Adrenal insufficiency and adrenal crisis — branching viva

Branch 1 — The pigmented adolescent in shock

The candidate is expected to recognise primary adrenal insufficiency from the hyperpigmentation, the postural hypotension, the weight loss and the hyponatraemia with hyperkalaemia, and to lead with empiric hydrocortisone and fluids before any confirmatory test. The examiner probes the cortisol-ACTH-renin interpretation and the dose of parenteral hydrocortisone. [4]

Key teaching points the candidate must land: the high ACTH and high renin with low aldosterone localise the break to the adrenal cortex; the hyperpigmentation is driven by ACTH-driven melanocyte-stimulating POMC fragments; the dose is 50 to 100 mg of intravenous hydrocortisone for an adolescent, then 50 to 100 mg per square metre per 24 hours; and sepsis is covered in parallel because it coexists and is indistinguishable. [1]

Branch 2 — The steroid-withdrawn asthmatic boy

The candidate must distinguish glucocorticoid-induced secondary insufficiency from primary disease: the potassium is normal, the child is pale, and the history of recent steroid withdrawal is the clue. The examiner probes why aldosterone and pigmentation are spared and why the axis may not recover for months. [6]

The mechanism to explain is that aldosterone is governed by the renin-angiotensin system rather than by ACTH, so it survives the loss of trophic drive and the potassium stays normal; ACTH is low rather than high, so there is no melanocyte stimulation and no pigmentation. The resuscitation is identical to primary crisis — fluids, parenteral hydrocortisone and glucose — and the medium-term plan is a slow wean over months. [6]

Branch 3 — The known adrenal child who is vomiting

The candidate must convert a known treated child into an emergency: vomiting in a child on hydrocortisone means oral replacement cannot be absorbed, so the family gives the parent-held intramuscular hydrocortisone and presents immediately. The examiner probes the stress-dose principle and the emergency-kit doses. [1]

The doses to give without hesitation are the emergency intramuscular hydrocortisone — infant 25 mg, child 50 mg, adolescent 100 mg — and the doubled or tripled oral hydrocortisone for any febrile illness in a child who is not vomiting. The candidate should teach the family to inject first and call for help second, because the hours of delay in a vomiting child are the gap in which crisis deaths happen. [3]

Closing — the lifelong plan and the preventable death

The examiner closes on prognosis and prevention: with early diagnosis, disciplined replacement and a working stress-dose plan, intellectual development and lifespan are near-normal, and the modifiable factor is whether the diagnosis and emergency plan are built before a crisis. The candidate names the preventable death — the missed crisis treated as gastroenteritis or sepsis while the adrenal fails — and the countermeasure: a low threshold for one dose of empiric intravenous hydrocortisone. [3]