Nephrolithiasis

Definition

Nephrolithiasis denotes urinary stone disease involving calculi within the kidney and, in clinical usage, is often used interchangeably with “kidney stones,” “renal stones,” or kidney stone disease (KSD). The cited literature also uses the broader terms “urinary stone disease” and “upper-tract urinary stone disease,” particularly when the kidney and ureter are considered together ^{[8]D5[230]D[231]D}. “Calcium nephrolithiasis” is a more specific term for calcium-containing stone disease and is the focus of a multidisciplinary consensus statement addressing metabolic diagnosis, prevention, and systemic manifestations ^[1]A1c.

The available references do not provide a single universally adopted anatomical, compositional, or pathophysiological classification system. They do, however, demonstrate that classification may be performed across several dimensions: anatomical location, stone composition, formation pattern, associated pathology, clinical complexity, imaging appearance, treatment modality, and postoperative complications ^{[1]A1c[2]D5[8]D5}. Stone composition and the pattern of stone formation may influence the clinical course, but the cited review emphasizes that their clinical relevance remains incompletely understood ^[8]D5.

Anatomical and clinical nomenclature

Anatomically, terminology should distinguish renal calculi from ureteral calculi when the site is known; “upper-tract urinary stone disease” encompasses stones in the kidney or ureter ^[230]D. “Nephrolithiasis” is therefore narrower than the general term “urinary stone disease” when ureteral or other urinary-tract sites are included ^[230]D. A “negative ureteroscopy” is a procedural term—not a disease subtype—defined as ureteroscopy undertaken with the intention of removing a kidney or ureteral stone in which no stone is ultimately removed. This may occur because the presumed stone has passed or because the presumed lesion was outside the collecting system ^[230]D.

The term “complex renal stone disease” is used clinically in relation to percutaneous nephrolithotomy (PCNL), although the cited study does not establish a formal compositional or anatomical definition of complexity ^[227]. PCNL is described as the standard treatment for complex renal stone disease in that study, while mini-PCNL uses smaller access sheaths of 14–20 F ^[227]. These treatment labels should not be mistaken for formal disease classifications.

Composition- and mechanism-oriented classification

Calcium nephrolithiasis represents a clinically important metabolic category addressed by consensus-based diagnostic and preventive recommendations ^[1]A1c. The consensus process included 27 clinical questions, review of 5,216 potentially relevant publications, and selection of 407 articles considered scientifically useful; statements were developed by working groups and approved after plenary discussion ^[1]A1c. The cited abstract does not provide a complete list of calcium-stone subtypes or biochemical thresholds, so specific compositional labels and laboratory cutoffs should be stated only when independently documented by stone analysis or metabolic evaluation ^[1]A1c.

A broader research-oriented classification may incorporate stone composition, formation pattern, and associated pathological features. Modern endoscopic imaging and micro-computed tomography were identified as technologies that can improve investigation of stone structure and composition, although the cited source does not define a validated nomenclature based on these modalities ^[8]D5.

Imaging and artificial-intelligence terminology

Ultrasound-based terminology may classify kidney-stone applications as detection, classification, prediction of complications or outcomes, and procedural guidance ^[2]D5. A 2026 systematic review assessed artificial-intelligence and deep-learning algorithms in these domains and emphasized that the evidence was heterogeneous ^[2]D5. Accordingly, an ultrasound or AI output should be described as an imaging-detection or prediction result rather than as a definitive etiological classification unless composition or clinical diagnosis has been independently established ^[2]D5.

Procedure- and outcome-related classification

Treatment-related nomenclature includes ureteroscopy (URS), extracorporeal shock-wave lithotripsy (SWL), and PCNL; national claims analyses have examined trends in these procedures and in the provider performing initial renal access for PCNL ^[229]D. Endoscopic technology may also be described by the imaging platform: the Endockscope combines a smartphone, lens system, and rechargeable light-emitting-diode source, and was evaluated against standard endoscopic equipment ^[7]D5. The reported approximate equipment costs were $45 for the Endockscope system versus $45,000 for the conventional camera and high-powered light source ^[7]D5. These are technology classifications, not stone classifications.

Complication nomenclature should be kept separate from nephrolithiasis classification. The five-grade Clavien system was used to categorize complications after 150 laparoscopic pyeloplasties ^[4]C4. In pediatric PCNL, the Clavien–Dindo system was compared with the pediatric-oriented Clavien–Madadi system in 270 procedures; the study reported strong correlation but only moderate agreement ^[317]. These systems classify treatment complications rather than stone composition, burden, location, or recurrence risk ^[4]C4[317].

Related disease burden and systemic context

Nephrolithiasis may be discussed in relation to obstruction, infection, renal impairment, and recurrent interventions. In patients with chronic kidney disease, the cited mini-PCNL study notes a reported urinary-stone prevalence of 3.2% in end-stage renal disease and evaluates postoperative renal outcomes in patients with CKD stage 3 or higher ^[227]. This association provides clinical context but does not establish CKD as a nephrolithiasis subtype. Similarly, urinary infection terminology should remain distinct from stone terminology; one outpatient study examined treatment duration for male urinary tract infection and found no clinical benefit to treatment longer than 7 days, but it did not classify nephrolithiasis ^[228]D.

Scope and documentation principles

Contemporary literature uses nephrolithiasis, kidney stones, renal stones, KSD, calcium nephrolithiasis, urinary stone disease, and upper-tract urinary stone disease with overlapping but nonidentical scopes ^{[1]A1c[8]D5[230]D[231]D}. A precise record should therefore specify: (1) anatomical site, (2) confirmed or suspected composition, (3) stone burden or complexity when relevant, (4) obstruction or infection status, (5) imaging modality and certainty, and (6) treatment and complication terminology. Epidemiological and service-planning studies may additionally use administrative diagnostic and procedural codes, as illustrated by analyses from England, Scotland, and population-based ureteroscopy datasets ^[231]D[230]D.

Overview

Nephrolithiasis is a heterogeneous disorder in which urinary supersaturation, impaired crystal handling, tubular injury, and host-specific metabolic or genetic factors interact to initiate and promote stone formation. Calcium oxalate is the predominant stone type, although calcium phosphate, uric acid, cystine, infection-related, and mixed stones arise through distinct biochemical pathways. ^[242] Stone formation is not necessarily bilateral: persistent unilateral nephrolithiasis may occur despite apparently similar systemic 24-hour urine profiles, indicating that kidney-specific factors may contribute in addition to systemic metabolic abnormalities. ^[318]

Urinary supersaturation and crystal retention

The immediate physicochemical prerequisite for crystallization is an excess of lithogenic solute relative to urinary solvent and inhibitors; the supplied studies identify altered urinary organic acids and inorganic ions as metabolically associated with calcium oxalate nephrolithiasis. ^[238] Machine-learning analysis of morning urine profiles was developed to stratify calcium oxalate risk, supporting the concept that urinary metabolite patterns may capture lithogenic susceptibility beyond conventional single-analyte assessment. ^[238] Low fluid intake increases lithogenic concentration; in men with symptomatic benign prostatic hyperplasia, fluid restriction to control lower urinary tract symptoms was proposed as a mechanism contributing to increased stone risk. ^[233]

Crystal formation may be facilitated by nephrocalcinosis and parenchymal mineralization. In feline kidneys, high-resolution microradiography was used to examine the association between nephrolithiasis and striated or punctate nephrocalcinosis, providing an experimental model for the relationship between intraparenchymal mineral deposition and urinary stones. ^[239] However, animal models of hyperoxaluria do not reproduce the full complexity of human disease, and their mechanistic or therapeutic findings require species- and model-specific interpretation. ^[325]D

Tubular epithelial injury and crystal–cell interactions

Calcium oxalate crystals can activate stress and cell-death pathways in renal tubular epithelial cells. Experimental work links serine metabolism to endoplasmic-reticulum stress, reactive oxygen species generation, and apoptosis; a serine–SDSL–IDH2 axis was proposed to attenuate these responses and protect against calcium oxalate crystallization. ^[242] A related experimental study identified mitochondrial dysfunction as a central link between metabolic syndrome and lithogenic susceptibility: impaired mitochondrial biogenesis and excessive mitochondrial reactive oxygen species in tubular epithelial cells were associated with activation of inflammatory and injury pathways. ^[322]D

Lipotoxicity is another proposed component of tubular damage. In nephrolithiasis models, FABP1-mediated lipid metabolic reprogramming was investigated as a mechanism that buffers lipotoxicity and preserves PPARγ activity; kidney-specific Fabp1 knockdown, patient specimens, transcriptomics, metabolomics, co-immunoprecipitation, and reporter assays were used to examine this pathway. ^[323]D These findings support a model in which tubular metabolic failure may amplify crystal-associated injury, although the cited evidence is primarily experimental and does not establish FABP1-directed treatment in humans. ^[323]D

Gut–kidney and microbiome-associated mechanisms

Intestinal metabolism can modify oxalate handling. In rat and Drosophila models, adenine enrichment was associated with disruption of intestinal architecture, reduced tight-junction proteins, altered expression of the oxalate transporters SLC26A3 and SLC26A6, increased net enteric oxalate absorption, and enhanced calcium oxalate deposition. ^[321]D A separate multi-omics study identified isoallolithocholic acid as a microbiota-associated bile acid increased in feces, serum, kidney, and urine in calcium oxalate stone models and in examined individuals. ^[327]D Isoallolithocholic acid interacted with PARP1, while PARP1 knockdown or pharmacologic inhibition reduced crystal deposition, tubular injury, and mitochondrial dysfunction in experimental systems. ^[327]D

Genetic and systemic metabolic mechanisms

Inherited disorders can produce stone formation through defined tubular or enzymatic defects. Primary hyperoxaluria type 1 results from pathogenic AGXT variants and causes endogenous oxalate overproduction; its clinical burden may be increased in populations with substantial consanguinity. ^[234]C Cystinuria results from impaired proximal tubular reabsorption of cystine, most commonly involving SLC3A1 or SLC7A9, with PBX1 variants reported in specific populations; circulating microRNAs are being investigated as biomarkers of disease severity. ^[319]C Dent disease type 1 results from pathogenic CLCN5 variants, whereas Dent disease type 2 involves OCRL1; loss of ClC-5 disrupts receptor-mediated endocytosis and is associated with low-molecular-weight proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis, and progressive kidney failure. ^[235]C[241]C

Hyperuricemia is linked to renal injury, tubulointerstitial fibrosis, and uric acid nephrolithiasis. ^[326]D Experimental work with a Panax quinquefolius fructan evaluated effects on hyperuricemia, renal transporters, intestinal barrier integrity, and gut microbiota, but these findings represent preclinical therapeutic investigation rather than established human stone-prevention therapy. ^[326]D

Obstruction, inflammation, and clinical expression

A stone may remain asymptomatic or subsequently cause pain, obstruction, infection, growth, or a need for intervention; current evidence supports individualized surveillance or intervention decisions for asymptomatic stones rather than assuming uniform progression. ^[14]A1a Acute upper urinary tract obstruction can cause acute kidney injury, and a prospective observational study examined circulating endocannabinoid changes before and after relief of obstruction, reflecting possible links among renal hemodynamics, inflammation, and acute renal dysfunction. ^[232]C Evidence from feline subcutaneous ureteral bypass experience also illustrates that urinary obstruction and positive urine cultures are clinically important complications, although that study concerns device management rather than primary human stone pathogenesis. ^[320]C

Evidence limitations

Renal-transplant recipients may have distinct urological and metabolic environments; a large retrospective stone-composition study compared transplant recipients with non-transplant stone formers, but composition associations do not by themselves prove causal mechanisms. ^[236] In-vitro suction-access-sheath studies address stone clearance and intrarenal pressure control, not stone initiation or recurrence biology. ^[324]D Overall, the strongest emerging mechanistic themes are urinary supersaturation, intestinal oxalate handling, tubular mitochondrial and lipid stress, epithelial apoptosis, genetic tubular transport defects, and microbiome-derived signaling, but several pathways remain supported chiefly by observational or experimental evidence. ^{[238][242][321]D[322]D[323]D[327]D}

Epidemiology

Nephrolithiasis is a recurrent, multifactorial disorder whose incidence has increased globally in recent decades. Pediatric disease is clinically important because recurrence and morbidity are substantial, and recurrent or severe disease may contribute to progression toward end-stage renal failure. ^[60]A1b Contemporary evidence also links kidney-stone disease (KSD) with broader systemic outcomes: prospective cohort data have evaluated cardiovascular and bone events occurring after stone disease, supporting the concept that KSD may share pathogenic pathways with cardiometabolic and skeletal disorders. ^[247]

The available updated literature does not provide a single global prevalence estimate in the cited studies, but it demonstrates clinically relevant disease across pediatric, adult, endocrine, genetic, environmental, and postoperative populations. Pediatric stones may occur early in life, including among children younger than 6 years, and are sufficiently recurrent and morbid to require dietary, pharmacological, or urological management. ^[60]A1b Among adults, stone risk is influenced by inherited susceptibility, metabolic abnormalities, hydration, climate, activity, comorbidity, medication exposure, and urinary tract reconstruction. ^{[65]A1a[127]B3b[233][237]}

Etiology and pathophysiology

Stone formation results from urinary supersaturation and crystallization in the setting of altered urinary composition, reduced urine volume, or urinary stasis. Higher ambient temperatures may increase stone-related events through dehydration and physiological changes including increased urinary calcium excretion and greater calcium oxalate or calcium phosphate supersaturation. ^[65]A1a Kidney disease-associated nephrolithiasis has been associated with higher urinary calcium/creatinine and magnesium/creatinine ratios and lower citrate/creatinine ratios and urinary uric acid levels than common stone-forming disease, suggesting that impaired renal function may modify the urinary lithogenic profile. ^[335]

Inherited disorders are important causes of early-onset, recurrent, or severe stones. Primary hyperoxaluria type 1 is an autosomal-recessive disease caused by pathogenic variants in AGXT; its burden may be increased in populations with high consanguinity, and affected patients may present during childhood. ^[234]C Family history is associated with metabolic abnormalities and may help predict stone composition; evaluated abnormalities included hypercalciuria, hyperoxaluria, hyperuricosuria, hypocitraturia, cystinuria, and hypomagnesuria. ^[127]B3b Genetic susceptibility also modifies environmental and lifestyle associations: in a UK Biobank cohort, investigators assessed nephrolithiasis incidence according to an oxidative balance score and a polygenic risk score based on 20 single-nucleotide polymorphisms. ^[67]B2b

Endocrine and metabolic disease can promote lithogenesis. Primary hyperparathyroidism is represented in the updated literature as a disorder with renal involvement and skeletal complications, while permanent hypoparathyroidism is associated with treatment-related mineral abnormalities; in a cohort of 958 adults with permanent hypoparathyroidism, hypercalciuria occurred in 44.4% and nephrolithiasis or nephrocalcinosis in 13.5%. ^[251][254] Gout and hyperuricemia may also be relevant: a prospective cohort of 1,497 Chinese patients with gout incorporated serum urate, fractional uric-acid excretion, gout duration, and kidney-stone burden when evaluating chronic kidney disease progression. ^[248]

Modifiable and environmental risk factors

Hydration is a central modifiable determinant. Symptomatic benign prostatic hyperplasia may increase stone risk because affected men may restrict fluid intake to control lower urinary tract symptoms; this association was evaluated in a nationwide cohort of men aged 45–85 years. ^[233] Conversely, higher long-term physical activity may be protective: wearable-device data from the All of Us program evaluated daily steps, active minutes, and sedentary time in participants without previous stones. ^[250]

Climate exposure is an increasingly relevant population-level risk factor. A systematic review identified 46 studies, with 16 included in meta-analysis; most reported a positive association between higher ambient temperature and kidney-stone-related events. ^[65]A1a Diet and lifestyle may influence oxidative balance and inherited risk, although the cited cohort evaluated association rather than proving causality. ^[67]B2b A higher serum apolipoprotein B/albumin ratio, a marker integrating atherogenic lipid burden with nutritional and inflammatory status, was investigated as a risk marker in a Chinese cohort of 741 individuals and an NHANES validation population of 12,108 adults. ^[337]

Medication, environmental, and anatomic factors should also be considered. Ceftriaxone can produce urinary calculi in children; a 2026 systematic review and meta-analysis specifically estimated the pooled frequency of ceftriaxone-induced urolithiasis, distinguishing it from biliary pseudolithiasis and urinary calcifications that are often combined in earlier reports. ^[64]A1a Urinary diversion after radical cystectomy is associated with late complications including urinary tract infection and nephrolithiasis, with ureterostomy patients described as older and more comorbid in a 10-year institutional study. ^[237] Higher urinary glyphosate concentrations were associated with nephrolithiasis in NHANES analysis; each unit increase in log-transformed urinary glyphosate was associated with 25% higher odds of stones (OR 1.25, 95% CI 1.06–1.47), although this observational association does not establish causation. ^[240]

Clinical risk assessment

Risk assessment should integrate age at onset, recurrence, family history, stone composition, dietary and fluid behavior, climate exposure, metabolic and endocrine disease, kidney function, medication history, urinary anatomy, and possible inherited disease. ^{[60]A1b[64]A1a[65]A1a[127]B3b[234]C[237][335]} Because the cited studies include randomized, cohort, retrospective, cross-sectional, and systematic-review designs, associations should be interpreted according to study design; several newer biomarkers and environmental factors remain hypothesis-generating rather than established causal determinants. ^{[64]A1a[67]B2b[237][240][337]}

Overview

Nephrolithiasis may present with acute renal or ureteric colic, hematuria, urinary obstruction, recurrent stone episodes, or nonspecific findings discovered during imaging; however, stones may also remain clinically silent despite substantial stone burden. In a pediatric series of children with enamel renal syndrome, all patients had multiple bilateral kidney stones and one family had nephrocalcinosis, yet none reported microscopic or macroscopic hematuria or renal colic. ^[97]C4 Pediatric nephrolithiasis may therefore be identified incidentally during evaluation of an associated disorder or through screening rather than through classic acute pain. ^[97]C4[263]C

Acute symptomatic presentation

The typical symptomatic presentation is flank or abdominal pain attributable to ureteral passage or obstruction, often accompanied by hematuria; emergency-department studies commonly evaluate patients presenting with flank pain when nephrolithiasis is suspected. ^[340] In children, hematuria is regarded as one of the most frequent diagnostic markers of nephrolithiasis, although its relationship to stone characteristics and severity is not uniform. ^[258] The pediatric hematuria study specifically evaluated children with nephrolithiasis or nephrocalcinosis while excluding active urinary infection, acute obstruction, recent renal colic, trauma, fever, urinary tract tumors, genitourinary anomalies, systemic disease, and familial hematuria; consequently, hematuria may be clinically useful even when infection or acute obstruction is not present. ^[258]

Pain and hematuria are not obligatory. Children with genetically determined or metabolic stone disease may have bilateral stones, nephrocalcinosis, or progressive renal involvement without colic or visible urinary blood. ^{[97]C4[262][263]C} In the reported FAM20A-associated enamel renal syndrome cohort, referral occurred through a specialized dental team at a median age of 14.5 years (range 11–19 years), illustrating that the renal phenotype may be detected through extra-renal manifestations rather than urinary symptoms. ^[97]C4

Pediatric and early-onset disease

Pediatric nephrolithiasis is clinically heterogeneous and may reflect interacting genetic, metabolic, and environmental factors. ^[262] A prospective study from northwestern India evaluated children younger than 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] Nephrocalcinosis has a particularly early presentation: in a tertiary children’s-hospital series, 50% of affected children were younger than 2 years, and congenital disorders were identified in 54%; renal tubular acidosis accounted for 44% of the underlying causes reported in that cohort. ^[263]C

Rare inherited disorders can present across the lifespan. CYP24A1-related infantile hypercalcemia type 1 ranges from severe infantile disease with hypercalcemia, dehydration, and vomiting to milder adult disease first recognized during evaluation of recurrent nephrolithiasis or nephrocalcinosis. ^[338]C Primary hyperoxalurias are autosomal-recessive disorders causing excessive hepatic oxalate production, and delayed recognition is a major determinant of prognosis; in a previously reported French cohort, diagnosis delay was 1.2 years in children versus 30 years in adults. ^[256]

Metabolic and systemic presentations

Nephrolithiasis may be a renal manifestation of primary hyperparathyroidism, although calcium-containing stones are described as an infrequent complication despite hypercalciuria. ^[92]A1a Contemporary primary hyperparathyroidism cohorts may include asymptomatic patients, but clinically overt renal and skeletal complications remain observed in some settings. ^[254] In pregnancy, hyperparathyroidism and other causes of gestational hypercalcemia may be clinically nonspecific and can mimic common pregnancy-related symptoms; maternal nephrolithiasis and pancreatitis are recognized complications. ^[96]C4[341]D

Primary hyperparathyroidism during pregnancy is rare, with an estimated prevalence of less than 1% among pregnant women, and may be associated with serious maternal and fetal complications even when maternal symptoms are limited. ^[96]C4 Gestational hypercalcemia is described as rare but potentially life-threatening; reported obstetric consequences include fetal loss, fetal growth restriction, preeclampsia, and preterm delivery, while severe neonatal hypocalcemia may cause tetany or death. ^[341]D

Other systemic disorders may coexist with or predispose to stone disease. Sarcoidosis can dysregulate vitamin D metabolism and thereby alter calcium homeostasis, providing a biologically plausible link to nephrolithiasis; this association has been evaluated in a large cohort of US Black women. ^[339] Tumor-induced osteomalacia may be masked by coexisting hypercalcemic primary hyperparathyroidism; a reported patient presented with fragility fractures, generalized bone pain, and nephrolithiasis. ^[94]C4 Autosomal dominant hypocalcemia type 1 is also characterized by potential renal involvement and ectopic calcifications, although the cited series was designed primarily to characterize the disorder rather than define nephrolithiasis-specific symptoms. ^[95]C4

Recurrence and risk-context clues

Recurrent nephrolithiasis should prompt consideration of persistent metabolic disease, inherited disorders, and modifiable urinary risk factors. A systematic review of adults with surgically treated primary hyperparathyroidism specifically examined stone recurrence after parathyroidectomy and sought predictors of recurrent stone formation; eligible patients had documented nephrolithiasis and at least 12 months of follow-up. ^[92]A1a Symptomatic benign prostatic hyperplasia may also be relevant in older men because lower-urinary-tract symptoms can lead patients to restrict fluid intake, a behavior investigated as a potential contributor to kidney-stone incidence in men aged 45–85 years. ^[233]

Clinical interpretation

The absence of colic or hematuria does not exclude clinically important nephrolithiasis, particularly in children, patients with nephrocalcinosis, and those with inherited or systemic mineral-metabolism disorders. ^{[97]C4[256][262][263]C[338]C} Conversely, flank pain or hematuria is not specific for a stone and should be interpreted alongside infection, obstruction, systemic disease, pregnancy status, and imaging findings. ^[258][340]

Diagnostic objectives

The diagnostic evaluation of nephrolithiasis should establish whether a urinary calculus is present, define its burden and location, identify obstruction or infection, assess renal function, and determine recurrence risk or an underlying systemic, medication-related, or genetic cause. The supplied evidence is weighted toward selected clinical populations and does not provide a new universal diagnostic algorithm; therefore, test selection should be individualized according to symptoms, imaging findings, age, comorbidity, renal anatomy, and recurrence history. ^[14]A1a

Clinical assessment and risk stratification

History should document renal colic, hematuria, urinary symptoms, fever, prior stones or procedures, solitary kidney or transplantation, family history, medication exposures, and dietary or environmental risks. This is clinically important because asymptomatic stones may remain stable but can subsequently produce pain, obstruction, infection, growth, or intervention; surveillance and shared decision-making are therefore appropriate considerations when an incidentally detected stone is not causing complications. ^[14]A1a

Family history is relevant to metabolic and etiologic assessment. In a specialized stone-clinic cohort, patients with a family history were evaluated for hypercalciuria, hyperoxaluria, hyperuricosuria, hypocitraturia, cystinuria, hypomagnesuria, and stone composition, although the supplied abstract does not provide the complete effect estimates. ^[127]B3b Children or adults with recurrent stones, nephrocalcinosis, early-onset disease, unexplained chronic kidney disease, or a strong family history should prompt consideration of inherited disorders. Primary hyperoxaluria type 1 is caused by pathogenic variants in AGXT, whereas Dent disease is associated with pathogenic variants in CLCN5 or OCRL1 and may be underdiagnosed because of variable manifestations. ^[234]C[235]C

Medication and exposure history should include ceftriaxone, particularly in children. A 2026 systematic review specifically evaluated urinary urolithiasis after ceftriaxone exposure and distinguished it from the more commonly discussed biliary pseudolithiasis; the pooled-frequency estimate should be consulted when assessing a child with compatible urinary calcification or obstruction. ^[64]A1a Environmental context may also be relevant: most studies in a systematic review reported a positive association between higher ambient temperature and kidney-stone-related events, including acute renal colic. ^[65]A1a

Imaging

Imaging confirmation is central, particularly because improved imaging has increased detection of asymptomatic renal stones. ^[14]A1a The available evidence does not specify a preferred first-line modality or radiation protocol. Imaging should document stone number, maximal dimensions, laterality, renal location, collecting-system dilatation, and relevant anatomic abnormalities; these characteristics are also necessary for subsequent management comparisons involving renal stones up to 2 cm, stones >2 cm, and pediatric stones measuring 1–3 cm. ^{[329][270][292]}

When infection is suspected in a patient with nephrolithiasis, routine clinical and laboratory assessment remains essential. An exploratory multicenter study evaluated 18F-FDG PET/CT for kidney-stone-associated renal infection in 120 lung-cancer patients with radiologically confirmed nephrolithiasis and correlated PET/CT measurements with stone burden and inflammatory cytokine profiles; this specialized technique should not be considered routine diagnostic imaging on the basis of that retrospective evidence. ^[271]

Laboratory and metabolic evaluation

Laboratory workup should assess renal function and look for infection or metabolic abnormalities. The supplied evidence directly identifies 24-hour urine calcium, citrate, and urine pH as clinically meaningful variables: one propensity-matched study excluded patients with urine pH ≤6, 24-hour urine calcium ≥250 mg, or 24-hour urine citrate ≤320 mg when constructing an empiric-treatment cohort. These values are study eligibility thresholds rather than validated universal diagnostic cutoffs, but they illustrate the abnormalities that should be sought during metabolic evaluation. ^[330]

Stone analysis is important when material is available. A large observational analysis used Fourier-transform infrared spectrometry to characterize 33,616 urinary stone samples, including samples from renal-transplant recipients, and examined differences in composition and comorbidity profiles between transplant and non-transplant populations. ^[236] In selected recurrent or atypical calcium oxalate stone formers, morning-urine organic acids and inorganic ions combined with machine-learning models were investigated for risk stratification; this remains an emerging research approach and should not replace established metabolic evaluation. ^[238]

Additional phenotyping may be useful in research or selected patients. CT-derived visceral-to-subcutaneous fat ratio was studied in 308 adults with nephrolithiasis in relation to 24-hour urinary calcium excretion, with modification by physiologic age. ^[331] Estimated glucose disposal rate was evaluated as a marker associated with nephrolithiasis history in 31,566 US adults from NHANES 2011–2020, but this association does not establish a diagnostic test for an individual patient. ^[297] In adults with chronic hypoparathyroidism, palopegteriparatide treatment was associated with renal-function outcomes over 104 weeks; this evidence concerns treatment follow-up rather than stone diagnosis, but calcium-phosphate disorders should remain part of the medical context when evaluating stones. ^[328]

Scope and evidence limitations

The remaining supplied studies primarily compare observation with intervention or compare ESWL, ureteroscopy, suction-assisted ureteroscopy, and PCNL; they inform treatment selection rather than diagnostic testing. ^{[14]A1a[111]A1a[329][292][270][269][272]C} Evidence on back-table stone removal during transplantation likewise concerns ex-vivo management, not initial diagnosis. ^[269] A study of ketogenic diet therapy in infants addressed epilepsy outcomes and does not provide nephrolithiasis diagnostic evidence. ^[257]

Clinical severity and urgent obstruction

Acute obstructive uropathy should be treated as a potentially life-threatening presentation because it may be accompanied by acute renal failure or sepsis, and prompt attention is important to prevent further clinical deterioration ^[121]A1c. Severity assessment should therefore integrate symptoms, imaging evidence of obstruction, renal function, and infection rather than relying on stone size alone ^[121]A1c. When urgent decompression is required, treatment options include conservative medical management in selected patients, retrograde ureteral stenting, or percutaneous nephrostomy/nephroureteral catheter placement, with the choice guided by the clinical scenario and need for consultation ^[121]A1c.

Imaging-based staging and anatomic burden

Imaging is central to defining stone burden, location, obstruction, and complications; ultrasound and CT are the principal modalities discussed for evaluating urinary tract pathology in children and adolescents with hematuria, with modality selection determined by the clinical scenario ^[122]A1c. In lower-pole renal stones, the evidence base specifically addresses stones measuring <2 cm treated by ureteroscopy and lasertripsy, comparing treatment in situ with displacement to the upper pole ^[99]A1a. This size and location category is clinically relevant for procedural risk stratification, although the cited systematic review does not establish a universal severity stage or a single preferred approach for every patient ^[99]A1a.

Stone composition and physical characteristics may further refine risk and treatment suitability. In patients with uric-acid-predominant stones, a 2024 nomogram study classified stones as mixed when uric acid constituted 50–90% of composition and as pure when it constituted ≥95%; pure stones had lower mean density than mixed stones (450 vs 600 Hounsfield units) and were less often radiopaque ^[125]B3b. These findings support using composition, radiopacity, and CT density when estimating the likelihood that oral chemolysis may be appropriate, while recognizing that the cited study was retrospective ^[125]B3b.

Procedural infectious risk

Infectious risk is an important severity modifier before percutaneous nephrolithotomy (PCNL). A randomized EDGE Consortium trial enrolled patients at moderate to high risk for sepsis because of a positive preoperative urine culture or an indwelling urinary drainage tube and compared 2 versus 7 days of preoperative antibiotics ^[117]A1b. The study was designed to determine whether extended preoperative therapy reduced postoperative sepsis compared with the shorter regimen; its population should not be extrapolated directly to low-risk patients ^[117]A1b. Additional observational evidence found positive stone cultures in 56% of PCNL patients and multiple organisms in 25%, underscoring the potential difference between urine and stone microbiology when estimating postoperative infectious risk ^[277]. A separate retrospective study of 399 PCNL patients evaluated postprocedural systemic inflammatory response syndrome (SIRS) and developed a nomogram incorporating independent clinical and immunologic predictors, including PD-1^hi^CXCR5− CD4+ peripheral T-helper cells; this remains exploratory evidence ^[278].

Risk of intervention during ureteric colic

Patients initially selected for surveillance after acute ureteric colic do not have uniform outcomes. In a retrospective cohort of 870 eligible patients, Bajaj and colleagues developed and externally validated a nomogram using clinical and stone-related variables to predict subsequent surgical intervention ^[126]B3b. The model is relevant when deciding whether apparently suitable patients can continue observation, but it is a prediction tool rather than a replacement for reassessment of worsening pain, infection, obstruction, or renal dysfunction ^[126]B3b.

Recurrence-risk stratification

Recurrence risk is multifactorial and may be influenced by inherited susceptibility, metabolic disease, anatomy, body composition, and stone phenotype. A systematic review and causal-network analysis identified multiple candidate genes associated with idiopathic urolithiasis, while emphasizing that the genetic architecture remains incompletely defined and that molecularly targeted prevention requires further validation ^[274]. In a prospective 5-year study of 1,001 patients rendered stone-free after surgical removal, 49 single-nucleotide polymorphisms (SNPs) were genotyped and combined with clinical variables to construct a recurrence-prediction nomogram, supporting genetic risk as a possible adjunct rather than an established standalone staging system ^[275].

Specific clinical subgroups may have distinctive trajectories. In primary hyperparathyroidism, a retrospective cohort of 197 patients was used to develop a nomogram incorporating demographic, laboratory, urinalysis, stone, and treatment variables for recurrence prediction ^[281]. In a retrospective cohort of 81 patients with unilateral nephrolithiasis, greater perirenal fat thickness was associated with higher BMI and hyperlipidemia and was associated with poorer recurrence-free survival, although the small sample and observational design limit generalizability ^[280]. Among patients with nephrolithiasis and type 2 diabetes, a Canadian target-trial emulation included 20,146 individuals and compared SGLT-2 inhibitors with GLP-1 receptor agonists or DPP-4 inhibitors for recurrent nephrolithiasis outcomes, including analyses of patients with concomitant gout ^[279].

Inherited and systemic kidney disease may further modify prognosis. A prospective cohort of 410 patients with autosomal dominant polycystic kidney disease used CT-confirmed collecting-system stones, excluding cyst-wall calcifications, to evaluate associations with initiation of renal replacement therapy; the study addresses whether nephrolithiasis is linked to long-term kidney disease progression in this high-risk population ^[191]B2b. In gout, a prospective cohort of 1,497 Chinese patients used clustering based on serum urate, fractional uric-acid excretion, gout duration, and kidney-stone burden to examine progression to CKD stage ≥3, with additional assessment of genetic risk ^[248]. Finally, a retrospective cohort of hospitalized urology patients developed an exploratory admission-based AKI model using KDIGO serum-creatinine criteria, emphasizing that acute kidney injury risk should be assessed dynamically during hospitalization ^[68]B3b.

Practical risk categories

A practical framework is: (1) emergency/high risk—obstruction with sepsis, acute renal failure, or clinical deterioration; (2) procedurally high risk—positive urine culture, indwelling drainage, positive or polymicrobial stone culture, or elevated predicted SIRS risk; (3) intermediate risk—anatomic or stone features such as lower-pole stones <2 cm, uric-acid-predominant composition, or a high predicted likelihood of intervention; and (4) recurrence/renal-progression risk—prior stones, genetic or metabolic predisposition, primary hyperparathyroidism, gout, ADPKD, obesity-related phenotypes, or declining kidney function ^{[99]A1a[121]A1c[125]B3b[126]B3b[191]B2b[248][274][275][277][278][280][281]}. These categories should be revisited as symptoms, cultures, renal function, imaging, and treatment response evolve ^{[121]A1c[126]B3b}.

Immediate assessment and triage

Acute renal colic requires prompt assessment of pain, vomiting, hydration, renal function, urinary infection, obstruction, and alternative diagnoses. The 2026 AUA surgical-management guideline series addresses evaluation, treatment, surgical management, and future directions for kidney and ureteral stones; the supplied abstracts do not reproduce the individual graded statements or drug-level recommendations, so local guideline-concordant protocols should be used for specific analgesic, antibiotic, and procedural choices ^{[10]A1c[11]A1c[9]A1c}.

A prospective emergency-department cohort found that 60 of 602 patients (10%) underwent surgery within 7 days of presentation for renal colic. The CLAD-MB score was prospectively evaluated to predict this outcome and may help identify patients who require expedited urologic follow-up or intervention, although the supplied abstract does not provide the complete score, calibration, or a validated treatment threshold ^[137]B2b.

When urgent decompression is required

The central emergency question is whether an obstructed urinary system is complicated by infection, acute kidney injury, uncontrolled symptoms, or another high-risk feature. Relief of upper urinary tract obstruction is clinically important in patients with acute renal dysfunction: a prospective observational study specifically compared endocannabinoid responses before and after relief of obstruction in patients with and without acute kidney injury, supporting decompression as a biologically relevant event in obstructive renal injury, although it does not establish a biomarker-guided indication or timing strategy ^[232]C.

When infection is suspected in an obstructed system, obtain appropriate cultures, begin institutionally appropriate antimicrobial therapy, and involve urology urgently for drainage. The supplied AUA abstracts establish that evaluation and treatment of kidney and ureteral stones are addressed in the guideline series, but they do not provide the full text of the emergency-decompression statements; therefore, this section should not be interpreted as replacing the complete guideline or local sepsis pathway ^{[10]A1c[11]A1c[9]A1c}.

Temporary drainage is generally achieved by ureteral stenting or percutaneous nephrostomy according to anatomy, clinical stability, expertise, and anticipated definitive treatment. Definitive stone treatment should be planned after stabilization of infection or systemic illness. This staged approach is particularly important because infection-related complications remain a major concern in endourologic surgery: positive stone cultures were reported in 56% of 293 PCNL patients, and 25% had cultures containing multiple organisms in a retrospective cohort ^[277]. A separate study evaluated postoperative sepsis using verified Sepsis-3 criteria rather than diagnosis codes, emphasizing that reported post-ureteroscopy sepsis rates may be affected by outcome-definition and ascertainment methods ^[285]C.

Infection-risk procedural planning

Patients at increased infectious risk require careful preoperative assessment, culture-directed treatment when indicated, and consideration of drainage or staged treatment rather than forcing definitive stone clearance during an unstable episode ^{[9]A1c[10]A1c[11]A1c}. A multicenter single-arm study evaluated flexible navigable suction ureteral access sheath-assisted retrograde intrarenal surgery under local anesthesia in patients with stones ≤30 mm and persistent asymptomatic bacteriuria or pyuria after antibiotic therapy; the study was designed to assess postoperative fever reduction, but its noncomparative design does not establish superiority over standard drainage or surgery ^[282].

Definitive treatment after stabilization

The AUA guideline series covers surgical treatment of renal and ureteral stones and was developed through systematic searches of MEDLINE and EMBASE, with systematic reviews followed by primary-literature review ^{[9]A1c[10]A1c[11]A1c}. Choice among ureteroscopy, shock-wave treatment, and percutaneous nephrolithotomy should therefore be individualized using stone location and burden, obstruction, anatomy, infection status, renal function, prior procedures, and patient preferences; the supplied abstracts do not provide the complete procedure-selection thresholds ^{[9]A1c[10]A1c[11]A1c}.

For renal stones ≤2 cm, a 2026 Bayesian network meta-analysis compared suction-assisted flexible ureteroscopy using flexible aspiration navigable sheaths or direct in-scope suction with conventional access sheaths. It included 17 studies and evaluated 30-day stone-free rate, operative time, fever, sepsis, and complications; results should be interpreted as comparative evidence for definitive stone treatment, not as evidence for emergency decompression ^[329]. Real-world data for a ureteroscope enabling simultaneous laser lithotripsy and suction included 61 cases and 106 stones, but the retrospective single-center design limits generalizability ^[93]C4.

For renal stones 10–30 mm, prospective observational evidence evaluated total tubeless mini-PCNL, while a randomized trial of 120 adults with solitary renal pelvic stones <3 cm examined tract infiltration with 0.25% bupivacaine for postoperative pain; these studies inform selected definitive-procedure and recovery decisions rather than initial emergency drainage ^[286][283]. Opioid-free discharge after PCNL has also been studied prospectively using counseling, multimodal analgesia, and detailed instructions, supporting structured discharge pathways where clinically appropriate ^[287]C. Electronic health-record integration has been evaluated as a way to standardize emergency renal-colic care, pain management, opioid use, and discharge planning, although the supplied abstract does not provide full outcome estimates ^[288].

Follow-up and safety net

Discharge is appropriate only when pain and vomiting are controlled, renal function and infection risk have been assessed, and timely urologic follow-up is arranged. Follow-up access matters: a retrospective cohort specifically examined language-associated differences in time to clinic review, surgery, emergency-department revisits, and completion of metabolic evaluation after acute renal colic ^[284]. Patients should receive explicit return precautions for fever, rigors, worsening or recurrent uncontrolled pain, persistent vomiting, reduced urine output, syncope, or clinical deterioration ^{[10]A1c[11]A1c[9]A1c}.

Management framework

Long-term management has two complementary aims: reducing recurrence through dietary, metabolic, and pharmacological measures, and removing stones when symptoms, obstruction, infection, growth, renal-risk factors, or patient preference justify intervention. The 2026 AUA Medical Management Guideline provides a framework for treatment and follow-up of patients with a history of kidney stones, with the objective of reducing recurrent disease. ^[290] Recurrence after an initial episode occurs in approximately 30–50% within 5 years without dietary and/or pharmacological prevention. ^[333]

Preventive care should be individualized to stone composition, comorbidities, renal function, and 24-hour urine findings. Dietary targets address urine volume and urinary concentrations of calcium, oxalate, uric acid, and citrate. ^[333] A randomized trial compared a generalized, guideline-based empiric strategy with therapy tailored to 24-hour urine results; the available evidence supports the clinical relevance of comparing these approaches, but the supplied abstract does not report the comparative numerical outcomes. ^[333] Weight and metabolic management may be particularly relevant in uric-acid stone formers with obesity, diabetes, and persistently acidic urine; an open-label randomized feasibility study evaluated phentermine/topiramate in adults with urine pH <5.8 and stones containing ≥80% uric acid, but its small feasibility design does not establish this combination as standard stone therapy. ^[334]C

Observation versus definitive treatment

Asymptomatic renal stones may be observed when there is no infection, obstruction, clinically important growth, or unacceptable risk, with surveillance and shared decision-making. ^[14]A1a A 2026 systematic review and meta-analysis of randomized trials directly compared active intervention with observation for asymptomatic stones because some observed stones subsequently cause pain, obstruction, infection, enlargement, or require delayed intervention. ^[14]A1a The choice should therefore incorporate stone size and location, anatomy, renal function, occupational or travel considerations, access to emergency care, patient anxiety, and the anticipated burden of surveillance; the supplied abstract does not provide pooled effect estimates. ^[14]A1a

Intervention is generally favored when a stone is symptomatic, obstructing, infected, enlarging, associated with impaired drainage or threatened renal function, or unlikely to remain safely observable. These indications must be individualized because stone-free rate, morbidity, cost, quality of life, and the likelihood of staged or ancillary procedures differ among extracorporeal shock-wave lithotripsy (SWL), ureteroscopy (URS), and percutaneous nephrolithotomy (PCNL). ^[111]A1a

Selecting an endourologic procedure

PCNL remains the reference approach for large or complex intrarenal stones. ^[332] ECIRS combines antegrade and retrograde access and has been evaluated against PCNL for upper-tract calculi in an updated systematic review and meta-analysis; its potential advantages relate to simultaneous access and enhanced intrarenal visualization, while comparative decisions should account for stone-free rate, complications, and perioperative outcomes. ^[332] For bilateral complex disease, same-session bilateral PCNL has been compared with staged bilateral PCNL in a meta-analysis, and synchronous bilateral PCNL has likewise been compared with staged unilateral procedures; these strategies should be reserved for appropriately selected patients and experienced centers because bilateral treatment concentrates procedural risk. ^{[112]A1a[202]A1a}

For renal stones measuring 2–3 cm, randomized-trial evidence has compared flexible and navigable suction-sheath retrograde intrarenal surgery (FANS-RIRS) with mini-PCNL, specifically assessing stone-free rate, perioperative variables, hemorrhagic complications, and infectious complications. ^[101]A1a For stones >2 cm in a solitary kidney, propensity-matched evidence has compared FANS flexible URS with mini-PCNL using a composite of complications, 1-month stone-free status, and postoperative length of stay; preservation of drainage and renal function is especially important in this setting. ^[270] For stones ≤2 cm, suction-assisted URS—including FANS and direct in-scope suction—has been evaluated against conventional ureteroscopy in a Bayesian network meta-analysis examining 30-day stone-free rate, operative time, fever, sepsis, and complications. ^[329] These newer suction technologies may expand endoscopic options, but comparative evidence should not be interpreted as eliminating the need to match procedure selection to stone burden, anatomy, infection risk, and operator expertise. ^{[101]A1a[270][329]}

For selected renal stones, SWL remains a noninvasive alternative, whereas URS generally offers direct fragmentation and extraction and PCNL provides the most direct treatment for large burdens; the relative value of each modality should include quality of life and cost rather than stone-free rate alone. ^[111]A1a In children younger than 6 years with 1–2 cm renal stones, a prospective randomized trial compared mini-PCNL with SWL, reflecting the need to balance clearance against pediatric procedural morbidity. ^[60]A1b In children with 1–3 cm upper-tract stones, a retrospective matched comparison evaluated vacuum-assisted mini-PCNL versus FANS-RIRS; reported stone-free rates were 97.3% versus 91.3%, respectively, although the nonrandomized design limits causal interpretation. ^[292]

Special anatomy and procedural innovations

Anatomic variation may require individualized access planning. In pelvic kidneys, a multicenter study compared flexible URS, multimodal image-guided PCNL, and laparoscopic pyelolithotomy; flexible URS was most commonly used (51.1%) and multimodal-guided PCNL accounted for 33.3% of primary treatments. ^[252] Ex vivo back-table stone removal during kidney transplantation has also been reviewed as a strategy to expand use of otherwise suitable donor kidneys, with evidence focused on feasibility, safety, stone characteristics, location, and technique. ^[269]

Robotic-assisted combined intrarenal surgery is an emerging approach intended to facilitate percutaneous access and combine mini-PCNL with ureteroscopic lithotripsy; early prospective two-center evidence remains preliminary and should not replace established PCNL expertise. ^[293]C Steerable aspiration systems have been studied for ureteroscopic evacuation, including investigation of whether 3 cm represents an upper practical limit; the available evidence is observational and does not establish a universal size cutoff. ^[273] In selected PCNL patients with solitary pelvic stones <3 cm, randomized evidence has evaluated local bupivacaine infiltration during tubeless PCNL for postoperative pain, supporting analgesia optimization rather than changing the indication for PCNL. ^[283]

Follow-up

After medical or procedural treatment, follow-up should confirm stone clearance or clinically acceptable residual fragments, detect recurrence or growth, reassess renal function and infection risk, and reinforce preventive therapy. ^[290] The intensity and modality of surveillance should reflect residual burden, stone composition, metabolic abnormalities, anatomy, comorbidity, and the selected intervention. ^[290] Treatments for other mineral disorders should not be assumed to be stone-preventive without direct evidence: for example, two-year data on palopegteriparatide address renal-function outcomes in adults with chronic hypoparathyroidism, not definitive nephrolithiasis treatment. ^[328]

From procedural relief to recurrence prevention

Treatment of nephrolithiasis has evolved from primarily removing or bypassing obstructing calculi to integrating acute intervention, metabolic evaluation, dietary modification, pharmacotherapy, and longitudinal surveillance. Contemporary guidance is organized around reducing recurrent disease in patients with a history of kidney stones, using evidence synthesized through an Agency for Healthcare Research and Quality–funded evidence review and the 2026 American Urological Association guideline series. ^[290] This preventive emphasis reflects the substantial untreated recurrence risk: approximately 30–50% of stone formers experience another episode within 5 years of an initial event when dietary or pharmacological prevention is not provided. ^[333]

Increasingly selective metabolic treatment

Earlier preventive strategies commonly applied generalized dietary and medication recommendations, whereas current practice increasingly supports tailoring treatment to stone composition, serum testing, and 24-hour urine findings. ^[290] The principal modifiable urinary targets are low urine volume, excessive urinary calcium, oxalate, or uric acid, and inadequate urinary citrate. ^[333] A 2026 randomized trial directly compared an empiric strategy—standard guideline-based diet and medication therapy—with selective therapy guided by 24-hour urine testing in adults with recurrent stone disease, illustrating the shift from untailored prevention toward individualized treatment. ^[333] The available report identifies the trial design and preventive framework but does not provide sufficient outcome data in the cited abstract to establish superiority of either approach. ^[333]

Patient education has also become part of preventive treatment. A 2026 survey study examined health literacy, counseling intensity, quality of life, and perceptions of primary prevention in people with nephrolithiasis, in the context of American Urological Association metabolic-management guidance. ^[224]C4 These data reinforce that implementation and adherence are clinically important components of prevention, although the cited abstract does not establish a specific counseling intensity or educational intervention as superior. ^[224]C4

Disease-specific medical therapy

Modern treatment increasingly addresses the metabolic cause rather than treating stones as a uniform disorder. In uric acid nephrolithiasis, urinary alkalinization remains an established nonsurgical strategy; a prospective study of staghorn uric acid stones treated with citrate mixtures achieved complete dissolution in 64.7% of 51 patients, while 33.3% required surgery and 2.0% discontinued therapy because of worsening comorbidities without proceeding to surgery. ^[344]C These findings extend oral chemolysis beyond small uncomplicated uric acid calculi, while also showing that large or complex stones may still require operative management. ^[344]C

The relationship between obesity, diabetes, insulin resistance, and acidic urine has prompted exploratory combination therapy. In an open-label randomized feasibility study, obese adults with diabetes, normal renal function, urine pH <5.8, and stones composed of at least 80% uric acid received phentermine/topiramate or pragmatic control treatment for 18 months, with dose escalation and computed-tomography stone-volume assessment. ^[334]C The study was designed to evaluate the feasibility of treating obesity, diabetes, and low urine pH together; the cited abstract does not provide adequate results to establish this combination as standard stone therapy. ^[334]C

Rare and systemic causes have likewise moved toward targeted treatment. Primary hyperoxalurias are inherited disorders of excessive hepatic oxalate production, and delayed diagnosis is a major determinant of prognosis. ^[256] The approval of the first RNA-interfering therapy in 2020 was associated with increased disease awareness and communication from specialist centers, providing an example of treatment evolution from supportive stone management toward mechanism-specific therapy. ^[256] Cystinuria treatment is similarly informed by its genetic basis, principally pathogenic variation in SLC3A1 and SLC7A9, with additional population-specific associations reported for PBX1; circulating microRNAs are being investigated as potential biomarkers of disease severity, but the cited study was exploratory and included only 16 patients. ^[319]C

Correcting endocrine and inherited drivers

When stones arise from primary hyperparathyroidism, treatment has progressively emphasized correction of the underlying disorder rather than repeated stone removal. Parathyroidectomy is the only curative treatment for primary hyperparathyroidism and is therefore regarded as recurrence prophylaxis. ^[92]A1a A 2026 systematic review included 13 studies—two prospective cohorts, ten retrospective cohorts, and one randomized clinical trial—to evaluate recurrence after successful surgery, although the cited abstract does not report a pooled recurrence estimate. ^[92]A1a Normocalcemic primary hyperparathyroidism remains an evolving area: a multicenter retrospective cohort of 527 patients followed the possibility of progression to hypercalcemia, hypercalciuria, kidney stones, bone loss, or fractures over 3 years, reflecting uncertainty about when intervention should occur. ^[300]C

Hypoparathyroidism has also acquired disease-modifying treatment options. Two-year results from the phase 3 PaTHway extension found that 93% (76/82) of participants remained in follow-up at week 104 and that 82% had albumin-adjusted serum calcium within the normal range while receiving daily palopegteriparatide; the study also evaluated sustained renal-function effects. ^[328] This represents a broader shift toward therapies intended to stabilize mineral metabolism and preserve renal function, rather than managing stones or renal complications after they occur. ^[328]

Advances in pediatric and minimally invasive management

Pediatric management has evolved toward minimally invasive, anatomy-preserving procedures selected according to stone size, location, and composition. ^[60]A1b In children younger than 6 years with renal stones measuring <20 mm, a prospective randomized trial compared mini-percutaneous nephrolithotomy with extracorporeal shock-wave lithotripsy, reflecting continued refinement of procedure selection in very young patients. ^[60]A1b Pediatric evaluation is also becoming more metabolic and genetic: a prospective Indian cohort used first-line metabolic testing and, when indicated, stone analysis and whole-exome sequencing in children with nephrolithiasis. ^[262]

The minimally invasive trend extends to complex inflammatory disease associated with obstructing or infected stones. A multicenter pediatric cohort of xanthogranulomatous pyelonephritis reassessed the historically dominant nephrectomy approach in the era of cross-sectional imaging and parenchyma-sparing surgery. ^[343]C This does not replace established stone-directed treatment, but it illustrates the broader evolution from radical procedures toward organ preservation when clinically safe. ^[343]C

Current integrated model and remaining evidence gaps

Current treatment is increasingly risk-based: stone composition, urinary chemistry, comorbidities, inherited disease, and patient adherence inform prevention and intervention. ^[290] Metabolic heterogeneity is documented even within calcium oxalate disease, where retrospective data compared pure and mixed calcium oxalate stones using urine volume, calcium, citrate, oxalate, uric acid, sodium, magnesium, serum calcium, vitamin D, parathyroid hormone, and urine pH. ^[294] Family history may also help identify patients with distinct metabolic abnormalities or stone compositions, although the available evidence is retrospective. ^[127]B3b

Comorbidity-aware follow-up is now essential. Stone disease has been studied in relation to cardiovascular and bone events, ^[247] insulin resistance, ^[297] sarcoidosis-associated calcium disturbances, ^[342] and urinary complications after urinary diversion, including nephrolithiasis after ureterostomy. ^[237] Patients with autosomal dominant polycystic kidney disease have also been evaluated for associations between 24-hour urinary parameters, kidney function, and comorbidities. ^[299] Together, these studies support a modern model in which nephrolithiasis treatment is not limited to episodic clearance: it combines obstruction control, cause-specific therapy, prevention, surveillance, and protection of overall renal and systemic health. ^[290]

Procedure selection and access strategy

Procedure selection should be individualized according to stone burden, location, anatomy, age, renal function, infection risk, and the patient’s tolerance for staged treatment. The principal contemporary modalities remain extracorporeal shock-wave lithotripsy (SWL), ureteroscopy (URS), and percutaneous nephrolithotomy (PCNL); stone-free rate (SFR) should be interpreted alongside invasiveness, cost, and quality of life rather than as the sole endpoint. ^[111]A1a Evidence comparing these modalities is heterogeneous, and patient-centered outcomes may not parallel radiographic clearance. ^[111]A1a

For large or complex renal calculi, PCNL remains the established reference technique. ^[332] Endoscopic combined intrarenal surgery (ECIRS), combining simultaneous antegrade percutaneous and retrograde ureteroscopic access, is an important alternative because it permits complementary visualization and treatment of multiple calyces during one anesthetic. ^[332] The updated systematic review and meta-analysis specifically compared ECIRS with PCNL using SFR, complications, and perioperative variables, but the supplied evidence summary does not provide the pooled numerical estimates; therefore, local expertise and anatomy should guide selection rather than assuming superiority of one approach. ^[332]

Suction-assisted ureteroscopy and miniaturized PCNL

Active fragment evacuation is increasingly incorporated into flexible URS. For renal stones ≤2 cm, a Bayesian network meta-analysis evaluated flexible aspiration navigable sheaths (FANS), direct in-scope suction (DISS), and conventional access sheaths, with 30-day SFR as the primary endpoint and operative time, fever, sepsis, and complications as secondary outcomes. ^[329] Suction-assisted systems are intended to improve clearance and intrarenal pressure control, but the evidence is based on comparative studies synthesized through direct and indirect comparisons and should be interpreted accordingly. ^[329]

For stones 2–3 cm, a prospective controlled cohort compared high-power holmium:YAG laser flexible URS using a vacuum-assisted, flexible, navigable sheath with mini-PCNL. ^[345] In children with 1–3 cm upper-tract stones, a retrospective matched comparison found broadly comparable SFR between vacuum-assisted mini-PCNL and FANS-assisted RIRS, with the reported cohorts using 16-Fr and 10/12-Fr access sheaths, respectively; preoperative stenting was used in a subset of the RIRS group. ^[292] In patients with a solitary kidney and stones >2 cm, propensity-matched retrospective data compared FANS flexible URS with mini-PCNL using a hierarchical endpoint incorporating complications, 1-month SFR, and postoperative length of stay. ^[270] These studies support suction-assisted URS as a potentially useful alternative in selected patients, but their retrospective or nonrandomized designs do not establish equivalence across all stone burdens or anatomies. ^{[270][292][345]}

The upper size boundary for active ureteroscopic evacuation remains unsettled. A single-surgeon observational study evaluated CT-derived stone size and volume to identify thresholds for steerable ureteroscopic renal evacuation using the CVAC aspiration system; stone-free status was defined by Endourological Society CT criteria or a residual fragment <5 mm on ultrasound or radiography. ^[273] Thus, preoperative CT-based volumetric assessment is particularly relevant when considering aspiration-based treatment near the upper limits of ureteroscopic feasibility. ^[273]

Pediatric and special-population considerations

In children younger than 6 years with renal stones <20 mm, a prospective randomized trial directly compared mini-PCNL with SWL, reflecting the need to balance clearance, anesthesia exposure, access morbidity, and the recurrence burden of pediatric stone disease. ^[60]A1b A separate pediatric risk-stratification study reported an overall post-PCNL complication rate of 41%, with most complications being Clavien-Dindo grade I–II and infection-related complications being the most common. ^[346] Supracostal access and preoperative urinary diversion were identified as independent predictors of complications in that cohort, supporting careful access planning and infection optimization before pediatric PCNL. ^[346]

Low-profile single-use flexible ureteroscopes are also being explored in children. Preliminary experience included patients aged 2–16 years, with a median stone size of 9 mm and a range extending to 27 mm, but the small retrospective series cannot define general indications or replace pediatric guideline-based selection. ^[272]C

Bilateral, anomalous, and transplant-related anatomy

For bilateral renal stones, synchronous bilateral PCNL has been compared with staged unilateral PCNL in a meta-analysis of adult patients. The principal outcomes were SFR and Clavien-Dindo complications, and the analysis included studies published from 1996 through 2024. ^[202]A1a Bilateral treatment may reduce the number of anesthetic episodes and admissions, but the decision should account for operative duration, infection risk, renal reserve, and the feasibility of managing complications in both kidneys during one session. ^[202]A1a

Ectopic pelvic kidneys require individualized imaging and access planning because abnormal position and collecting-system orientation complicate conventional percutaneous trajectories. In an 11-center retrospective series, flexible URS was the most common primary treatment, followed by multimodal image-guided PCNL and laparoscopic pyelolithotomy; outcomes were assessed using a strict 0-mm SFR definition and ancillary-procedure and Clavien-Dindo outcomes. ^[252] Multimodal guidance is therefore particularly relevant when selecting a safe tract in anomalous anatomy. ^[252]

Ex vivo stone removal during renal transplantation, including back-table ureteroscopy and other techniques, has been reviewed as a strategy for using selected donor kidneys that contain calculi. ^[269] The evidence addresses feasibility, safety, stone characteristics, location, and removal technique, but remains based on reported clinical experience rather than high-level comparative trials. ^[269]

Perioperative safety, analgesia, and technology

Renal function and infection status should be incorporated into procedural planning. Hospitalized urology patients are at risk for acute kidney injury, and admission-based clinical and laboratory variables have been evaluated as predictors in a retrospective cohort. ^[68]B3b Patients with autosomal dominant polycystic kidney disease and imaging-confirmed nephrolithiasis require particular attention to baseline renal disease and long-term renal outcomes, which have been examined prospectively. ^[191]B2b Urinary diversion is also clinically relevant: long-term experience after radical cystectomy identified nephrolithiasis among late complications associated with urinary diversion, particularly in patients treated with ureterostomy. ^[237]

Tubeless PCNL can reduce postoperative discomfort, and a randomized trial in adults with solitary renal pelvic stones <3 cm found that tract infiltration with 20 mL of 0.25% bupivacaine was evaluated as an adjunct to postoperative analgesia. ^[283] This technique should be viewed as procedure-specific analgesic optimization rather than a substitute for multimodal perioperative pain management. ^[283]

Artificial intelligence and deep-learning systems are being studied for ultrasound-based stone detection, classification, complication prediction, and procedural guidance. ^[2]D5 However, the evidence is heterogeneous, and such tools should currently complement—not replace—expert imaging interpretation and intraoperative judgment. ^[2]D5 Robotic-assisted combined intrarenal surgery with electromagnetic percutaneous guidance has undergone preliminary prospective evaluation, including robotic mini-PCNL with concurrent ureteroscopic lithotripsy and follow-up to 90 days; early evidence remains limited and does not yet establish superiority over conventional access. ^[293]C

Practical synthesis

Use PCNL or ECIRS for appropriately selected large or complex stones, consider suction-assisted URS for carefully selected smaller or anatomically favorable stones, and favor miniaturized systems when reducing tract size is a priority. ^{[270][292][329][332][345]} In children, solitary kidneys, bilateral disease, anomalous kidneys, urinary diversions, and impaired renal function, access planning, infection prevention, renal preservation, and the likelihood of secondary procedures should weigh as heavily as the anticipated SFR. ^{[60]A1b[68]B3b[191]B2b[202]A1a[237][252][346]}

Overview

Nephrolithiasis may cause acute pain, urinary obstruction, infection, renal impairment, and the need for invasive treatment. Recurrent disease may contribute to kidney damage, sepsis, and repeated procedures, although the magnitude of long-term risk varies with stone burden, recurrence, infection, comorbidity, and treatment exposure. ^[136]A1a Asymptomatic stones are not necessarily benign: during surveillance, some patients develop pain, obstruction, infection, stone growth, or require intervention. ^[14]A1a

Acute obstruction and infection

Ureteral or renal pelvic obstruction can produce renal colic and may compromise renal function, particularly when obstruction is bilateral, occurs in a solitary kidney, or is accompanied by infection. The supplied evidence identifies obstruction and infection as clinically important outcomes of untreated or observed asymptomatic stones, but does not provide a pooled estimate for the frequency of each complication. ^[14]A1a Infection-related complications are especially concerning because recurrent nephrolithiasis has been associated with sepsis in the evidence base reviewed for prevention. ^[136]A1a

An obstructed, infected urinary tract is a time-critical urological emergency requiring urgent drainage and antimicrobial management; however, the supplied references do not quantify comparative drainage outcomes or specify an antibiotic regimen. Antimicrobial selection should account for local resistance and patient-specific risk. In a contemporary cohort of acute pyelonephritis, multidrug-resistant pathogens were specifically evaluated alongside renal impairment or renal-failure status at presentation, underscoring the importance of integrating kidney function and healthcare-exposure history into infection-risk assessment. ^[304]C

Renal functional consequences

Repeated obstruction, infection, and recurrent stone formation may lead to renal damage. The prevention systematic review explicitly frames recurrent stones as a potential cause of kidney damage, sepsis, and invasive procedures. ^[136]A1a Patients with recurrent disease therefore require risk assessment and preventive management rather than treatment of individual episodes alone. The 2026 American Urological Association guideline is intended to reduce recurrent disease through medical management and follow-up of patients with a history of kidney stones. ^[290]

Long-term renal outcomes are also relevant in selected living kidney donors with incidental stones. In a 10-year single-center retrospective study, donors with asymptomatic nephrolithiasis identified before donation were compared with stone-free donors for post-donation recurrence and estimated glomerular filtration rate; the abstract indicates that these outcomes were specifically assessed but does not provide the numerical results. ^[305] Consequently, donor selection and counseling should not be generalized to patients with symptomatic, recurrent, obstructing, or metabolically high-risk stones. ^[305]

Recurrence and metabolic complications

Stone recurrence is common without preventive therapy: the URINE trial background states that 30–50% of stone formers may recur within 5 years after an initial episode when dietary and/or pharmacological prevention is not used. ^[333] Preventive strategies target urine volume and urinary calcium, oxalate, uric acid, and citrate concentrations. ^[333] A randomized trial comparing empiric treatment with treatment guided by 24-hour urine testing evaluated indapamide, potassium citrate, dietary counseling, and, when indicated, allopurinol; the supplied abstract does not report the final comparative outcomes. ^[303] Another randomized trial similarly compared empiric and selective prevention strategies, with urinary supersaturation of calcium oxalate and calcium phosphate as outcomes. ^[333]

Primary hyperparathyroidism is a potentially correctable metabolic contributor to calcium nephrolithiasis. A systematic review evaluated whether parathyroidectomy reduces subsequent stone recurrence in adults with surgically treated primary hyperparathyroidism and documented nephrolithiasis; the available abstract does not provide the pooled recurrence estimate. ^[92]A1a Family history may also signal an increased likelihood of metabolic abnormalities or particular stone compositions, although the supplied abstract does not provide the study’s numerical associations. ^[127]B3b

Procedure-related complications

Treatment can introduce bleeding, infection, ureteral or renal injury, residual fragments, and the need for ancillary procedures, but the magnitude of these risks depends on procedure type, stone burden, anatomy, and patient characteristics. For large intrarenal stones, percutaneous nephrolithotomy remains the reference treatment, while endoscopic combined intrarenal surgery provides simultaneous antegrade and retrograde access; a 2026 systematic review compared these approaches for stone-free rates, complications, and perioperative outcomes. ^[332]

For bilateral complex stones, same-session bilateral percutaneous nephrolithotomy has been compared with staged bilateral treatment in meta-analyses assessing efficacy, safety, efficiency, and Clavien–Dindo complications. ^[112]A1a A separate meta-analysis compared synchronous bilateral with staged unilateral percutaneous nephrolithotomy using stone-free rate and complication rate as primary outcomes. ^[202]A1a These studies support individualized selection rather than assuming that a single-session approach is universally safer; the supplied abstracts do not provide the pooled effect estimates.

For renal stones ≤2 cm, suction-assisted flexible ureteroscopy has been studied as a strategy intended to improve clearance and reduce complications. Comparative outcomes included 30-day stone-free rate, operative time, fever, sepsis, and overall complications. ^[329] In children younger than 6 years with renal stones <20 mm, a randomized trial compared mini-percutaneous nephrolithotomy with shock-wave lithotripsy, reflecting the need to balance stone clearance against procedure-related morbidity in a population with high recurrence and substantial potential morbidity. ^[60]A1b

Special anatomic and clinical settings

Anatomic abnormalities can increase procedural complexity and may affect the risk of residual stones or additional interventions. In a multicenter study of congenital pelvic kidneys, flexible ureteroscopy, multimodal image-guided percutaneous nephrolithotomy, and laparoscopic pyelolithotomy were assessed for stone-free rate, ancillary procedures, and Clavien–Dindo complications. ^[252] Pediatric flexible ureterorenoscopy has also been evaluated in small observational experience, but the limited sample and preliminary design prevent reliable estimation of complication rates. ^[272]C

Transplant recipients and urinary-diversion patients require additional vigilance. A systematic review evaluated ex vivo stone removal during renal transplantation for safety and feasibility, while a large stone-composition study specifically characterized urinary stones in transplant recipients. ^[269] After radical cystectomy, urinary-diversion type was associated with differing late complication profiles; ureterostomy patients showed a greater propensity for late urinary tract infection and nephrolithiasis in the reported cohort. ^[237]

Prevention and follow-up

Because recurrence and its complications are preventable in some patients, follow-up should include individualized dietary, pharmacological, metabolic, and imaging planning. The AUA guideline addresses treatment and follow-up, while a systematic review found that available prevention studies did not evaluate imaging strategies. ^{[290] [136]A1a} Observation of asymptomatic stones should therefore involve shared decision-making and surveillance tailored to stone size, location, growth, symptoms, obstruction risk, infection risk, renal function, and patient preference. ^[14]A1a

Overall course

Nephrolithiasis is a recurrent disorder, and recurrence after an initial episode occurs within 5 years in approximately 30–50% of untreated stone formers, although the cited estimate derives from background data in a randomized dietary-prevention trial and may not apply equally to all stone phenotypes. ^[333] Recurrence risk reflects persistent abnormalities in urine volume and the urinary concentration of calcium, oxalate, uric acid, and citrate; preventive strategies therefore aim to increase urine volume or modify these risk factors. ^[333]

The long-term prognosis is heterogeneous. Recurrent disease may result in further symptomatic episodes, obstruction, infection, emergency care, invasive procedures, or kidney damage, although the magnitude of risk depends on stone burden, composition, anatomy, comorbidity, and treatment. ^[136]A1a Cystinuria is a particularly recurrent inherited disorder caused primarily by impaired proximal tubular cystine reabsorption associated with SLC3A1 or SLC7A9 variants; its clinical course is heterogeneous and remains difficult to predict. ^[319]C

Asymptomatic and residual stones

With more frequent and sensitive imaging, asymptomatic stones are increasingly detected. ^[14]A1a Many remain stable during observation, but some enlarge or subsequently cause pain, obstruction, infection, or a need for intervention. ^[14]A1a Current management commonly favors surveillance for selected asymptomatic stones, with individualized shared decision-making that considers stone characteristics, patient preferences, access to follow-up, and the consequences of a future obstructing event. ^[14]A1a

A 2026 systematic review and meta-analysis specifically compared active stone-directed intervention with observation in randomized trials of asymptomatic kidney stones; the supplied abstract establishes this comparison and the rationale for surveillance but does not provide the pooled outcome estimates. ^[14]A1a Similarly, the 2026 AUA guideline is intended to provide a framework for treatment and follow-up to reduce recurrent disease, but the supplied abstract does not include its specific follow-up intervals or graded recommendations. ^[290]

Kidney function and chronic kidney disease

Stone disease can be associated with clinically important renal outcomes, particularly when obstruction, infection, recurrent procedures, or an underlying systemic disorder is present. ^[136]A1a Evidence is not uniform across populations. In a prospective cohort of 410 patients with autosomal dominant polycystic kidney disease, imaging-confirmed nephrolithiasis was evaluated in relation to initiation of renal replacement therapy; the study was designed to clarify whether stones accelerate progression, but the supplied abstract does not report the hazard estimate or final association. ^[191]B2b

Gout patients also have heterogeneous renal trajectories. In a prospective Chinese cohort of 1,497 patients with gout, clustering incorporated serum urate, fractional uric-acid excretion, gout duration, and kidney-stone burden, with progression to CKD stage ≥3 as the primary renal outcome; the supplied abstract does not report the cluster-specific risk estimates. ^[248]

Primary hyperparathyroidism is a potentially reversible cause of calcium stones. A systematic review of 13 studies evaluated stone recurrence after successful parathyroidectomy in adults with documented nephrolithiasis and at least 12 months of follow-up; it examined recurrence and predictors, but the supplied abstract does not provide the pooled recurrence rate. ^[92]A1a

Prevention and surveillance

A systematic review of 31 prevention studies—26 randomized trials and 5 nonrandomized intervention studies—evaluated dietary, pharmacologic, and surveillance approaches in adults and children; all but three studies enrolled adults, and none evaluated imaging strategies. ^[136]A1a The evidence base therefore supports prevention research but does not establish an evidence-based imaging schedule from these studies. ^[136]A1a

The URINE randomized trial compared empiric treatment with selective treatment guided by 24-hour urine testing in adults with recurrent idiopathic calcium stones. ^[303] Both groups underwent testing at baseline, 4 weeks, and 8 weeks; empiric treatment included dietary and fluid counseling plus indapamide and potassium citrate, whereas selective treatment used 24-hour urine results to choose among diet, indapamide, potassium citrate, and/or allopurinol. ^[303] The supplied abstract does not report the comparative urinary supersaturation results or clinical recurrence outcomes. ^[303]

A related randomized trial likewise compared empiric guideline-based diet and medication therapy with therapy tailored to 24-hour urine testing in adults with recurrent stones. ^[333] A large propensity-matched database study compared empirically initiated potassium citrate with thiazide therapy and excluded patients with documented abnormalities favoring targeted treatment, prior stone surgery, or previous exposure to either drug; its supplied abstract does not provide the comparative surgery outcome. ^[330]

Special populations and procedural prognosis

In carefully selected living kidney donors with asymptomatic nephrolithiasis, a 10-year single-center retrospective study compared postdonation stone recurrence and estimated glomerular filtration-rate trajectories with those of stone-free donors; the supplied abstract does not report the comparative results. ^[305] Back-table stone removal during kidney transplantation is being used to expand the donor pool, but the evidence consists of literature describing feasibility, safety, stone characteristics, and techniques rather than definitive long-term recurrence data. ^[269]

Procedural success should not be equated with long-term cure. A systematic review comparing extracorporeal shock-wave lithotripsy, ureteroscopy, and percutaneous nephrolithotomy assessed stone-free rate, cost, and quality of life, reflecting the need to evaluate patient-centered outcomes in addition to radiographic clearance. ^[111]A1a In children with 1–3 cm stones, a retrospective comparison of vacuum-assisted mini-PCNL and suction-assisted flexible ureteroscopy reported high short-term stone-free rates, but these results do not define lifetime recurrence risk. ^[292] Similar short-term comparative evidence exists for suction-assisted flexible ureteroscopy versus mini-PCNL in solitary-kidney patients with stones larger than 2 cm. ^[270] Preliminary pediatric single-use flexible ureterorenoscopy data involved only 11 patients and 15 procedures, limiting prognostic inference. ^[272]C

Lifestyle and etiology may modify future risk. Wearable-based activity data were used in a retrospective cohort to examine incident-stone risk in individuals without prior stone disease, but the supplied abstract does not report the hazard estimates. ^[250] Family history was studied in 101 stone-clinic patients for associations with metabolic abnormalities and stone composition, but the evidence is observational and does not establish an individual recurrence probability. ^[127]B3b A large Chinese stone-composition analysis included 33,616 samples and compared renal-transplant recipients with non-transplant controls; its findings may inform etiology and prevention in transplant populations but do not directly define natural history. ^[236] Ketogenic-diet evidence in infants concerns epilepsy treatment rather than nephrolithiasis prognosis and should not be extrapolated to stone prevention. ^[257]

Children and adolescents

Pediatric nephrolithiasis warrants evaluation for recurrent, metabolic, medication-related, and hereditary causes because childhood stones may be associated with substantial recurrence, morbidity, nephrocalcinosis, chronic kidney disease (CKD), and, in severe disease, kidney failure ^{[60]A1b[249][307]C}. Assessment should therefore include stone analysis when available, serum and urine metabolic testing, review of dietary and medication exposures, and consideration of genetic disease when presentation is early, recurrent, bilateral, or associated with nephrocalcinosis or impaired kidney function ^{[234]C[235]C[256][307]C}.

For children younger than 6 years with renal stones measuring 1–2 cm, a prospective randomized trial was designed to compare mini-percutaneous nephrolithotomy (mini-PCNL) with extracorporeal shock-wave lithotripsy (SWL), reflecting the importance of stone size, location, and composition in selecting treatment ^[60]A1b. The supplied abstract does not report the trial’s comparative results; therefore, treatment selection should remain individualized according to anatomy, stone burden, obstruction, infection, renal function, and local pediatric expertise ^[60]A1b. In children with 1–3 cm upper-tract stones, a retrospective comparative study evaluated vacuum-assisted mini-PCNL using a 16-Fr sheath versus flexible ureteroscopy with a flexible, navigable suction access sheath using 10/12-Fr equipment; preoperative stenting was used in 34.78% of the ureteroscopy group, and reported stone-free rates were 97.3% and 91.3%, respectively ^[292].

Pediatric PCNL is effective but requires careful complication-risk assessment. In a 10-year single-center analysis of 100 children, the overall postoperative complication rate was 41%, most complications were Clavien-Dindo grade I–II, and infection-related complications were the most common category at 20% ^[346]. Supracostal access and preoperative urinary diversion with a nephrostomy tube or double-J stent were independently associated with higher complication risk, with odds ratios of 2.82 and 4.87, respectively ^[346]. Long-term management is particularly important in cystinuria: a 25-year pediatric experience evaluated PCNL, recurrence, complications, and renal outcomes, emphasizing that sustained adherence to medical therapy substantially influences long-term results ^[309]C.

Pediatric medication- and diet-associated stones

Ceftriaxone can cause urinary tract calcification or urolithiasis in children, distinct from its better-known biliary pseudolithiasis; a 2026 systematic review and meta-analysis specifically sought to estimate the pooled frequency of ceftriaxone-induced urolithiasis ^[64]A1a. Because the supplied abstract does not provide the pooled estimate, clinicians should maintain awareness of this potential adverse effect when urinary symptoms, hematuria, obstruction, or new calcifications develop during treatment ^[64]A1a.

Ketogenic and modified Atkins diets used for drug-resistant epilepsy are also relevant stone-risk exposures. A retrospective cohort of 112 children initiating ketogenic or modified Atkins dietary therapy, with 80 having adequate follow-up and complete clinical, laboratory, and outcome data, evaluated nephrolithiasis incidence, associated factors, management, and outcomes ^[255]C. Dietary therapy should therefore be accompanied by renal-risk surveillance and attention to hydration and metabolic abnormalities, particularly when symptoms or urinary abnormalities occur ^[255]C.

Inherited and metabolic disorders

Primary hyperoxaluria may present in infancy or childhood with nephrolithiasis, nephrocalcinosis, progressive CKD, and kidney failure. In a Turkish national registry of 88 children, the median age at diagnosis for primary hyperoxaluria type 1 was 2.6 years, the approximate diagnostic delay was 2 years, and 49.4% had kidney failure at diagnosis ^[307]C. A Tunisian genetically confirmed cohort addressed clinical spectrum, molecular findings, and minimum observed prevalence of primary hyperoxaluria in a population with potentially increased recessive disease burden ^[234]C. Earlier recognition is clinically important because diagnosis delay is a major determinant of prognosis, and a French study reported substantially shorter delays in children than adults in an earlier cohort while evaluating whether awareness improved diagnosis after RNA-interference therapy became available ^[256].

Distal renal tubular acidosis is characterized by metabolic acidosis, growth failure, nephrocalcinosis, nephrolithiasis, and CKD. The European prospective registry collected growth, creatinine, serum and urine biochemistry, genetic, treatment, and clinical data from 2019 through 2024 to assess outcomes under metabolic management ^[249]. Dent disease should be considered in boys with low-molecular-weight proteinuria, hypercalciuria, nephrocalcinosis, stones, or progressive renal impairment; a Korean multicenter series included 48 genetically confirmed male patients with pathogenic variants in CLCN5 or OCRL1 ^[235]C. SLC34A1-related disorders can include infantile hypercalcemia, nephrolithiasis, osteoporosis-hypophosphatemia, and Fanconi renotubular syndrome; a pediatric case series of 11 patients evaluated genotype–phenotype relationships and oral phosphate treatment responses ^[34]C4.

Primary hyperparathyroidism may emerge during adolescence in multiple endocrine neoplasia type 1. In a single-center cohort of 21 genetically confirmed patients diagnosed by age 21 years, primary hyperparathyroidism developed in 71%, with a median age of 18 years, supporting surveillance for hypercalcemia and stone disease in affected young people ^[347]. Chronic hypoparathyroidism has the opposite calcium-handling pattern, with impaired renal calcium reabsorption, persistent hypercalciuria, nephrolithiasis, nephrocalcinosis, and CKD risk; a 2026 systematic review and exploratory meta-analysis evaluated thiazide therapy in adults for reducing urinary calcium and assessing renal safety ^[212]A1a.

Other high-risk populations

In gout, kidney-stone burden is clinically relevant to CKD progression. A prospective cohort of 1,497 Chinese patients used clustering by serum urate, fractional uric-acid excretion, gout duration, and stone burden to examine trajectories to CKD stage ≥3 and explored whether genetic risk improved prediction ^[248]. In autosomal dominant polycystic kidney disease, a retrospective study of 42 adults examined 24-hour urinary parameters in relation to eGFR and comorbidities, providing disease-specific context for metabolic stone assessment ^[299]. Selected living kidney donors with asymptomatic nephrolithiasis were studied retrospectively over 10 years for post-donation recurrence and eGFR trajectories, underscoring the need for careful predonation evaluation and long-term follow-up ^[305].

Pregnancy

No pregnancy-specific cohort, treatment trial, imaging study, or pregnancy outcome data are provided in the supplied references. Consequently, these references cannot establish pregnancy-specific imaging, medication, dietary, or procedural recommendations; management during pregnancy should be individualized using pregnancy-specific guidance and multidisciplinary obstetric–urologic assessment ^{[60]A1b[212]A1a[255]C[292]}.

Prevention strategy

Prevention should be individualized according to stone history, stone composition when available, comorbidities, urinary risk factors, kidney function, age, and patient preferences. The 2026 American Urological Association guideline provides a framework for treatment and follow-up intended to reduce recurrent disease, while emphasizing that prevention and follow-up are components of longitudinal care rather than one-time interventions. ^[290] A systematic review of 31 intervention studies found that evidence was derived predominantly from adults; only three studies included children, and no included study evaluated imaging strategies for preventing recurrence. ^[136]A1a

Dietary and lifestyle counseling is central to prevention. Modifiable targets include increasing urine volume and reducing urinary concentrations of calcium, oxalate, and uric acid while addressing low urinary citrate. ^[333] Observational and randomized evidence has evaluated dietary and lifestyle factors for primary prevention, although the strength and consistency of associations vary across interventions and outcomes. ^[310] Dietary counseling may be delivered empirically or tailored to 24-hour urine findings; a randomized trial compared these approaches in adults with recurrent stone disease after completion of 24-hour urine testing, with empiric therapy based on standard guideline-oriented diet and medication treatment and selective therapy guided by urine results. ^[333]

Pharmacologic prevention should be matched to the suspected metabolic abnormality and balanced against adverse effects. Thiazide and thiazide-like diuretics remain a major preventive option for recurrent calcium stones, particularly when hypercalciuria is present, but recent evidence continues to examine the optimal agent and dose. ^[221]A1a A 2025 network meta-analysis specifically compared different thiazide and thiazide-like regimens for clinical or radiological recurrence and assessed adverse effects, reflecting ongoing uncertainty about comparative efficacy and dosing. ^[195]A1a Umbrella-review evidence supports considering non-surgical medical interventions for prevention, but also emphasizes that certainty differs among therapies and patient populations. ^[220]A1a

Metabolic and secondary-cause evaluation

Patients with recurrent, unusual, severe, or early-onset stones should be assessed for secondary causes when clinically indicated. Primary hyperparathyroidism is an important cause of nephrolithiasis; parathyroidectomy is an established treatment for symptomatic disease, whereas its benefit in mild asymptomatic primary hyperparathyroidism has been evaluated in randomized studies across skeletal, renal, and quality-of-life outcomes. ^[223]A1a Contemporary guidance for sporadic primary hyperparathyroidism addresses adult management using evidence-based clinical-practice methods. ^[311]

Parathyroidectomy may reduce stone recurrence and may slow renal-function decline in primary hyperparathyroidism, but it is not a complete guarantee against future stones. A retrospective cohort study of 1,252 patients with primary hyperparathyroidism and prior nephrolithiasis described beneficial post-operative effects while concluding that surgery was not a panacea. ^[314]C Another retrospective study evaluated longitudinal kidney-function outcomes after parathyroidectomy and reported benefit in renal-function decline measures. ^[315] These observational findings should not be interpreted as proof that surgery eliminates the need for ongoing stone prevention or renal surveillance. ^[314]C[315]

Rare inherited and endocrine disorders should be considered in children, adolescents, patients with multiple affected relatives, recurrent stones with atypical biochemical findings, or nephrolithiasis accompanied by bone or phosphate abnormalities. SLC34A1-related disorders can include nephrolithiasis, hypercalcemia, hypophosphatemia, osteoporosis, and renal tubular dysfunction; oral phosphate therapy and genotype–phenotype relationships have been examined in a small pediatric case series. ^[34]C4 Young patients with multiple endocrine neoplasia type 1 may develop primary hyperparathyroidism early, supporting disease-specific endocrine surveillance when MEN1 is confirmed or strongly suspected. ^[347]

Surveillance of asymptomatic or residual stones

Observation is reasonable for many asymptomatic renal stones when there is no infection, obstruction, progressive renal impairment, unacceptable occupational risk, or other compelling indication for treatment. The decision should be individualized through shared decision-making because asymptomatic stones may remain stable but can subsequently cause pain, obstruction, infection, growth, or intervention. ^[14]A1a Evidence on natural history is based largely on observational studies of small, asymptomatic or residual stones; systematic reviews have specifically evaluated stones ≤10 mm over long-term follow-up. ^[77]B2a A 2025 review likewise synthesized incidentally recognized clinically silent stones in otherwise healthy adults, reflecting persistent uncertainty regarding which patients benefit from early intervention. ^[313]

Active stone-directed treatment should not automatically replace surveillance for an asymptomatic stone. A systematic review and meta-analysis of randomized trials compared intervention with observation and was designed to quantify differences in stone-related events and procedural outcomes; its clinical implication is that management should be individualized rather than universally interventionist. ^[14]A1a Imaging follow-up should therefore be selected according to stone burden, location, symptoms, risk of obstruction, renal function, and the consequences of missed progression; importantly, the 2026 prevention review found no eligible studies directly comparing imaging strategies for recurrence prevention. ^[136]A1a

Special populations

Renal-transplant recipients require individualized surveillance because de novo nephrolithiasis occurs in the setting of a single functioning kidney, altered urinary anatomy, immunosuppression, and substantial comorbidity. A systematic review evaluated prevalence, presentation, stone characteristics, and outcomes of extracorporeal shock-wave lithotripsy, medical therapy, percutaneous nephrolithotomy, open surgery, and ureteroscopy in this population. ^[222]A1a Patients with spinal cord injury may also have distinctive stone risks and treatment burdens; a multicenter registry study examined associations between prior stone surgery, complications, and quality of life. ^[69]B2b

Practical follow-up principles

Follow-up should confirm adherence, reassess symptoms and renal function, review stone composition when available, and repeat metabolic testing when results are likely to change management. The evidence base supports targeted prevention and shared decision-making, but does not establish a single universally superior surveillance-imaging schedule. ^{[136]A1a[290][333]} Patients should seek urgent assessment for fever or suspected infection with obstruction, anuria, uncontrolled pain or vomiting, or evidence of acute kidney injury, because these findings may require prompt decompression or intervention; the asymptomatic-stone literature specifically identifies obstruction, infection, and symptomatic progression as clinically important events. ^{[14]A1a[77]B2a[313]}