Can a malignant pituitary infarction (pituitary apoplexy or Sheehan's syndrome) cause secondary adrenal insufficiency?

Pituitary Infarction and Secondary Adrenal Insufficiency

Yes, pituitary infarction (pituitary apoplexy or Sheehan's syndrome) directly causes secondary adrenal insufficiency by destroying ACTH-producing cells, resulting in life-threatening cortisol deficiency that requires immediate glucocorticoid replacement. 1, 2, 3

Mechanism of Adrenal Insufficiency

Pituitary apoplexy causes secondary adrenal insufficiency through acute destruction of corticotroph cells:

• Hemorrhage or infarction of the pituitary gland destroys ACTH-producing cells, eliminating the signal to the adrenal glands to produce cortisol 1, 3
• The resulting ACTH deficiency leads to low cortisol levels with inappropriately low or normal ACTH—the hallmark of secondary adrenal insufficiency 4
• Corticotropic axis involvement may result in severe hypotension and impaired consciousness, making this a medical emergency 1, 3

Clinical Presentations

Pituitary apoplexy presents with sudden-onset severe headache, visual disturbances, and acute adrenal crisis 1, 3. The corticotropic deficiency can be life-threatening if untreated 3.

Sheehan's syndrome (postpartum pituitary necrosis) occurs after severe postpartum hemorrhage and hypovolemic shock 2, 5. It causes varying degrees of anterior pituitary dysfunction, with ACTH deficiency being one of the most critical hormone losses 2. While some cases present acutely with failure to lactate and adrenal crisis 5, 6, many women remain undiagnosed for years after delivery 2.

Immediate Management Algorithm

For suspected pituitary apoplexy with adrenal insufficiency:

1. Administer hydrocortisone 100 mg IV immediately before any diagnostic testing 4
2. Begin aggressive isotonic saline resuscitation (≥2 L rapidly, then ≥1 L/hour) 4
3. Continue hydrocortisone 200 mg/24 h by continuous infusion until oral intake is possible 7, 4
4. If diagnosis is uncertain and cortisol testing is needed, use dexamethasone 4 mg IV instead (does not interfere with cortisol assays) 4

Critical Pitfall to Avoid

Never delay glucocorticoid administration while awaiting diagnostic confirmation. 7, 4 If there is any suspicion of pituitary apoplexy or Sheehan's syndrome, administer stress-dose steroids immediately—short-term glucocorticoid exposure carries minimal risk, but untreated adrenal crisis is fatal 7, 4. The majority of patients (70%) with pituitary apoplexy require surgery, but all require immediate glucocorticoid coverage regardless of surgical plans 1.

Long-Term Considerations

After stabilization, patients require:

• Lifelong hydrocortisone replacement (15-25 mg daily in divided doses, typically 10-20 mg on waking, 5-10 mg early afternoon) 4
• If central hypothyroidism coexists, start glucocorticoid replacement several days before levothyroxine to avoid precipitating adrenal crisis 4
• Medical alert bracelet stating "adrenal insufficiency" 4
• Emergency injection kit (hydrocortisone 100 mg IM) with training for patient and caregivers 4
• Stress-dosing protocols: double or triple usual dose during illness; for surgery, give hydrocortisone 100 mg IV at induction followed by 200 mg/24 h infusion 7, 4