis age of 6.8 years. ^[235]C

Chronic hypoparathyroidism is associated with impaired renal calcium reabsorption, persistent hypercalciuria, nephrolithiasis, nephrocalcinosis, and CKD. ^[212]A1a A systematic review and exploratory meta-analysis evaluated thiazide therapy in adults with chronic hypoparathyroidism for reduction of urinary calcium and renal safety; because the evidence base was described as limited and included randomized and observational studies, treatment requires monitoring of renal function and biochemical response. ^[212]A1a

Patients with CKD, solitary kidneys, or kidney donation

Patients with a solitary kidney and stones larger than 2 cm represent a high-stakes population in which preservation of renal function and avoidance of complications are central. ^[270] A propensity-score-matched study compared flexible ureteroscopy using a flexible, navigable suction access sheath with mini-PCNL and used a hierarchical outcome incorporating complications, 1-month stone-free rate, and postoperative hospital stay. ^[270] The study was retrospective; its findings should inform, but not replace, individualized selection based on stone anatomy, renal function, surgical risk, and local expertise. ^[270]

In carefully selected living kidney donors with asymptomatic nephrolithiasis identified on predonation CT, a 10-year single-center retrospective cohort evaluated postdonation stone recurrence and eGFR trajectories compared with stone-free donors. ^[305] Donor evaluation should therefore consider stone burden and recurrence risk alongside long-term renal functional outcomes, although the supplied abstract does not provide the study’s numerical results. ^[305] In gout, stone burden formed one of four variables used to define clinical clusters in a prospective cohort of 1,497 Chinese patients; the study assessed progression to CKD stage ≥3 and explored the contribution of genetic risk to renal outcomes. ^[248]

Pregnancy

The supplied references do not provide pregnancy-specific data on nephrolithiasis diagnosis, imaging, analgesia, medical expulsive therapy, ureteroscopy, SWL, PCNL, or medication safety. Accordingly, pregnancy-specific recommendations cannot be updated from this reference set without extrapolation beyond the available evidence. Pediatric, inherited-metabolic, CKD, and drug-associated findings should not be assumed to apply directly to pregnancy. ^{[60]A1b [212]A1a [249] [255]C [307]C}

Environmental and neonatal considerations

A systematic review and meta-analysis across populations of varying age, sex, ethnicity, and geography evaluated the association between ambient temperature and renal colic, addressing extreme temperature as a potential population-level risk modifier. ^[213]B2a Preterm infants may also have medication-associated renal mineral complications: a population-pharmacokinetic and exposure-safety study of 51 infants born at 23–28.9 weeks’ gestation assessed simulated furosemide exposure in relation to ototoxicity, nephrocalcinosis, and nephrolithiasis. ^[161]B2b These findings support heightened clinical attention to renal imaging and mineral complications when vulnerable infants receive prolonged or intensive diuretic therapy, while recognizing that the study evaluated exposure–safety relationships rather than establishing a universal dosing threshold. ^[161]B2b

Scope and principles

Prevention should be individualized according to stone history, composition, metabolic abnormalities, comorbidities, age, kidney function, and patient preferences; the 2026 AUA guideline specifically addresses treatment and follow-up of patients with a history of kidney stones to reduce recurrence. ^[290] The most comprehensive recent systematic review identified 31 intervention studies (26 randomized trials and 5 nonrandomized studies), almost all in adults, but found no studies evaluating imaging strategies for recurrence prevention. ^[136]A1a Consequently, dietary and pharmacologic prevention have substantially more direct trial evidence than the optimal frequency or modality of surveillance imaging. ^[136]A1a

Primary prevention and lifestyle

Observational and randomized evidence supports attention to modifiable dietary and lifestyle factors for primary prevention, although the magnitude and certainty of associations vary across exposures and study designs. ^[310] Prevention counseling should therefore emphasize sustained lifestyle modification rather than reliance on a single dietary intervention. ^[310] The 2026 systematic review evaluated diet and pharmacologic therapy in adults and children, but almost all included studies enrolled adults and only three included children. ^[136]A1a

For patients with recurrent stones, preventive management should be linked to stone analysis and metabolic assessment where available, because treatment effects differ by stone phenotype and urinary abnormality. ^[136]A1a Evidence synthesized in recent umbrella and systematic reviews includes non-surgical medical approaches for prevention and stone management, but heterogeneity among interventions and outcomes limits uniform conclusions for every patient group. ^[220]A1a

Pharmacologic prevention

Thiazide and thiazide-like diuretics remain important options for recurrent calcium stone prevention, particularly when hypercalciuria is present, but recent evidence has challenged the assumption that all doses and agents have equivalent benefit. ^{[195]A1a[221]A1a} A 2025 network meta-analysis compared different thiazide and thiazide-like regimens using clinical or radiological recurrence as the primary endpoint and adverse effects as a secondary endpoint. ^[195]A1a An updated meta-analysis restricted to randomized placebo-controlled trials further evaluated thiazides for recurrent calcium oxalate stones and addressed uncertainty regarding optimal prescribing in hypercalciuric patients. ^[221]A1a These findings support selective, monitored use rather than automatic treatment of every stone former. ^{[195]A1a[221]A1a}

The broader evidence base includes pharmacologic and dietary interventions for recurrent nephrolithiasis, but the 2026 systematic review emphasized that evidence certainty differs across treatments and populations. ^[136]A1a Adverse effects and the patient’s metabolic profile should be considered when selecting preventive medication, because the thiazide literature specifically reports adverse effects as an important outcome. ^[195]A1a

Evaluation for secondary causes

Primary hyperparathyroidism is a clinically important secondary cause of nephrolithiasis. ^{[223]A1a[311]} In patients with mild asymptomatic primary hyperparathyroidism, randomized evidence comparing parathyroidectomy with active surveillance evaluated nephrolithiasis risk alongside skeletal outcomes and quality of life, but did not establish a universal benefit of surgery for every outcome. ^[223]A1a Contemporary guidance for sporadic primary hyperparathyroidism provides a framework for management in adults, although pregnancy was outside its scope. ^[311]

Among patients with primary hyperparathyroidism and previous nephrolithiasis, retrospective evidence found that parathyroidectomy was beneficial but not a complete guarantee against future stones. ^[314]C Separate retrospective evidence suggests that parathyroidectomy may slow renal-function decline in primary hyperparathyroidism. ^[315] These data support evaluation and treatment of clinically significant primary hyperparathyroidism while avoiding the expectation that surgery alone eliminates stone recurrence. ^[314]C[315]

Rare inherited or tubular disorders should be considered in selected patients, particularly those with early-onset, severe, recurrent, familial, or atypical disease. ^[34]C4 A pediatric case series described SLC34A1-related disorders causing renal tubular phenotypes that include nephrolithiasis, hypophosphatemia, hypercalcemia, and osteoporosis; oral phosphate therapy and genotype–phenotype assessment were explored, but the evidence was limited by the small series size. ^[34]C4

Asymptomatic stones: observation and intervention

Incidentally detected asymptomatic renal stones are increasingly recognized because of more widespread and sensitive imaging. ^{[14]A1a[77]B2a[313]} Many small asymptomatic or residual stones remain stable, but reported natural histories include stone growth, pain, obstruction, infection, emergency presentation, and subsequent intervention. ^[77]B2a[313] The appropriate choice between active stone-directed treatment and observation therefore depends on stone size and location, growth, anatomy, infection risk, renal function, occupational or travel considerations, symptoms, and patient preferences. ^{[14]A1a[77]B2a[313]}

A 2026 systematic review and meta-analysis of randomized trials directly compared intervention with observation for asymptomatic kidney stones because guideline-based care commonly favors surveillance for many such stones while emphasizing individualized shared decision-making. ^[14]A1a The available natural-history evidence supports surveillance as a reasonable strategy for selected asymptomatic patients, but it does not justify ignoring follow-up or assuming that all clinically silent stones are harmless. ^[77]B2a[313]

Imaging surveillance and special populations

No randomized intervention study identified in the 2026 prevention review evaluated an imaging strategy for preventing recurrent nephrolithiasis. ^[136]A1a Thus, surveillance imaging should be individualized, with modality and interval determined by clinical context and the need to detect growth, obstruction, infection, or loss of renal function. ^[136]A1a When CT is required for follow-up of known nephrolithiasis without symptoms, a kidney-limited unenhanced CT protocol can reduce scan length and radiation exposure compared with routine abdomen-and-pelvis coverage. ^[316]

Patients with a renal transplant require particular caution because they have a single functioning graft kidney, altered anatomy, immunosuppressive treatment, and relevant comorbidities. ^[222]A1a Evidence in transplant recipients has evaluated de novo stone prevalence, presentation, composition, and treatment, but remains substantially less robust than the evidence in the general stone-forming population. ^[222]A1a Stone composition may differ in transplant recipients, and targeted recurrence prevention should be based on composition and metabolic findings when available. ^[236]

Patients with spinal cord injury may also require individualized surveillance because prior urinary stone surgery is associated with patient-reported complications and quality-of-life considerations in this population. ^[69]B2b A urine biomarker study involving patients with nephrolithiasis was designed for bladder-cancer detection and surveillance, not kidney-stone screening or recurrence monitoring; its inclusion of nephrolithiasis among benign urological controls does not establish a role for urinary cancer biomarkers in stone surveillance. ^[312]

Practical follow-up

Follow-up should reassess symptoms, stone events, renal function, adherence, treatment tolerance, and relevant urinary risk factors, with imaging used selectively to monitor known asymptomatic or residual stones. ^{[136]A1a[290]} Shared decision-making is essential whenever observation and intervention are both clinically reasonable, especially because the benefits of prophylactic intervention must be balanced against procedure-related harms and the variable natural history of asymptomatic stones. ^{[14]A1a[77]B2a[313]}