Makindo Medical Notes

Related Subjects: | Prolactin | Prolactinoma | Sheehan's Syndrome

📖 About

• Sheehan's syndrome is a rare but important cause of hypopituitarism 👩‍🍼, resulting from ischaemic necrosis of the pituitary gland after severe postpartum haemorrhage.
• It differs from pituitary apoplexy, which is usually due to haemorrhage into a pituitary adenoma 🧠.
• Symptoms may present acutely (e.g. failure to lactate, amenorrhoea) or insidiously over years, making diagnosis delayed ⏳.
• Classic early clues: agalactia (failure to breastfeed) and secondary amenorrhoea soon after delivery.

🩸 Aetiology & Pathophysiology

• During pregnancy, the anterior pituitary enlarges (driven by lactotroph hyperplasia) but its blood supply does not increase proportionally ➝ vulnerable to hypoperfusion.
• Severe postpartum haemorrhage with hypovolaemia and hypotension leads to infarction of the anterior pituitary.
• Posterior lobe involvement is uncommon but may lead to diabetes insipidus 🚰.

🩺 Clinical Features

• Early: Failure to lactate (low prolactin), persistent amenorrhoea.
• Chronic: Fatigue, hypotension, weight loss, loss of libido, infertility.
• Adrenal insufficiency ➝ loss of pubic/axillary hair, hypotension.
• Thyroid axis deficiency ➝ cold intolerance, dry skin, bradycardia.
• Posterior pituitary involvement (rare): polyuria, polydipsia (diabetes insipidus).
• Up to 70% of anterior pituitary tissue may be destroyed before overt symptoms appear ⚠️.

🔬 Investigations

• Hormonal profile: ↓ TSH, ↓ Prolactin (unique), ↓ LH/FSH, ↓ GH, ↓ Cortisol (secondary adrenal insufficiency).
• MRI pituitary: empty sella or atrophic pituitary.
• Dynamic pituitary function tests can assess reserve (e.g. insulin tolerance test).
• Thyroid and adrenal tests confirm secondary endocrine deficiencies.

💊 Management

• Hormone replacement therapy tailored to deficits:
  • Hydrocortisone for adrenal insufficiency (replace steroids before thyroid hormone!)
  • Levothyroxine for hypothyroidism
  • Sex steroid replacement (oestrogen/progesterone or testosterone) for hypogonadism
  • Growth hormone in selected patients
• 💧 Desmopressin if diabetes insipidus is present.
• Ongoing follow-up with endocrine review; doses need to be adjusted in stress/illness.
• Education on “sick day rules” and the need to carry a steroid emergency card 💳.

📚 Key Points for Exams

• Postpartum woman + failure to lactate + amenorrhoea = think Sheehan’s 🧩.
• Low prolactin is highly suggestive (rare in other hypopituitarism).
• Differentiate from pituitary apoplexy (usually sudden headache, visual loss, adenoma background).

🔗 References

• StatPearls: Sheehan Syndrome
• Journal of Clinical Endocrinology & Metabolism – Clinical Review