10.3 Pituitary Emergencies, Adrenal Excess & Critical Illness-Related Corticosteroid Insufficiency

ABIM Critical Care Medicine Study Guide Exam

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1 Chapter 1: Exam Orientation: Format, Blueprint & Study Strategy

1.1 ABIM Critical Care Medicine Exam: Format, Blueprint & Study Strategy

2 Chapter 2: Acute Respiratory Failure & ARDS

2.1 ARDS Definition, Pathophysiology & Phenotypes 2.2 Lung-Protective Mechanical Ventilation 2.3 Refractory ARDS: Prone Positioning, Neuromuscular Blockade & VV-ECMO

3 Chapter 3: Obstructive Airways, Pulmonary Vascular & Pleural Emergencies

3.1 Severe Asthma & COPD Exacerbations in the ICU 3.2 Massive & Submassive Pulmonary Embolism 3.3 Pulmonary Hypertension & Right Ventricular Failure in the ICU 3.4 Massive Hemoptysis, Complex Pleural Effusions & Thoracic Drainage

4 Chapter 4: Airway, Parenchymal & Nonthrombotic Pulmonary Emergencies

4.1 Airway Management, Upper-Airway Obstruction & Artificial-Airway Complications 4.2 Diffuse Alveolar Hemorrhage, Interstitial Lung Disease, Pulmonary Vasculitis & Noncardiogenic Edema 4.3 Severe Community-Acquired & Viral Pneumonia 4.4 Nonthrombotic Embolism (Air, Fat, Amniotic Fluid, Tumor, Septic) & Acute Chest Syndrome

5 Chapter 5: Mechanical Ventilation Modes, Dyssynchrony & Liberation

5.1 Mechanical Ventilator Modes & Advanced Breath Delivery 5.2 Patient-Ventilator Dyssynchrony & Waveform Analysis 5.3 Ventilator Liberation, Spontaneous Breathing Trials & Post-Extubation Support

6 Chapter 6: Shock Syndromes & Hemodynamic Principles

6.1 Shock Classification, Cellular Pathophysiology & Biomarkers 6.2 Hemodynamic Monitoring: Arterial Lines, CVP & Pulmonary Artery Catheter 6.3 Dynamic Assessment of Fluid Responsiveness & Resuscitation Targets

7 Chapter 7: Vasoactive Therapies & Mechanical Circulatory Support

7.1 Vasopressors & Inotropes: Pharmacology & Clinical Titration 7.2 Temporary Mechanical Circulatory Support: IABP, Impella & TandemHeart 7.3 Venoarterial ECMO (VA-ECMO) & Differential Hypoxemia 7.4 Post-Cardiac Arrest Care, Targeted Temperature Management & Neuroprognostication

8 Chapter 8: Acute Kidney Injury & Renal Replacement Therapy

8.1 KDIGO AKI Classification, Etiologies & Diagnostic Evaluation 8.2 Continuous Renal Replacement Therapy (CRRT) vs Intermittent Hemodialysis 8.3 Indications & Timing for RRT in Critical Illness: AKIKI & STARRT-AKI

9 Chapter 9: Electrolyte, Acid-Base & Endocrine Emergencies

9.1 Severe Dysnatremias: Hyponatremia, Hypernatremia & Osmotic Demyelination 9.2 Potassium, Calcium, Magnesium & Phosphate Disorders 9.3 Complex & Mixed Acid-Base Disorders: Boston vs Copenhagen vs Stewart 9.4 Endocrine Crises: DKA, HHS, Thyroid Storm, Myxedema Coma & Adrenal Crisis

10 Chapter 10: Glycemic Control, Hyperammonemia, Pituitary & Adrenal Disorders

10.1 ICU Glycemic Control & Severe Hypoglycemia 10.2 Non-Hepatic Hyperammonemia & Metabolic Encephalopathy 10.3 Pituitary Emergencies, Adrenal Excess & Critical Illness-Related Corticosteroid Insufficiency

11 Chapter 11: Acute Coronary Syndromes & Cardiac Arrhythmias

11.1 Acute Coronary Syndromes & Mechanical Complications of Myocardial Infarction 11.2 Critical Tachyarrhythmias: Atrial Fibrillation with RVR, VT & VF 11.3 Critical Bradyarrhythmias, Conduction Blocks & Temporary Cardiac Pacing

12 Chapter 12: Acute Heart Failure, Valvular & Pericardial Emergencies

12.1 Acute Decompensated Heart Failure & Cardiogenic Pulmonary Edema 12.2 Acute Valvular Regurgitation & Prosthetic Valve Emergencies 12.3 Pericardial Tamponade & Acute Aortic Syndromes

13 Chapter 13: Myocardial Disease, Hypertensive & Cardiac Device Emergencies

13.1 Fulminant Myocarditis, Stress & Peripartum Cardiomyopathy, and Hypertrophic Cardiomyopathy 13.2 Hypertensive Emergencies & Ruptured Abdominal Aortic Aneurysm 13.3 Implanted Cardiac Devices, LVAD Emergencies & Electrical Storm

14 Chapter 14: Sepsis & Systemic Infectious Diseases

14.1 Sepsis-3 Definitions & Surviving Sepsis Campaign 2026 Guidelines 14.2 Refractory Septic Shock & Adjunctive Therapies 14.3 Multidrug-Resistant Pathogens & Antimicrobial Stewardship in the ICU

15 Chapter 15: ICU-Acquired & Severe Focal Infections

15.1 Hospital-Acquired & Ventilator-Associated Pneumonia 15.2 Central Line-Associated Bloodstream Infections & Catheter-Associated UTIs 15.3 Intra-Abdominal Sepsis, Necrotizing Soft Tissue Infections & CNS Infections

16 Chapter 16: Focal, Special-Host & Systemic Infections

16.1 CNS Infections Beyond Bacterial Meningitis: Encephalitis, Brain Abscess & Epidural Abscess 16.2 Infections in the Immunocompromised Host, Tropical & Bioterror Infections 16.3 Infective Endocarditis, Device Infections & Other Focal Cardiovascular Infections 16.4 Antimicrobial Pharmacokinetics, Allergy, Toxicity & Infection Prevention 16.5 Gastrointestinal & Hepatobiliary Infections: Fulminant C. difficile, Typhlitis, CMV Colitis & Abscesses

17 Chapter 17: Neurocritical Care & Coma

17.1 Coma, Altered Mental Status & Acute Delirium in the ICU 17.2 Status Epilepticus & Non-Convulsive Status Epilepticus 17.3 Acute Ischemic Stroke & Intracranial Hemorrhage

18 Chapter 18: Cerebrovascular Syndromes, Encephalopathy & Withdrawal States

18.1 Cerebral Venous Sinus Thrombosis, PRES & Reversible Cerebral Vasoconstriction Syndrome 18.2 Alcohol & Sedative Withdrawal, Wernicke Encephalopathy & Drug-Induced Encephalopathy

19 Chapter 19: Intracranial Hypertension & Neuromuscular Weakness

19.1 Intracranial Pressure Monitoring, Cerebral Perfusion & Tiered ICP Management 19.2 Acute Neuromuscular Respiratory Failure, ICU-Acquired Weakness & Brain Death Determination

20 Chapter 20: Traumatic Brain Injury, Spinal Cord Injury & Toxin-Mediated Paralysis

20.1 Traumatic Brain Injury Management & Paroxysmal Sympathetic Hyperactivity 20.2 Acute Spinal Cord Injury, Neurogenic Shock & Autonomic Dysreflexia 20.3 Toxin-Mediated Paralysis & Neuromuscular Crises: Botulism, Tetanus, Tick Paralysis & Myasthenic Crisis

21 Chapter 21: Gastrointestinal, Hepatic & Abdominal Emergencies

21.1 Acute Upper & Lower Gastrointestinal Bleeding in the ICU 21.2 Acute Liver Failure & Severe Acute Pancreatitis 21.3 Abdominal Compartment Syndrome & Acute Mesenteric Ischemia

22 Chapter 22: Luminal GI Emergencies & Complications of Cirrhosis

22.1 Esophageal, Gastric & Bowel Emergencies: Perforation, Obstruction, Ogilvie Syndrome & Colonic Ischemia 22.2 Complications of Cirrhosis: Alcohol-Associated Hepatitis, Hepatorenal Syndrome & Pulmonary Vascular Syndromes

23 Chapter 23: Trauma, Burns & Perioperative Critical Care

23.1 Polytrauma Resuscitation, Damage Control & Massive Transfusion 23.2 Severe Burn Injury, Inhalation Injury & Environmental Emergencies 23.3 Perioperative Critical Care for High-Risk Surgical Patients

24 Chapter 24: Thoracic Trauma, Environmental Injury & Obstetric Critical Care

24.1 Thoracic Trauma: Flail Chest, Pulmonary Contusion, Great Vessel & Tracheobronchial Injury 24.2 Environmental Injury: Drowning, Diving, Altitude, Heat, Cold, Electrical & Radiation 24.3 Obstetric & Genitourinary Emergencies and the Physiology of Pregnancy

25 Chapter 25: Transplantation, Donor Management & Post-Cardiac Surgery Care

25.1 Solid Organ Transplant Recipients & Deceased Donor Management 25.2 Post-Cardiac Surgery Critical Care: Bleeding, Tamponade, Low Output & Vasoplegia

26 Chapter 26: Hematologic Emergencies, Toxicology, Critical Ultrasound & ICU Liberation

26.1 Hematologic Emergencies in the ICU: HIT, DIC, TMA & Anticoagulant Reversal 26.2 Critical Care Toxicology, Toxidromes & Specific Antidotes 26.3 Critical Care Point-of-Care Ultrasound (POCUS) 26.4 ICU Liberation, Analgosedation, Goals of Care & Critical Care Ethics

27 Chapter 27: Transfusion Medicine, Hematologic & Oncologic Disorders

27.1 Transfusion Medicine: Products, Thresholds, Reactions & Apheresis 27.2 Red and White Cell Disorders, Hemoglobinopathies, Factor Deficiencies & Hypercoagulable States 27.3 Oncologic Emergencies, Hematopoietic Cell Transplant Complications & Cellular Therapy Toxicity

28 Chapter 28: Clinical Pharmacology, Adverse Drug Reactions & Specific Poisonings

28.1 Pharmacokinetic Principles, Dose Adjustment & Drug Interactions in Critical Illness 28.2 Adverse Drug Reactions: Anaphylaxis, Severe Cutaneous Reactions & Hyperthermic Syndromes 28.3 Specific Poisonings: Sodium-Channel Blockers, Lithium, Valproate, Theophylline, Iron, Sulfonylureas & Methemoglobinemia

29 Chapter 29: Ethics, Research Methods, Administration & Abdominal Ultrasound

29.1 Advance Care Planning, Nonbeneficial Treatment, Informed Consent & Confidentiality 29.2 Critical Care Research Methods, Statistics, IRB Oversight & Quality Improvement 29.3 Abdominal, Vascular & Procedural Point-of-Care Ultrasound

10.3 Pituitary Emergencies, Adrenal Excess & Critical Illness-Related Corticosteroid Insufficiency

Key Takeaways Explain This Topic AI

Pituitary apoplexy is treated with immediate stress-dose hydrocortisone, because corticotropin deficiency and adrenal crisis cause the early deaths.

Central diabetes insipidus produces dilute urine (osmolality below about 300 mOsm/kg) with rising serum sodium; desmopressin concentrates the urine, whereas nephrogenic diabetes insipidus does not respond.

Severe endogenous hypercortisolism from ectopic ACTH causes hypokalemic metabolic alkalosis, hyperglycemia, and opportunistic infection, and is blocked with etomidate, metyrapone, ketoconazole, or osilodrostat.

CIRCI is a clinical diagnosis; a random cortisol or cosyntropin stimulation test does not reliably identify who benefits from corticosteroids in septic shock.

Postpartum pituitary infarction (Sheehan syndrome) typically presents with failure of lactation, hypoglycemia, and hyponatremia rather than the hypokalemia seen in primary adrenal failure.

Last updated: October 2026

Pituitary Apoplexy

Pituitary apoplexy is hemorrhage or infarction of the pituitary gland, almost always within an undiagnosed adenoma.

Triggers : anticoagulation, cardiac surgery with bypass, major hemodynamic swings, dynamic pituitary testing, dopamine agonists, pregnancy, and head trauma. Many cases are spontaneous.

Presentation :

Sudden severe headache (often retro-orbital or thunderclap).

Visual loss or bitemporal hemianopsia from chiasmal compression.

Ophthalmoplegia from cavernous sinus involvement, most often cranial nerve III (ptosis, a dilated pupil, and diplopia).

Nausea and vomiting, meningismus, and altered consciousness.

Hypotension, hyponatremia, and hypoglycemia from acute corticotropin deficiency.

Mimics : subarachnoid hemorrhage (CT may show only a sellar lesion, so look specifically at the sella), bacterial meningitis, and cavernous sinus thrombosis.

Imaging : pituitary MRI is the test of choice; CT often misses the hemorrhage.

Management :

Give hydrocortisone immediately (100 mg IV, then 50 mg every 6 hours or an infusion) before any confirmatory testing. Draw a cortisol first only if it does not cause delay.

Resuscitate with isotonic fluid and correct glucose and sodium.

Obtain urgent neurosurgical and ophthalmologic evaluation. Transsphenoidal decompression is indicated for severe or progressive visual loss or reduced consciousness; stable patients without visual compromise are often managed conservatively.

Replace other hormones later: thyroid hormone only after glucocorticoid replacement, because levothyroxine first can precipitate adrenal crisis.

Sheehan syndrome is postpartum pituitary infarction after obstetric hemorrhage. The acute form presents with hypotension, hypoglycemia, and hyponatremia; the chronic form presents with failure of lactation, amenorrhea, and fatigue. Unlike primary adrenal failure, potassium is normal or low because aldosterone, which is regulated by renin and potassium, is preserved, and hyperpigmentation is absent.

Central Diabetes Insipidus (Arginine Vasopressin Deficiency)

ICU settings : transsphenoidal surgery, traumatic brain injury, subarachnoid hemorrhage, hypoxic injury, and progression to brain death , where loss of posterior pituitary function causes massive polyuria.

Diagnosis : urine output above about 3 mL/kg/h with urine osmolality below about 300 mOsm/kg (specific gravity below 1.005) and a rising serum sodium and osmolality. Exclude osmotic diuresis from mannitol, hyperglycemia, contrast, and resolving acute kidney injury, and exclude excessive free water administration.

Confirm the type : desmopressin concentrates the urine in central diabetes insipidus and has little effect in the nephrogenic form (lithium, hypercalcemia, hypokalemia, tubular disease).

Management :

Desmopressin 1 to 2 micrograms IV or SC, repeated by response, or an infusion of arginine vasopressin in unstable patients and organ donors.

Replace the free water deficit and ongoing losses with hypotonic fluid (dextrose 5% or 0.45% saline), correcting chronic hypernatremia by no more than about 10 to 12 mEq/L in 24 hours.

Track hourly urine output, sodium every 2 to 4 hours during active treatment, and watch for the triphasic response after pituitary surgery: early diabetes insipidus, then a SIADH phase around days 5 to 10 (where continued desmopressin causes dangerous hyponatremia), then permanent diabetes insipidus.

In the organ donor , desmopressin or vasopressin plus careful sodium control protects kidney and liver grafts.

Adrenal Excess in the ICU

Severe endogenous hypercortisolism, usually from ectopic ACTH (small cell lung cancer, bronchial or thymic carcinoid, medullary thyroid cancer) or adrenocortical carcinoma, is a critical care problem in its own right:

Metabolic signature : hypokalemic metabolic alkalosis (cortisol saturates 11-beta-hydroxysteroid dehydrogenase type 2 and acts on mineralocorticoid receptors), severe hyperglycemia, hypertension, and proximal myopathy.

Complications : opportunistic infection ( Pneumocystis , invasive fungal disease), venous thromboembolism, psychosis, fractures, and poor wound healing.

Clues to ectopic ACTH over Cushing disease: rapid onset with little typical body habitus change, marked hypokalemia, very high ACTH and cortisol, and hyperpigmentation.

Management :

Block steroidogenesis: metyrapone , ketoconazole , osilodrostat , or etomidate by infusion in the ICU when oral therapy is not possible (etomidate inhibits 11-beta-hydroxylase at sub-hypnotic doses, with intensive monitoring).

Mifepristone blocks the receptor but cannot be monitored with cortisol levels.

Replace potassium and add spironolactone or eplerenone.

Give Pneumocystis prophylaxis and thromboprophylaxis.

Treat the tumor; bilateral adrenalectomy is a rescue for uncontrollable hypercortisolism.

Anticipate relative adrenal insufficiency after cortisol is suddenly normalized ("steroid withdrawal") and replace hydrocortisone.

Exogenous steroid excess matters too: patients on long-term glucocorticoids (prednisone above about 5 mg daily for more than 3 weeks) have suppressed adrenal axes and need stress dosing. Note that hydrocortisone and prednisolone cross-react with cortisol immunoassays, whereas dexamethasone does not , which is why dexamethasone is used when testing is planned.

Critical Illness-Related Corticosteroid Insufficiency (CIRCI)

CIRCI is inadequate glucocorticoid activity for the severity of illness , caused by impaired cortisol production, reduced cortisol metabolism, tissue resistance, and low cortisol-binding proteins. It is suspected in:

Vasopressor-dependent shock.

Persistent hypoglycemia, hyponatremia, or eosinophilia.

Unexplained fever and ongoing inflammation.

Testing limitations : total cortisol is misleading when albumin is low, because most cortisol is protein-bound; a delta cortisol after 250 micrograms of cosyntropin below 9 micrograms/dL and a random cortisol below 10 micrograms/dL were proposed criteria, but neither reliably predicts who benefits from steroids. Consensus guidelines and the Surviving Sepsis Campaign therefore treat clinically , without routine ACTH stimulation testing.

Where steroids have evidence in critical illness :

Septic shock : hydrocortisone 200 mg/day (50 mg every 6 hours or an infusion), suggested by the 2026 Surviving Sepsis Campaign. APROCCHSS added fludrocortisone and showed a mortality benefit; ADRENAL showed faster shock reversal without a mortality difference.

Severe community-acquired pneumonia without shock or influenza: hydrocortisone reduced mortality in CAPE COD.

Moderate-to-severe ARDS : dexamethasone reduced ventilator days and mortality in the DEXA-ARDS trial; corticosteroids are suggested with caution.

COVID-19 requiring oxygen : dexamethasone 6 mg daily (RECOVERY).

Acute adrenal crisis : hydrocortisone 100 mg IV then 200 mg/day, with isotonic fluid and dextrose.

Do not give steroids reflexively for undifferentiated hypotension without a plausible indication: hyperglycemia, ICU-acquired weakness, delirium, and immune suppression are real costs.