ACTH Deficiency: Symptoms, Adrenal Crisis Risk, and Urgent Care

Secondary Adrenal Insufficiency from ACTH Deficiency

ACTH (adrenocorticotropic hormone) from anterior pituitary drives cortisol production. Deficiency → hypocortisolism without mineralocorticoid loss (aldosterone RAAS-regulated).

Chronic Symptoms (Insidious)

• Fatigue, weakness, weight loss, anorexia.
• Hypotension (orthostatic), nausea, vomiting, diarrhea.
• Hypoglycemia (fasting), hyponatremia (SIADH-like).
• Loss of axillary/pubic hair (androgen deficiency — women).
• Menstrual irregularities, infertility.
• Hyperpigmentation absent (vs. primary Addison's) — ACTH low → no MSH co-secretion.

Adrenal Crisis (Medical Emergency)

• Precipitants: stress (infection, surgery, trauma), abrupt steroid withdrawal.
• Sudden hypotension, shock, altered mental status, severe abdominal pain, fever.
• Labs: hypoglycemia, hyponatremia, hyperkalemia (mild), metabolic acidosis.

Immediate Treatment

1. Hydrocortisone 100 mg IV bolus → then 200 mg/24 hr continuous infusion or 50 mg IV q6h.
2. Aggressive IV fluids (NS 1–2 L bolus).
3. Dextrose if hypoglycemic.
4. Treat underlying trigger (antibiotics, etc.).
5. Transition to oral hydrocortisone 15–25 mg/day (divided) + fludrocortisone not needed (aldosterone intact).

Etiologies

• Pituitary adenoma/surgery/radiation.
• Sheehan's syndrome (postpartum pituitary necrosis).
• Traumatic brain injury.
• Autoimmune hypophysitis (checkpoint inhibitors).
• Infiltrative (hemochromatosis, sarcoid, metastases).

Wear medical alert; carry emergency injection kit (hydrocortisone 100 mg IM). Stress-dose steroids for illness/surgery.