MBBS SAQ · Endocrinology / General Medicine
Hypopituitarism — adrenal crisis, the hydrocortisone-first rule and Sheehan syndrome
A final-prof / NEET-PG SAQ on Sheehan syndrome presenting as secondary adrenal crisis — recognition of the postpartum triad, distinguishing secondary from primary adrenal insufficiency (no hyperkalaemia, no pigmentation, aldosterone spared), the hydrocortisone-before-levothyroxine rule, the investigation pattern (low target hormone with low trophic hormone, free T4 monitoring, pituitary MRI), and lifelong replacement with sick-day education.
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Question
A 34-year-old woman is brought to the emergency department 10 weeks after a complicated home delivery complicated by severe postpartum haemorrhage requiring transfusion. She reports she has been unable to breastfeed, has not resumed menstruation, and over two days has become increasingly drowsy with vomiting. On examination she is pale, has lost her axillary and pubic hair, blood pressure is 88/52 mmHg, and there is no pigmentation. Sodium is 124 mmol/L, potassium 4.0 mmol/L, glucose 2.6 mmol/L, and a random cortisol is low with a low ACTH. Outline the diagnosis, the immediate management, the investigation strategy, and the long-term plan with sick-day education.[1][2]
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Diagnosis: Sheehan syndrome (postpartum pituitary necrosis) presenting as secondary adrenal crisis. The agalactia, persistent amenorrhoea and hypopituitarism following severe postpartum haemorrhage form the classic Sheehan triad; the low cortisol with a low ACTH and the hyponatraemia, hypoglycaemia and hypotension indicate an acute adrenal crisis. Critically there is no hyperpigmentation and a normal potassium (4.0 mmol/L) — because aldosterone is driven by the renin-angiotensin system, not ACTH, and is therefore spared. This is secondary (pituitary) adrenal insufficiency, not primary Addison disease.[1][2]
Immediate management — treat the adrenal crisis, do not wait for further results.[2][3]
- ABCDE: secure airway; high-flow oxygen; two large-bore cannulae.
- IV hydrocortisone 100 mg stat, then 50 mg IV every 6 hours (or 200 mg per 24 hours as an infusion).[3]
- Aggressive 0.9% sodium chloride resuscitation guided by haemodynamic response; correct hypoglycaemia with IV dextrose.
- Identify and treat any precipitant (infection); monitor electrolytes and glucose.
- Fludrocortisone is NOT needed (aldosterone/RAAS intact). Hold levothyroxine until the cortisol axis is covered.
The cardinal rule — glucocorticoid before thyroid hormone.[1]
- Always replace hydrocortisone BEFORE levothyroxine. Levothyroxine increases metabolic demand and cortisol clearance; giving it alone in uncorrected ACTH deficiency precipitates a fatal adrenal crisis. Start levothyroxine only after hydrocortisone is established.
- The defining pattern is a low target hormone with a low or inappropriately normal trophic hormone — low cortisol with low ACTH; low free T4 with low TSH; low oestradiol with low LH/FSH; low IGF-1; prolactin classically low in Sheehan.
- A basal 8–9 am cortisol under 3 µg/dL (about 80 nmol/L), confirmed on repeat and paired with a low or normal ACTH, is highly suggestive of secondary adrenal insufficiency; over 15 µg/dL (about 400 nmol/L) virtually excludes it. In equivocal early cases (under 2–4 weeks of ACTH deficiency) use the insulin tolerance test (the short Synacthen test is falsely normal before the adrenal atrophies).[2]
- Pituitary MRI confirms the cause (partial empty sella or infarcted gland in Sheehan) and excludes an adenoma/apoplexy; formal visual-field perimetry if any mass effect.
Long-term plan and sick-day education.[1][3]
- Hydrocortisone 15 to 25 mg/day in divided doses (for example 10 mg on waking, 5 mg midday, 5 mg early evening), titrated clinically.[3]
- Levothyroxine about 1.6 mcg/kg/day, monitored by free T4, not TSH.
- Sex-steroid replacement (oestrogen-progestogen HRT for this premenopausal woman); GH replacement if proven deficient; desmopressin only if diabetes insipidus develops.
- Sick-day rules: double the oral hydrocortisone for moderate illness; triple or switch to IM/IV for severe illness, vomiting or surgery; carry an emergency hydrocortisone 100 mg IM/SC injection kit; wear a steroid emergency card and MedicAlert bracelet; never stop steroids.
- Lifelong endocrinology follow-up, reproductive counselling for fertility, and prevention of future Sheehan with adequate obstetric care.
Common errors
- Mistaking this for primary Addison disease — Addison has hyperpigmentation, hyperkalaemia and salt-wasting, and needs fludrocortisone; secondary (pituitary) disease has none of these.[1]
- Giving levothyroxine before hydrocortisone — precipitates adrenal crisis; always glucocorticoid first.[3]
- Monitoring levothyroxine with TSH — in hypopituitarism TSH is unreliable; use free T4.[1]
- Using fludrocortisone — unnecessary, because aldosterone is driven by RAAS and is intact.[2]
- Relying on a short Synacthen test early — it can be falsely normal before adrenal atrophy; use an insulin tolerance test if in doubt.[2]
- Forgetting sick-day and emergency-injection education — the preventable cause of recurrent adrenal crisis and excess mortality.[3]
Examiner notes
- The exam wants a structured answer: recognise Sheehan syndrome from the postpartum triad, state the secondary adrenal crisis with the no-hyperkalaemia/no-pigmentation discriminator, then the emergency hydrocortisone bundle with doses, the hydrocortisone-before-levothyroxine rule, the investigation pattern (low target with low trophic hormone; free T4 monitoring; MRI), and lifelong replacement with sick-day education.[1][2]
- Full marks require stating that aldosterone is spared (RAAS intact) and that fludrocortisone is not needed.
- A strong candidate mentions MedicAlert identification, the emergency injection kit, and the Endocrine Society 2016 guideline.[3]
References3ShowHide
- [1]Yeliosof O, Gangat M. Diagnosis and management of hypopituitarism. Current Opinion in Pediatrics, 2019.PMID 31082937
- [2]Iglesias P. An Update on Advances in Hypopituitarism: Etiology, Diagnosis, and Current Management. Journal of Clinical Medicine, 2024.PMID 39458112
- [3]Fleseriu M, Hashim IA, Karavitaki N, et al. Hormonal Replacement in Hypopituitarism in Adults: An Endocrine Society Clinical Practice Guideline. Journal of Clinical Endocrinology and Metabolism, 2016.PMID 27736313