Adrenal Crisis

Adrenal crisis is the most severe, life-threatening manifestation of adrenal insufficiency (AI), defined by acute deterioration with hypotension or shock requiring parenteral glucocorticoid administration and hospitalization ^[6]D5[7]D5. The condition is also termed acute adrenal insufficiency or Addisonian crisis. Synonyms include:

• Adrenal crisis (AC)
• Acute adrenal insufficiency
• Addisonian crisis
• Adrenal emergency

A universally accepted definition remains lacking, and the term is often operationalized in research as an acute illness necessitating intravenous or intramuscular glucocorticoids with clinical features of hypovolemia, hypotension, or altered consciousness ^[6]D5[7]D5. In pediatric congenital adrenal hyperplasia (CAH) studies, a sick day episode (SDE) is distinguished from AC: SDE refers to an illness requiring increased glucocorticoid dosing but not meeting crisis criteria, whereas AC denotes the need for parenteral therapy and hospitalization ^[1]B2b.

Classification of Adrenal Insufficiency

AI is classified by the anatomic level of the hypothalamic-pituitary-adrenal (HPA) axis disruption. This nomenclature is essential for understanding the etiology and risk of crisis.

Primary AI carries the highest risk of adrenal crisis due to concomitant mineralocorticoid deficiency and inability to mount a counterregulatory response ^[6]D5. Secondary and tertiary AI, while less prone to mineralocorticoid crises, still pose significant risk during intercurrent illness or stress ^[3]D5[4]B2a.

Clinical Significance

Adrenal crisis remains one of the leading causes of mortality in patients with AI despite current hormone replacement strategies ^[6]D5. Reported incidence rates vary: 5-10 per 100 patient-years in adults with AI ^[7]D5, 6.9 per 100 patient-years in a cohort after unilateral adrenalectomy for primary aldosteronism ^[2]B2b, and approximately 9 per 100 patient-years in patients treated for Cushing’s syndrome ^[3]D5. In children with CAH, rates are lower (median 0 per patient-year per center) but highly variable ^[1]B2b.

Pearl: Adrenal crisis is defined by the need for parenteral glucocorticoids and hospitalization, not merely by a low cortisol level. The clinical decision to treat must precede confirmatory lab results in any patient with AI presenting with hypotension or shock ^[6]D5[7]D5.

From the classification of adrenal insufficiency, the critical link between a broken hypothalamic-pituitary-adrenal (HPA) axis and the life-threatening decompensation of adrenal crisis becomes clear. This section traces the normal feedback loop, the precise node at which it fails, and the laboratory fingerprint that identifies the lesion.

Normal HPA Axis Physiology

Corticotropin-releasing hormone (CRH) from the hypothalamus stimulates the pituitary to secrete adrenocorticotropic hormone (ACTH), which in turn drives cortisol synthesis and release from the adrenal cortex. Cortisol exerts negative feedback at both the hypothalamus and pituitary, maintaining tight homeostatic control. In primary adrenal insufficiency, the adrenal gland itself is destroyed, removing the end-organ effector; cortisol falls, negative feedback is lost, and ACTH rises unchecked. In secondary (or tertiary) insufficiency, the defect lies upstream, pituitary ACTH deficiency or hypothalamic CRH deficiency, so cortisol is low without an appropriately elevated ACTH ^[12]A1c.

Pathophysiology of Adrenal Crisis

Cortisol is essential for maintaining vascular tone, gluconeogenesis, and modulating the inflammatory response. During stress, infection, surgery, trauma, the normal HPA axis increases cortisol production several-fold. When the axis is compromised, this stress response fails, triggering a cascade that culminates in adrenal crisis.

Step 1: Loss of cortisol surge. Absent the stress-driven rise in cortisol, systemic vascular resistance drops, leading to hypotension and shock that is characteristically refractory to volume resuscitation alone ^[13]D5.

Step 2: Unopposed cytokine release. Cortisol normally suppresses pro-inflammatory cytokines (e.g., tumor necrosis factor alpha). Without it, cytokine release is enhanced, further impairing glucocorticoid receptor function and worsening glucocorticoid deficiency ^[13]D5.

Step 3: Mineralocorticoid deficiency (primary AI only). Destruction of the adrenal cortex also eliminates aldosterone, causing renal sodium wasting, potassium retention, and volume depletion. This amplifies the hypotension and produces hyponatremia and hyperkalemia ^[18]C4.

Step 4: Metabolic decompensation. Cortisol deficiency impairs gluconeogenesis, leading to hypoglycemia, which can cause seizures, coma, and neurologic injury, especially in children ^[19]C4.

Step 5: Clinical phenotype. The combined effects produce the classic triad, hypotension, hypoglycemia, and hyponatremia, with nausea, vomiting, fever, and altered mental status ^[13]D5.

Biochemical Signature

The laboratory pattern that distinguishes primary from secondary AI is the paired hormone measurement:

• Primary AI: Low cortisol with inappropriately elevated ACTH (often >100 pg/mL). Hyperkalemia and hyponatremia are common due to aldosterone deficiency; hyperpigmentation from excess ACTH may be present.
• Secondary AI: Low cortisol with low or inappropriately normal ACTH. Hyponatremia can occur from cortisol-deficiency-driven inappropriate antidiuretic hormone secretion, mimicking SIADH ^[18]C4. Hyperkalemia is absent.

In an acute crisis, obtaining a stat cortisol and ACTH before administering hydrocortisone is ideal, but treatment should never be delayed for results. The diagnosis is confirmed when a random cortisol is <3 µg/dL in a stressed patient, or <18 µg/dL after cosyntropin stimulation, with a flat ACTH response in secondary disease ^[13]D5.

Susceptibility Modifiers

Genetic variants in the glucocorticoid receptor (NR3C1), mineralocorticoid receptor (NR3C2), and 11β-hydroxysteroid dehydrogenase isoforms (HSD11B1, HSD11B2) may alter individual sensitivity to glucocorticoids and predispose to crisis, though the clinical impact remains under investigation ^[9]B3b. In patients with prolonged critical illness, central suppression of ACTH from sustained negative feedback, opioid use, and bile acid accumulation can lead to acquired central adrenal insufficiency, termed critical illness-related corticosteroid insufficiency (CIRCI), which further impairs cortisol production and delays recovery ^[10]D5.

Pearl: In any hypotensive patient with unexplained hypoglycemia or hyponatremia, consider adrenal crisis and administer parenteral hydrocortisone 100 mg bolus immediately; do not wait for confirmatory labs ^[13]D5.

The preceding section detailed the pathophysiology of cortisol deficiency; here we quantify the burden of adrenal crisis and identify those at greatest risk. Adrenal crisis (AC) occurs at a rate of 5-10 crises per 100 patient-years in chronic adrenal insufficiency (AI) ^{[13]D5[23]B2b[32]B2c}. Prospective studies report 8.3 crises per 100 patient-years in mixed primary and secondary AI ^[23]B2b and 4.27 per 100 patient-years in pediatric-onset AI ^[22]B2b. In congenital adrenal hyperplasia (CAH), rates are 8.4 per 100 patient-years in adults and 5.1 per 100 patient-years in children ^[27]B2b; modified-release hydrocortisone reduced this to 3.9 per 100 patient-years ^[21]C4. AC-associated mortality is 0.5 per 100 patient-years, and approximately 6% of crises are fatal ^{[13]D5[23]B2b}; AC contributes to 10% of all deaths in AI patients ^[29]B2b.

Demographic and Temporal Trends

AC-related hospitalizations have increased over the past decade, especially in patients >80 years and those with central AI, likely driven by expanding glucocorticoid and immunotherapy use ^[26]B2b. Adults >60 years have the highest age-specific incidence, which doubles between ages 60-69 and ≥80 ^[33]D5. In the Swiss nationwide cohort (2012-2022), 2302 AC hospitalizations were identified; incidence peaked in the oldest old and was steepest in central AI ^[26]B2b. In children, younger age at enrollment independently predicted AC (relative risk 0.93 per year; 95%) ^[22]B2b.

Risk Factors

Infections are the dominant precipitant, gastrointestinal infection and fever trigger 45-67% of crises ^{[23]B2b[32]B2c}. Other common triggers include emotional stress, major pain, surgery, strenuous physical activity, and heat ^[23]B2b. Prior AC powerfully predicts future events (odds ratio 2.85; 95% CI 1.5-5.5) ^[23]B2b. Additional risk factors vary by etiology:

• Unspecified etiology, advanced age, male sex, sepsis, and cancer predict adverse outcomes in hospitalised patients ^[26]B2b

Special Considerations

The COVID-19 pandemic did not increase AC incidence in children with AI (12.9% prevalence vs 37.4% in the general pediatric population) ^[30]B2b. Only 3.4% of infected children developed AC, all during severe/critical disease ^[30]B2b. In adults, adequately treated AI patients showed no excess COVID-19 severity or AC compared to controls ^[24]B3b. Vaccination against SARS-CoV-2 shortened infection duration (10.1 vs 16.0 days) and prevented severe disease ^[30]B2b.

The clinical presentation of AC, the next section, translates these epidemiological risks into actionable bedside recognition.

Pearl: Incidence is rising, driven by central adrenal insufficiency from glucocorticoid/immunotherapy use, and peaks in patients >80 years.

From the preceding epidemiology , where infection and stress are the commonest precipitants, the transition to clinical recognition is a race against time. The patient before you may not yet have a diagnosis of adrenal insufficiency: in reported cohorts, symptoms had been present for a mean of 5.6 months before diagnosis ^[36]B2b. Yet the presentation of an established crisis is distinctive enough to prompt immediate action.

Presenting Symptoms

The chronic phase of adrenal insufficiency (<sc>primary</sc> or <sc>secondary</sc>) is dominated by fatigue, unintentional weight loss , anorexia, and postural hypotension ^[42]D5[43]D5. In primary disease, generalised skin hyperpigmentation, most evident on sun-exposed areas, palmar creases, and mucosal surfaces, is pathognomonic and reflects high ACTH drive ^[42]D5[43]D5. Salt craving is reported by patients with mineralocorticoid deficiency ^[43]D5.

When a crisis supervenes, the picture accelerates. Abdominal pain, nausea, vomiting, and fever are common ^{[40]B2c[43]D5}. The cardinal haemodynamic sign is hypotension that may be postural or overt shock; in the largest inpatient database, 2.4% of patients died, and those who died were older (>60 years), had impaired consciousness at admission, or received insulin therapy (a marker of stress hyperglycaemia) ^[40]B2c. In children presenting with primary adrenal insufficiency, the most frequent findings at diagnosis are fatigue (67%), hyperpigmentation (50.4%), dehydration (33%), and hypotension (31%) ^[36]B2b.

Neurological Examination Findings

Altered mental status is a red flag: impaired consciousness was documented in 12 of 19 fatally ill patients in the Japanese nationwide series ^[40]B2c. Confusion, lethargy, or coma may be the presenting feature. In rare genetic forms, focal neurological signs dominate: the index case of a novel MRAP mutation presented with severe psychomotor retardation, myoclonic seizures, spastic quadriparesis, and microcephaly ^[11]C4. In immune‑checkpoint‑inhibitor‑induced secondary adrenal insufficiency (ICI‑SAI), neurological symptoms are less common but fatigue and malaise are universal ^[37]B2c.

Phenotypic Variants

Red Flags

• Unexplained hypotension in any patient with known AI, ICI therapy, adrenal surgery, or autoimmune disease
• Shock that does not correct with volume resuscitation - consider adrenal crisis even if vasopressors are required ^[48]C4[49]C4
• Hyponatremia, hyperkalemia, and hypoglycemia occurring together (especially in primary AI) ^{[36]B2b[42]D5}
• Impaired consciousness at presentation - a predictor of mortality ^[40]B2c
• Abdominal pain with hemodynamic instability - suspect adrenal hemorrhage ^[35]D5
• Peri‑operative setting after bilateral adrenalectomy or in Cushing’s disease post‑resection ^{[38]C4[39]C4[48]C4}
• Sudden deterioration after starting levothyroxine in a patient with undiagnosed AI - thyroxine accelerates cortisol clearance ^[50]C4

Atypical Presentations

Adrenal crisis can masquerade as other emergencies. In a patient with ectopic ACTH‑secreting thymic neuroendocrine tumour, the first sign of postoperative crisis was recurrent atrial tachycardia that resolved only after glucocorticoid administration ^[49]C4. Nelson’s syndrome may present with crisis 21 years after bilateral adrenalectomy, when the patient presents with anorexia, vomiting, and shock that mimics sepsis ^[48]C4. In antiphospholipid syndrome, bilateral adrenal hemorrhage is the dominant imaging phenotype (66.9% of cases) and adrenal insufficiency is the first manifestation in 73.6% of patients; strict adrenal crisis (hypotension with shock) occurs in 51.6% ^[44]C4. Pituitary apoplexy may present with sudden headache, visual deficits, and then adrenal crisis - immediate IV corticosteroids are indicated regardless of acuity ^[45]B2a. Immune‑checkpoint‑inhibitor‑induced hypothyroidism can unmask secondary AI when levothyroxine is started, precipitating crisis ^[50]C4.

Pearl: The triad of unexplained hyponatremia, hyperkalemia, and hypoglycemia in a stressed patient is adrenal crisis until proven otherwise - administer 100 mg IV hydrocortisone immediately without waiting for confirmatory labs.

Once clinical suspicion for adrenal crisis is raised, biochemical confirmation must proceed in parallel with emergency treatment. The diagnosis hinges on demonstrating absolute or relative cortisol deficiency, then localizing the defect to the adrenal glands (primary) or the pituitary-hypothalamic axis (secondary).

Laboratory Studies

Draw blood immediately for cortisol and ACTH before administering any glucocorticoid. A random serum cortisol <34 nmol/L (approximately 1.2 μg/dL) has 100% sensitivity for detecting a subnormal response to the 250‑μg cosyntropin stimulation test, making it a reliable bedside marker of severe adrenal insufficiency in the crisis setting ^[61]C4. Conversely, a random cortisol ≥348 nmol/L (12.6 μg/dL) provides 100% specificity for a normal cosyntropin response, effectively ruling out adrenal insufficiency ^[61]C4. Values between these cutoffs require dynamic testing. Simultaneous ACTH measurement distinguishes primary from secondary disease: a low cortisol paired with an ACTH >2× the upper limit of normal (typically >22 pmol/L) establishes primary adrenal insufficiency; a low or inappropriately normal ACTH points to secondary (central) adrenal insufficiency ^[43]D5[55]D5. In primary disease, plasma renin activity is elevated and aldosterone is low; in secondary disease, the renin-aldosterone axis is preserved.

Gold‑Standard Test: Cosyntropin Stimulation Test

When the random cortisol is intermediate (34-348 nmol/L) and the patient is hemodynamically stable enough to delay treatment, the 250‑μg cosyntropin (ACTH) stimulation test is the definitive diagnostic tool ^[56]D5. Administer 250 μg of cosyntropin intravenously (or intramuscularly) and measure serum cortisol at 0 and 30 or 60 minutes. A peak cortisol <500 nmol/L (18 μg/dL) is diagnostic of adrenal insufficiency ^[61]C4. In the crisis setting, however, treatment should never be delayed for the test, draw the baseline sample, give hydrocortisone , and perform the full stimulation test later when the patient has recovered.

Localization Imaging

Once the patient is stabilized, anatomic localization guides long‑term management . For primary adrenal insufficiency, non‑contrast adrenal CT identifies hemorrhage, calcification (tuberculosis, histoplasmosis ), metastases, or atrophy (autoimmune) ^[35]D5[55]D5. For secondary adrenal insufficiency, pituitary MRI with gadolinium is the study of choice to detect a mass, stalk thickening, or empty sella ^[55]D5[56]D5. Imaging is not required during the acute crisis but should be performed within the first weeks after diagnosis.

Diagnostic Algorithm

Step 1: Immediate random cortisol and ACTH. Step 2: If cortisol <34 nmol/L → diagnosis of AI; treat. If cortisol 34-348 nmol/L, proceed to cosyntropin test (if clinically safe). Step 3: ACTH level determines primary vs secondary. Step 4: Imaging after stabilization.

Pearl: In adrenal crisis, a random cortisol <34 nmol/L is sufficient to start treatment; do not wait for dynamic testing - the cosyntropin test can be completed later to confirm the diagnosis and guide chronic therapy ^[61]C4.

With the diagnosis confirmed, the next step is to stratify the patient's risk for adrenal crisis, a graded appraisal that directly shapes the aggressiveness of prevention, the threshold for stress dosing, and the intensity of follow-up. Risk is not uniform; it is determined by the underlying etiology, the presence of precipitating triggers, and the patient's physiologic reserve.

Identifying High-Risk Patients

Patients with primary adrenal insufficiency (PAI) carry a 2.5-fold higher mortality than the general population (pooled HR 2.51), with cardiovascular disease as the leading cause ^[69]A1a. In patients with congenital adrenal hyperplasia (CAH), the predominant cause of death is adrenal crisis itself ^[69]A1a. This distinction is clinically actionable: a CAH patient with a history of crisis requires a lower threshold for parenteral hydrocortisone and a lower threshold for emergency department referral.

Other high-risk groups include:

• Patients with bilateral adrenalectomy (BADx): long-term risk of adrenal crisis is a known complication, though surgical mortality is low (median 3%) and long-term mortality is low in Cushing's disease ^[38]C4.
• Patients with APS/SLE-spectrum disease: adrenal involvement is often hemorrhagic and bilateral; 51.6% of affected patients develop strict adrenal crisis, and hypotension is documented in 48.0% ^[44]C4.
• Patients on immune checkpoint inhibitors (ICIs): endocrine toxicities occur in 25% to 50% of ICI recipients; hypophysitis can present with adrenal crisis, and higher tumor mutational burden (TMB; 6.02 vs. 5.19 mut/Mb, P=0.002) and mutations in BABAM1, KDM5C, CDH4, and TAL1 are associated with increased risk ^{[57]D5[71]B2b}.
• Patients with AIDS and opportunistic infections: CD4 count <100 cells/µL, CMV infection, or tuberculosis are frequent triggers; two of three reported cases experienced adrenal crisis with intractable hypotension ^[66]C4.
• Patients on osilodrostat: prolonged adrenocortical blockade can persist 6 weeks to 9 months after drug cessation, necessitating ongoing adrenal function monitoring ^[70]C4.

Precipitating Triggers and Their Severity Gradient

Mortality Risk and Prognostic Factors

The standardized mortality ratio (SMR) for PAI is 2.49, with high heterogeneity (I²=97.9%) ^[69]A1a. In patients with CAH, the pooled HR is 2.88, and adrenal crisis is the leading cause of death ^[69]A1a. Adequate patient education on sick-day rules and stress dosing is protective, in a cohort of 279 AI patients during the COVID-19 pandemic, no adrenal crisis occurred, likely because patients were previously trained to adjust glucocorticoid doses ^[24]B3b.

Pearl: The single most modifiable risk factor for adrenal crisis is inadequate patient and family education on stress dosing, every AI patient should be able to recite the "sick-day rule" (double or triple the daily glucocorticoid dose during febrile illness) and carry an emergency injectable hydrocortisone kit.

Once severity is established, immediate management follows a time-critical pathway. Any patient with suspected adrenal crisis requires simultaneous initiation of hydrocortisone , fluid resuscitation, and supportive care, delay increases mortality ^[13]D5.

Step 1: Immediate Assessment and Disposition

Confirm the diagnosis clinically: hypotension (systolic BP < 100 mm Hg), nausea/vomiting, fever, altered mental status, and known adrenal insufficiency or risk factors ^[13]D5. Obtain a stat serum cortisol and ACTH if the diagnosis is uncertain, but do not wait for results to start treatment ^[43]D5. Insert two large-bore IV lines, draw blood for electrolytes, glucose, and CBC, and monitor cardiac rhythm. Admit to an intensive care unit if shock, severe electrolyte derangement, or altered consciousness is present ^[26]B2b.

Step 2: First-Line Intervention, Hydrocortisone and Fluids

• Hydrocortisone 100 mg IV bolus immediately, followed by 200 mg over 24 hours as continuous IV infusion (or 50 mg IV every 6 hours) ^[13]D5. High-dose hydrocortisone provides both glucocorticoid and mineralocorticoid activity, so fludrocortisone is not needed in the acute phase ^[43]D5.
• 0.9% saline 1000 mL IV over the first hour, then continue at 200-500 mL/hour based on hemodynamic response ^[13]D5. Add 5% dextrose if blood glucose < 70 mg/dL (3.9 mmol/L) ^[72]D5.
• Correct electrolyte abnormalities: hyperkalemia typically resolves with hydrocortisone and volume expansion; severe hyperkalemia (> 6.5 mmol/L) may require additional measures ^[44]C4.

Step 3: Escalation and Second-Line Measures

If hypotension persists after 1-2 L of saline and the first hydrocortisone dose, consider:

• Vasopressors (norepinephrine) for refractory shock ^[13]D5.
• Search for alternative causes: sepsis, myocardial infarction, adrenal hemorrhage (especially in anticoagulated patients or those with antiphospholipid syndrome) ^[35]D5.
• In patients on chronic glucocorticoid therapy, consider glucocorticoid-induced adrenal insufficiency as the precipitant ^[56]D5.

Step 4: Monitoring and Titration

• Measure blood pressure, heart rate, and urine output hourly.
• Check serum sodium, potassium, glucose, and creatinine every 4-6 hours until stable ^[13]D5.
• Once systolic BP > 100 mm Hg and the patient is tolerating oral intake, transition to oral hydrocortisone: 20 mg in the morning, 10 mg in the early afternoon (total 30 mg/day) ^[43]D5. Taper over 2-3 days to the patient's usual maintenance dose (typically 15-25 mg/day in divided doses) ^[63]D5.
• If primary adrenal insufficiency, add fludrocortisone 0.05-0.2 mg orally once daily when the patient is eating and volume-replete ^[42]D5.

Step 5: Prevention and Transition to Long-Term Care

Before discharge, every patient must receive:

• A steroid emergency card and a parenteral hydrocortisone emergency kit (100 mg vial for IM/SC self-injection) ^[43]D5.
• Written sick-day rules: double the daily hydrocortisone dose for fever > 38°C, triple for > 39°C; for vomiting or diarrhea, administer IM/SC hydrocortisone 100 mg and seek emergency care ^[72]D5.
• Education on precipitating factors: infections, surgery, trauma, emotional stress, and strenuous physical activity ^[23]B2b.
• A follow-up appointment with an endocrinologist for long-term management (see next section).

Dosing Table: Hydrocortisone in Adrenal Crisis

Management Algorithm

Caption: Figure 1: Acute management algorithm for adrenal crisis (adapted from ^[13]D5 and ^[43]D5).

Controversies and Guideline Disagreement

Pearl: In suspected adrenal crisis, administer hydrocortisone 100 mg IV bolus and 1 L saline within the first hour without waiting for confirmatory labs; this single action reduces mortality from approximately 0.5 per 100 patient-years to near-zero in the acute setting ^[13]D5, ^[23]B2b.

Once the acute crisis is controlled, the cornerstone of long-term management is glucocorticoid replacement that mimics physiological cortisol secretion while avoiding over-replacement, supplemented by mineralocorticoid therapy when needed. The goal is to restore eucortisolemia, suppress excess ACTH in congenital adrenal hyperplasia (CAH), and address the underlying structural or autoimmune process when possible.

Glucocorticoid Replacement Therapy

Hydrocortisone is the preferred agent because its short half-life allows approximation of the circadian rhythm, though no single regimen fully replicates normal cortisol profiles. Dosing is individualized: for adults with primary or secondary adrenal insufficiency, typical regimens use two to three divided doses, with the largest given on waking. For patients with classic CAH, median hydrocortisone doses at study entry are 30 mg/day, reduced to 20 mg/day after 24 weeks with improved biochemical control; this dose remains stable thereafter ^[21]C4. Modified-release hydrocortisone capsules (MRHC, Chronocort) achieve a once-daily morning dose and, in open-label follow-up over 4 years, maintained disease control in the majority of patients: 71% had serum 17-hydroxyprogesterone < 4 times the upper limit of normal (ULN) and 90% had androstenedione < ULN ^[21]C4. The adrenal crisis rate on MRHC was 3.9 per 100 patient-years, below previously reported rates for CAH ^[21]C4.

Mineralocorticoid Replacement

In primary adrenal insufficiency, fludrocortisone is essential. Dose is titrated to normokalemia, normal plasma renin activity, and blood pressure. Starting and target doses vary, and the provided references do not report a specific numeric range; adjustment is guided by clinical and biochemical response. In CAH, mineralocorticoid status must be assessed: patients with salt-wasting forms require fludrocortisone and salt supplementation, especially in infancy ^[72]D5.

Monitoring and Treatment Targets

Optimal replacement is judged by clinical well-being, absence of features of over- or under-replacement, and biochemical markers. For CAH, serum 17-hydroxyprogesterone and androstenedione are the key monitoring tools. A single blood sample drawn between 09:00 and 13:00 h is sufficient: after 4 years of MRHC therapy, 90% of patients had androstenedione within the normal range ^[21]C4. Symptoms of undertreatment include fatigue, hyperandrogenic symptoms (in CAH), salt craving, and orthostatic hypotension; overtreatment manifests as weight gain, hypertension , osteoporosis, and growth suppression in children ^[72]D5.

Stress Dosing and Sick-Day Rules

Preventing adrenal crisis requires prompt glucocorticoid dose escalation during intercurrent illness. Patients must be educated to double the daily hydrocortisone dose for fever >38°C and triple it for fever >39°C ^[72]D5. If vomiting or severe diarrhea prevents oral intake, immediate administration of 100 mg hydrocortisone intramuscularly or subcutaneously - from an emergency injection kit - is required, followed by urgent medical evaluation ^[72]D5. For major stress (surgery, sepsis, trauma), continuous intravenous hydrocortisone infusion at 200 mg over 24 h, preceded by a 50-100 mg intravenous bolus, best maintains cortisol concentrations in the range observed during physiological stress; intermittent bolus administration is inferior ^[80]B2b. Two small Cochrane reviews (2009 and 2012) found insufficient evidence to support or refute supplemental perioperative steroids, but these were limited by small sample sizes and high risk of bias ^{[74]A1a[75]A1a}. Current clinical practice - endorsed by guideline recommendations - continues to use stress dosing based on the pharmacokinetic data from ^{[80]B2b [43]D5}.

Definitive Therapies

For ACTH-dependent Cushing’s syndrome, bilateral adrenalectomy provides rapid control of hypercortisolism but creates permanent adrenal insufficiency and carries a long-term risk of Nelson’s syndrome (corticotrope tumor progression and hyperpigmentation) ^[38]C4. In patients with Cushing’s disease treated with the steroidogenesis inhibitor osilodrostat, adrenocortical blockade can persist for 6 weeks to 9 months after drug discontinuation, demanding continued adrenal monitoring to avoid crisis ^[70]C4. In autoimmune Addison’s disease, a pilot study of rituximab (B-cell depletion) in six patients within 4 weeks of diagnosis showed sustained recovery of cortisol secretion in one patient, who remained steroid-free at 27 months; the other five did not improve ^[54]C4. Although not standard therapy, immunomodulation at disease onset may be a future avenue.

Education and Prevention

Despite thorough training, adrenal crises still occur at a rate of 8.3 per 100 patient-years in educated patients, with gastrointestinal infection and fever as the most common triggers ^[23]B2b. Every patient should carry a steroid emergency card and a parenteral hydrocortisone kit, and receive repeated instruction on stress dosing and injection technique ^[43]D5. The first joint European Society of Endocrinology/Endocrine Society guideline on glucocorticoid-induced adrenal insufficiency provides additional structured tapering protocols ^[51]D5[53]D5.

Pearl: In long-term adrenal insufficiency management, the foundation is physiologic glucocorticoid replacement with stress-dose escalation for illness; for CAH, modified-release hydrocortisone can improve biochemical control while reducing the total daily dose and crisis rate (3.9 per 100 patient-years, ^[21]C4).

After decades of reliance on immediate-release hydrocortisone dosed two to three times daily, the recognition that conventional regimens fail to replicate the circadian cortisol rhythm has driven a series of therapeutic innovations. The current treat-to-target strategy emerged from a stepwise accumulation of clinical evidence, beginning with the isolation of cortisone in the 1940s and the first successful replacement therapy for Addison disease. Fludrocortisone was added in the 1950s to address mineralocorticoid deficiency in primary adrenal insufficiency, and the standard oral hydrocortisone dose of 15-25 mg daily became the mainstay, often split into two or three divided doses ^[92]D5.

Limitations of Conventional Therapy

Despite maintaining adequate 24-hour cortisol exposure (AUC₀₋₂₄ₕ), conventional regimens produce cortisol concentrations outside the physiological 90% reference range in 50% of children, 55-65% of infants, and 70-75% of neonates, with low levels most prevalent before the next dose ^[79]C4. This non-physiological profile contributes to the narrow therapeutic window, where subclinical over- or under-replacement may increase long-term morbidity and mortality ^[15]D5. The lack of a reliable biomarker to guide dosing further compounds the problem, leaving clinicians to titrate based on clinical symptoms and time of day ^[15]D5.

Modified-Release Chronotherapeutics

The first major advance was the development of modified-release hydrocortisone formulations. Plenadren, a once-daily dual-release tablet, and Chronocort (hydrocortisone modified-release hard capsules, MRHC) were designed to mimic the circadian cortisol rise, with a delayed peak in the early morning. In an open-label follow-up study of 91 patients with classic congenital adrenal hyperplasia , MRHC treatment reduced the median hydrocortisone dose from 30 mg/day to 20 mg/day after 24 weeks, with stable dosing thereafter ^[21]C4. Biochemical control improved: after 4 years, 71% of patients had serum 17-hydroxyprogesterone <4-fold the upper limit of normal and 90% had androstenedione <ULN ^[21]C4. The incidence of adrenal crisis fell to 3.9 crises per 100 patient years, lower than the previously reported rates in CAH cohorts ^[21]C4. Modified-release therapy also improved fertility, with 13.5% of women <50 years becoming pregnant and 13.8% of men fathering a pregnancy ^[21]C4.

Targeted Therapy for Congenital Adrenal Hyperplasia

For patients with CAH, bilateral adrenalectomy was historically offered to those with unsatisfactory medical control, large adrenal tumors, or hyperplasia, but it carried risks of increased adrenal crisis and adrenal rest tumor growth ^[91]D5. The approval of crinecerfont, a corticotropin-releasing factor type 1 receptor (CRF1) antagonist, in December 2024, and the advanced phase 3 study of atumelnant, a melanocortin-2 receptor (MC2R) antagonist, now provide pharmacologic alternatives to reduce ACTH-driven androgen excess without supraphysiological glucocorticoid doses ^[91]D5. These agents may obviate the need for adrenalectomy in many patients, though cost and availability remain barriers ^[91]D5.

Recognition of Glucocorticoid-Induced Adrenal Insufficiency

Glucocorticoid-induced adrenal insufficiency is now recognized as the most common form of adrenal insufficiency, affecting at least 1% of the population on chronic glucocorticoid therapy ^[51]D5[53]D5. The risk depends on dose, duration, potency, route, and individual susceptibility. Tapering strategies evolved from rapid withdrawal above the physiological range to a slower taper once replacement doses are reached, guided by the understanding that HPA axis recovery varies greatly among individuals ^[51]D5[53]D5.

Emerging Causes: Immune Checkpoint Inhibitors

More recently, immune checkpoint inhibitors (ICIs) have emerged as a novel cause of adrenal crisis, with cases of anti-PD1-induced autoimmune polyendocrine syndrome type 2 presenting as full-triad adrenal crisis and ketoacidosis ^[89]C4[90]C4. Timely recognition and hormone replacement are critical to prevent fatal outcomes and allow continued cancer therapy when possible ^[89]C4.

Pearl: The evolution from fixed-dose hydrocortisone to chronotherapeutic and targeted strategies represents the most significant advance in adrenal insufficiency management in the last 50 years, reducing the adrenal crisis incidence by nearly half in CAH cohorts while improving biochemical control and fertility.

History has taught us to suspect adrenal crisis beyond isolated adrenal disease; it is the final common pathway of multiglandular syndromes, genetic defects, and cross-axis perturbations that demand syndromic screening.

Autoimmune Polyendocrine Syndromes (APS-1 and APS-2)

Autoimmune polyendocrine syndrome type 1 (APS-1, also called APECED) is a monogenic disorder caused by biallelic AIRE mutations. The classic triad is chronic mucocutaneous candidiasis , hypoparathyroidism , and primary adrenal insufficiency (PAI). In a large pediatric PAI cohort (n=803), APS-1 accounted for 3.1% of cases ^[36]B2b. Among women with APS-1 who become pregnant, 36% have PAI, and adrenal crisis during pregnancy is a rare but catastrophic event: one such crisis led to intrauterine fetal death at gestational week 34 ^[95]B2b. Premature ovarian insufficiency (POI) occurs in 40% at a median age of 28 years, and only 15% of women over 16 years had a livebirth, reflecting reduced fertility ^[95]B2b.

APS-2 is more common than APS-1, typically presenting in adulthood with Addison's disease plus autoimmune thyroid disease and/or type 1 diabetes. Immune checkpoint inhibitors (ICPis) can trigger an APS-2 phenotype; among 30 reported cases, endocrine irAEs included adrenalitis, thyroiditis, and type 1 diabetes ^[58]D5. Patients with the risk allele HLA-DR4 require close monitoring, after one ICPi-induced endocrinopathy, screening for others is mandatory to prevent adrenal crisis ^[58]D5.

Genetic Syndromes and Monogenic PAI

In a cohort of 59 children with rare causes of PAI (excluding 21-hydroxylase deficiency), 64% had monogenic disorders including X-linked adrenoleukodystrophy, adrenal hypoplasia congenita, and triple A syndrome ^[77]B2b. Acute adrenal crisis occurred in 45% of these patients, usually due to poor treatment adherence, and overall mortality was 10% ^[77]B2b. Congenital adrenal hyperplasia (21-OHD) remains the most common cause of pediatric PAI (85% of 803 cases), with an adrenal crisis rate of 2.7 per 100 patient-years ^[36]B2b.

Co-Axis Effects: Adrenal Hemorrhage and Antiphospholipid Syndrome

Bilateral adrenal hemorrhage is a thrombotic emergency in antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE). In a pooled analysis of 155 patients, 51.6% presented with strict adrenal crisis, 86.3% had bilateral involvement, and 66.9% had hemorrhage-dominant imaging ^[44]C4. Adrenal insufficiency was the first manifestation in 73.6% of informative cases ^[44]C4. Management requires dual-pathway therapy: anticoagulation for the thrombotic risk and glucocorticoid replacement for adrenal insufficiency ^[44]C4[98]C4. Adrenal hemorrhage is also increasingly reported in COVID-19 infection and vaccine-induced immune thrombotic thrombocytopenia ^[35]D5.

Table: Key Syndromes Associated with Adrenal Crisis Risk

Pregnancy and Syndromic Risk

While pregnancy management is detailed elsewhere, patients with APS-1 or CAH require heightened surveillance. PAI can develop de novo during pregnancy, as shown by one patient who developed PAI and adrenal crisis leading to stillbirth ^[95]B2b. In APECED, POI severely limits fertility, but spontaneous pregnancies can occur; careful monitoring of 21-hydroxylase autoantibodies is recommended ^[95]B2b.

Pearl: In any patient with one autoimmune endocrine disorder, screen for concurrent adrenal insufficiency, especially before initiating immune checkpoint inhibitors or in the setting of unexplained hypotension, because adrenal crisis is the preventable endpoint of missed polyendocrine disease.

From the preceding discussion of syndromic and genetic contexts, it is clear that the consequences of adrenal insufficiency extend far beyond the acute crisis. Chronic cortisol deficiency, even with replacement therapy, leaves patients vulnerable to a spectrum of long-term complications that drive excess morbidity and mortality.

Mortality and Cardiovascular Risk

Mortality in primary adrenal insufficiency (PAI) is increased 2.5-fold compared with the reference population (pooled HR 2.51, 95%; pooled SMR 2.49) ^[69]A1a. In a UK cohort of 6821 patients, the all-cause mortality HR was 1.68, higher in primary (HR 1.83) than secondary disease (HR 1.52) ^[29]B2b. The leading cause of death is cardiovascular disease (HR 1.54, 95% CI 1.32-1.80), followed by malignancy and respiratory disease ^[29]B2b. Adrenal crisis contributes to 10% of all deaths ^[29]B2b. Mortality from infection is markedly elevated (HR 4.00) ^[29]B2b. Older adults (>60 years) carry the highest age-specific incidence of adrenal crisis, with rates doubling between ages 60-69 and ≥80 years ^{[26]B2b[33]D5}. (NNT for prevention of cardiovascular death not calculable from reported data.)

Bone Health

Glucocorticoid replacement dose directly influences bone mineral density (BMD). In a prospective study of 57 PAI and 33 CAH patients, a reduction in daily hydrocortisone equivalent dose (mean from 30.8 to 21.4 mg) led to a significant increase in lumbar spine and hip Z-scores over 2 years, whereas a dose increase reduced femoral neck Z-scores ^[99]C4. No adrenal crises occurred during the dose-reduction period ^[99]C4. In classic CAH, low BMD is common, related to cumulative glucocorticoid exposure, and screening by dual-energy x-ray absorptiometry is recommended ^[72]D5. Prednisolone impairs BMD more than hydrocortisone ^[72]D5.

Metabolic and Cardiovascular Risk Factors

Patients with CAH have higher frequencies of insulin resistance, obesity, type 2 diabetes, hypertension , and dyslipidemia compared with controls ^[72]D5. The risk of type 2 diabetes is greater in females than males with CAH ^[72]D5. Cardiometabolic complications are primarily attributed to obesity and glucocorticoid overtreatment ^[72]D5. In PAI, similar risks arise from unphysiological replacement regimens ^[63]D5. Avoidance of overtreatment (e.g., suppressing 17-hydroxyprogesterone completely) is essential.

Infection Risk and Adrenal Crisis Recurrence

Infections are the major precipitant of adrenal crisis, occurring in 20% of crises ^[23]B2b. Even in educated patients, the incidence of adrenal crisis is 8.3 per 100 patient-years ^[23]B2b. A prior crisis increases the risk of another (OR 2.85) ^[23]B2b. Adrenal crisis contributed to 0.5 deaths per 100 patient-years ^[23]B2b. In COVID-19 , adequately trained AI patients had similar symptom incidence and severity as controls, and no adrenal crises were reported ^[24]B3b. In pediatric PAI (non-CAH), adrenal crisis occurred in 45% of patients, often due to poor adherence ^[77]B2b.

Pregnancy and Fertility

Women with classic CAH have reduced fertility: birth rate 25.4% vs 45.8% in controls, with the lowest rate (8.1%) in salt-wasting CAH ^[72]D5. In autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), 43 women had 83 pregnancies; 72% led to delivery, but one adrenal crisis caused stillbirth ^[95]B2b. Adrenal insufficiency during pregnancy requires careful monitoring and stress dosing during labor ^[60]D5. Assisted reproduction with controlled ovarian hyperstimulation carries an unrecognized risk of adrenal crisis due to accelerated estrogen stimulation ^[60]D5.

Quality of Life and Psychosocial Morbidity

Despite standard replacement therapy, patients with AI report impaired subjective health status, reduced work capacity, and lower quality of life ^[63]D5[42]D5. In CAH, women have lower marriage rates, later sexual debut, and higher use of sick leave and disability pension ^[72]D5. Genital surgery in virilized females may lead to sexual dysfunction, vaginal stenosis, and reduced clitoral sensitivity ^[72]D5.

Long-term Sequelae in Specific Populations

• Pediatric PAI: Growth impairment is common; final height in non-CAH PAI is -1.1 SDS (males) and -0.4 SDS (females) ^[77]B2b. Excess weight occurs in 27% ^[77]B2b.
• Steroid-induced AI: In children with nephrotic syndrome, AI prevalence ranges 5.9-92.9% depending on testing method; risk increases with cumulative steroid exposure ^[4]B2a.

Pearl: The leading cause of death in adrenal insufficiency is cardiovascular disease, not adrenal crisis, yet crisis prevention and minimizing glucocorticoid overtreatment are the two modifiable levers that can reduce both excess mortality and long-term bone and metabolic complications ^{[29]B2b[69]A1a[99]C4}.

Despite optimal glucocorticoid replacement, patients with adrenal insufficiency carry a 2.5-fold increased mortality compared to the general population (pooled HR 2.51) ^[69]A1a. Cardiovascular disease is the leading cause, but adrenal crisis itself contributes substantially, mortality rate from crisis is 0.5 per 100 patient-years ^[13]D5, and for every 200 crises approximately one death occurs ^[25]B2a. Congenital adrenal hyperplasia (CAH) carries a similar excess risk (HR 2.88), with crisis the dominant cause of death in this subgroup ^[69]A1a.

Risk Factors for Recurrent Crisis

Crisis incidence in chronic adrenal insufficiency is 6.3 per 100 patient-years (42% of patients report at least one crisis) ^[32]B2c. Risk factors include:

• Gastrointestinal infection or fever, triggers 45% of crises ^[32]B2c
• Female sex and diabetes insipidus in secondary adrenal insufficiency (OR 2.18 and 2.71, respectively) ^[32]B2c
• Age >60 years, crisis incidence doubles between ages 60-69 and ≥80 years ^[33]D5
• Higher daily glucocorticoid dose and reduced frequency of self‑reported dose adjustment, proactive up‑titration is protective, regardless of biologic vulnerability ^[9]B3b

Prevention: Education and Behavioural Interventions

All current interventions focus on patient education, but none has demonstrated a reduction in crisis frequency ^[25]B2a. Knowledge improves immediately after structured teaching (score 17→23/29, P<0.001) and is sustained at 6-9 months ^[103]C4; however, knowledge does not reliably translate into dose adjustment during illness, a persistent knowledge‑behaviour gap ^[25]B2a. Only one study showed transient gains in self‑injection confidence (91% post‑training vs 68% at baseline), but confidence waned by 6-9 months ^[103]C4. Effective prevention appears to require repeated, hands‑on training that targets not just knowledge but also skills, emotional readiness, and social support ^[104]D5.

Practical Preventive Measures (Sick Day Rules)

Every patient must carry a steroid emergency card and possess a parenteral hydrocortisone kit. Clinician training is equally critical, deficits in clinician knowledge of stress dosing are a recognised and modifiable risk factor ^[28]D5.

Screening and Family Cascade Testing

Newborn screening for CAH is now >50% globally, but gaps persist across under‑resourced regions ^[101]D5. For males with adrenoleukodystrophy identified by newborn screen, adrenal function should be assessed at diagnosis and regularly thereafter to prevent first crisis ^[52]D5. In patients with immune checkpoint inhibitor‑induced hypophysitis or primary adrenal insufficiency, prompt endocrine referral and steroid coverage before further ICI cycles are essential ^[50]C4[57]D5. Family cascade testing (CYP21A2 genotyping) is indicated for CAH, but access to genetic counselling remains limited, especially in low‑resource settings ^[101]D5.

Pearl: The single most modifiable risk factor for adrenal crisis is the patient's failure to increase glucocorticoid dose during intercurrent illness, repeated, hands‑on training in stress dosing and self‑injection, rather than passive education, is needed to close the knowledge‑behaviour gap ^{[25]B2a[103]C4}.

Prevention strategies must be tailored across the lifespan, as age, pregnancy, and immunosuppression fundamentally alter the risk of adrenal crisis and modify treatment thresholds.

Pediatrics

Younger age at diagnosis is an independent risk factor for adrenal crisis (relative risk 0.93 per year; 95%) ^[22]B2b. In a prospective cohort of pediatric-onset adrenal insufficiency, the incidence of adrenal crisis was 4.27 per 100 patient-years, with infections and gastrointestinal illness the most common triggers ^{[22]B2b[106]B2b}. Hypoglycemia is a particular hazard in children with congenital adrenal hyperplasia (CAH) because of concomitant epinephrine deficiency ^[106]B2b.

Hydrocortisone is the glucocorticoid of choice in children to avoid growth suppression; prednisolone and dexamethasone are associated with compromised final height and increased body mass index ^{[72]D5[76]A1a}. Typical maintenance doses range from 8 to 10 mg/m²/day divided into three doses, with the highest dose given in the morning ^[72]D5. During febrile illness, the daily dose should be doubled for fever >38°C and tripled for >39°C ^[72]D5. Vomiting or severe diarrhea requires intramuscular or intravenous hydrocortisone (100 mg for children >1 year; 50 mg for infants) and hospital admission ^{[72]D5[102]D5}.

Newborn screening for adrenoleukodystrophy (ALD) should prompt assessment of adrenal function at diagnosis, with regular monitoring to identify evolving adrenal insufficiency and prevent crisis ^[52]D5. Steroid-induced adrenal insufficiency is also common in children with nephrotic syndrome who receive prolonged corticosteroids; stress dosing is required during intercurrent illness ^[4]B2a.

Pregnancy

Adrenal crisis occurs in 18.8% of pregnancies in women with primary adrenal insufficiency (PAI), with 24% of women experiencing at least one crisis during pregnancy ^[107]B2b. Despite documented endocrinology input, only 41% of women received an increased hydrocortisone dose in pregnancy, and only 39.6% carried a steroid emergency card ^[107]B2b. These data indicate that inadequate dose adjustment is a major preventable contributor to crisis.

• Dose adjustments: The prepregnancy glucocorticoid dose can be continued in the first trimester. In the second and third trimesters, the dose should be increased by 20-40% to account for rising cortisol-binding globulin and placental metabolism ^[59]D5[60]D5. Hydrocortisone or prednisolone are preferred; dexamethasone crosses the placenta and should be avoided ^[72]D5.
• Stress dosing during labor: Administer 100 mg hydrocortisone IV bolus at onset of labor, followed by 200 mg continuous IV infusion over 24 hours ^[80]B2b. After delivery, taper to the prepregnancy dose over 2-3 days.
• Delivery planning: Cesarean section is recommended for women with prior vulvovaginal surgery (e.g., CAH feminizing surgery) to avoid perineal trauma ^[72]D5. The cesarean rate in PAI is 63.9%, and preterm birth occurs in 21.2% ^[107]B2b.
• Fertility and assisted reproduction: Women with CAH have reduced fertility, especially those with salt-wasting forms (birth rate 8.1% vs 45.8% in controls) ^[72]D5. Controlled ovarian hyperstimulation for assisted reproduction creates a rapid estrogen surge that can precipitate adrenal crisis; close collaboration between endocrinologists and reproductive specialists is essential ^[60]D5.
• Breastfeeding : Hydrocortisone is secreted in low levels in breast milk and is considered safe; no dose adjustment is needed ^[59]D5.

Elderly

Adults >80 years have the highest incidence of adrenal crisis hospitalization, driven largely by an increase in central adrenal insufficiency from expanding glucocorticoid and immunotherapy use ^[26]B2b. Advanced age, male sex, and unspecified etiology of adrenal insufficiency are independent predictors of in-hospital mortality and 1-year death ^[26]B2b. Comorbidities such as diabetes, hypertension , and cardiovascular disease are common in this group and may lower the threshold for crisis. Maintenance glucocorticoid doses should be reduced to avoid overtreatment (osteoporosis, fractures, hyperglycemia), but stress doses during acute illness should follow the same protocols as younger adults. Delirium and hypoglycemia may be the presenting signs of adrenal crisis in the elderly, requiring a high index of suspicion.

Immunocompromised

Patients with adrenal insufficiency who are also immunocompromised, whether from glucocorticoid therapy itself, concomitant immunosuppressive drugs, or underlying disease, are at increased risk of infections that trigger adrenal crisis ^{[23]B2b[32]B2c}. In the setting of COVID-19 , children with adrenal insufficiency did not show increased susceptibility or severity compared with controls, provided sick-day rules were followed ^[30]B2b. For all immunocompromised patients, early stress dosing at the first sign of infection is critical. Vaccination against influenza, pneumococcus, and SARS-CoV-2 should be strongly encouraged. Drug interactions that alter glucocorticoid metabolism (e.g., rifampin , azole antifungals) require proactive dose adjustment ^[102]D5.

Pearl: Older adults (>80 years) have the highest incidence of adrenal crisis hospitalization, with central AI and comorbidities as major drivers.