4.6 Adrenal Crisis and Incretin/Endocrine Emergencies

4.6 Adrenal Crisis and Incretin/Endocrine Emergencies

Endocrine emergencies require rapid recognition and highly structured resuscitation. Flight teams must manage hormonal deficits and severe metabolic derangements while maintaining hemodynamic stability during transport.

Adrenal Crisis (Acute Adrenal Insufficiency)

Cortisol is the primary glucocorticoid, responsible for maintaining vascular sensitivity to catecholamines, stimulating gluconeogenesis, and downregulating the inflammatory response. Aldosterone is the primary mineralocorticoid, responsible for renal sodium conservation and potassium excretion.

Adrenal crisis occurs when there is an acute, life-threatening deficiency of cortisol and aldosterone, often triggered by severe physiological stressors (e.g., infection, trauma, surgery, burns) in a patient with Addison's disease or secondary adrenal insufficiency (e.g., chronic corticosteroid therapy with sudden withdrawal).

Clinical Presentation

• Distributive-type shock that is completely refractory to fluids and vasopressors.
• Severe hypoglycemia.
• Hyponatremia (due to lack of aldosterone causing renal sodium wasting).
• Hyperkalemia (due to potassium retention).

Transport Resuscitation

1. Fluid Management: Aggressive volume resuscitation with D5NS (5% Dextrose in 0.9% Normal Saline). The normal saline corrects the intravascular volume depletion and hyponatremia, while the 5% dextrose corrects the hypoglycemia.
2. Corticosteroid Replacement:
   • Dexamethasone: 4 mg IV bolus. Preferred if the diagnosis of adrenal insufficiency is not yet established, because it does not cross-react with serum cortisol assays, allowing diagnostic ACTH stimulation testing in the hospital.
   • Hydrocortisone: 100 mg IV bolus. Provides both glucocorticoid and mineralocorticoid activity. This is the drug of choice in transport if the diagnosis is established.
3. Vasopressors: Will be ineffective without corticosteroids. Cortisol is required to restore vascular responsiveness to catecholamines (the permissive effect on alpha-1 receptors).

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Hyperglycemic Crises: DKA vs. HHS

Resuscitation Guidelines

1. Fluid Resuscitation: The first priority. Administer 1–2 L of 0.9% Normal Saline (or 20 mL/kg in pediatrics). Rapid volume expansion reduces counter-regulatory hormones and lowers blood glucose.
2. Potassium Management: Insulin drives potassium into cells via the Na+/K+ ATPase pump. If the serum potassium is <3.3 mEq/L, insulin must be withheld and potassium repleted (20–40 mEq/hr) until the potassium level is >3.3 mEq/L. Starting insulin in a hypokalemic patient can trigger fatal ventricular dysrhythmias. If potassium is 3.3–5.3 mEq/L, add potassium (20–30 mEq/L) to IV fluids. If potassium is >5.3 mEq/L, do not add potassium, but monitor closely.
3. Insulin Infusion: Infuse regular insulin at 0.1 units/kg/hour (or 0.1 units/kg bolus followed by 0.1 units/kg/hour). Target rate of glucose decline is 75 to 100 mg/dL/hour. If glucose drops too rapidly, the sudden change in serum osmolality can cause water to shift into brain cells, leading to cerebral edema.
4. Transitioning Fluids: When the blood glucose falls to 250 mg/dL (DKA) or 300 mg/dL (HHS), transition IV fluids to a dextrose-containing fluid (e.g., D5 1/2 NS) to allow continued insulin infusion to clear ketones and close the anion gap while preventing hypoglycemia.

[!IMPORTANT] Pediatric DKA: High risk of cerebral edema, which is associated with high mortality. Minimize boluses unless in overt shock; rehydrate gradually over 36 to 48 hours. Monitor for signs of cerebral edema (bradycardia, pupillary changes, headache, deteriorating mental status), and treat immediately with Mannitol (0.5–1 g/kg IV over 20 mins) or 3% Hypertonic Saline (5–10 mL/kg over 30 mins).

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Thyroid Storm

A rare, life-threatening crisis of extreme thyrotoxicosis. Presentation: Hyperthermia (>40°C), tachycardia/arrhythmias (atrial fibrillation), high-output heart failure, agitation, delirium, and diarrhea.

Multimodal Treatment Sequence (Must be given in order)

1. Control Sympathetic Hyperactivity: Propranolol (1–2 mg IV slow push, or 60–80 mg PO every 4 hours). It blocks beta-adrenergic receptors and inhibits the peripheral conversion of thyroxine (T4) to the active triiodothyronine (T3).
2. Block New Hormone Synthesis: Propylthiouracil (PTU, 600–1000 mg PO/NG, then 200–250 mg every 4 hours) or Methimazole (20 mg PO/NG). PTU is preferred because it also blocks peripheral conversion of T4 to T3.
3. Block Hormone Release: Iodine therapy (Lugol's solution, 5–10 drops PO/NG every 8 hours, or Potassium Iodide). Critical sequence: Iodine must be administered at least 1 hour after PTU or Methimazole. If iodine is given first, the thyroid gland will use it as substrate to synthesize and release more thyroid hormone, worsening the storm (Wolff-Chaikoff effect or Jod-Basedow effect).
4. Block Peripheral Conversion & Treat Adrenal Insufficiency: Hydrocortisone (100 mg IV every 8 hours) or Dexamethasone (2–4 mg IV every 6 hours).
5. Supportive Care: Cool the patient actively. Avoid aspirin, which displaces thyroid hormone from thyroid-binding globulin, increasing free T4/T3 levels; use acetaminophen or physical cooling instead.

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GLP-1 Receptor Agonists and Transport Airway Management

Glucagon-like peptide-1 (GLP-1) receptor agonists (e.g., semaglutide, liraglutide, tirzepatide) delay gastric emptying. During rapid sequence intubation (RSI) in critical care transport, these patients must be treated as having a full stomach regardless of fasting status. High risk of silent regurgitation and severe aspiration pneumonitis. Transport crews should ensure suction is set up, use a rapid sequence intubation approach with optimal positioning (head-up or ramped), and consider gastric decompression with an orogastric/nasogastric tube after the airway is secured.