Adrenal Disorders — Written Clinical Reasoning

SAQ 1 — Adrenal Crisis: Emergency Management and Diagnostic Reasoning (20 marks, 30 minutes)

Prompt: This patient is in adrenal crisis. Outline your immediate emergency management (with drug doses and route), the diagnostic reasoning that confirms primary adrenal insufficiency, and the long-term management and patient education plan. Justify each decision with reference to the Endocrine Society guideline. ^[1]

Model Answer

Step 1 — Immediate emergency management (the first 30 minutes) (6 marks): ^[1]

This is a life-threatening adrenal crisis. I do NOT delay treatment for further tests — the mortality of untreated crisis is significant. My immediate actions: ^[1]

1. Secure the airway and give high-flow oxygen (she is drowsy and hypoxic risk). Establish IV access (two large-bore cannulae).
2. Take blood FIRST (within 1-2 minutes, before hydrocortisone if possible, but do NOT delay hydrocortisone beyond this): cortisol (already low at 45 — confirms), ACTH (already high at 520 — confirms primary), renin, aldosterone, electrolytes, glucose (already low at 2.1), FBC, blood cultures. The cortisol and ACTH results are already available and are diagnostic.
3. IV hydrocortisone 100 mg stat, then 100 mg every 6-8 hours (or a continuous infusion of 200 mg over 24 hours). At these doses hydrocortisone provides sufficient mineralocorticoid activity — fludrocortisone is not needed acutely. The Bornstein 2016 Endocrine Society guideline (PMID 26760044) is explicit: treat first if the patient is sick.
4. Aggressive IV fluid resuscitation: 1 litre of 0.9% saline stat, then 1 litre over 1 hour, then guided by clinical response. Add dextrose (e.g. 1 litre of 5% dextrose alternating with saline) — she is hypoglycaemic at 2.1 mmol/L, which is dangerous. Treat the hypoglycaemia directly: 50 mL of 50% dextrose IV (or 100 mL of 10% dextrose if central access is unavailable).
5. Correct electrolytes: The hyperkalaemia (6.4) is from aldosterone deficiency and will resolve with hydrocortisone and fluids over the next few hours. I do NOT give insulin-dextrose or calcium resonium routinely unless there are ECG changes of severe hyperkalaemia (wide QRS) — those would be treated with the standard hyperkalaemia protocol. Check an ECG now.
6. Identify and treat the precipitant: Blood and urine cultures, chest X-ray. Start broad-spectrum antibiotics (e.g. ceftriaxone 2g IV) once cultures are taken — she is febrile (38.5) and infection (likely gastroenteritis) is the commonest precipitant. ^[1]

Step 2 — Diagnostic reasoning — why this is primary adrenal insufficiency (3 marks): ^[1]

The diagnosis is confirmed by:

• Cortisol 45 nmol/L (markedly low — a stressed patient should have cortisol above 500 nmol/L; a value below 200 in an unwell patient is strongly suggestive of adrenal insufficiency).
• ACTH 520 pg/mL (markedly elevated, over 8 times the upper limit) — this is the key finding: the ACTH is HIGH, confirming the problem is at the ADRENAL level (primary). In secondary adrenal insufficiency (pituitary), ACTH would be low or inappropriately normal.
• Hyperpigmentation (palmar creases, buccal mucosa, scars) — pathognomonic: high ACTH/MSH cross-stimulates melanocytes. This is ABSENT in secondary adrenal insufficiency.
• Hyponatraemia (119) with hyperkalaemia (6.4) — the hallmark of aldosterone deficiency (primary). In secondary, the RAAS is intact, aldosterone is preserved, and potassium is NORMAL. This is the single best biochemical discriminator.
• Hypoglycaemia — cortisol is needed for gluconeogenesis; deficiency causes fasting hypoglycaemia.
• Autoimmune context (type 1 diabetes, autoimmune thyroid disease) — this is autoimmune polyglandular syndrome type 2 (Schmidt syndrome), the commonest cause of Addison's in developed countries. ^[1]

The short Synacthen test (250 mcg cosyntropin, cortisol at 0, 30, 60 min) would confirm a peak cortisol below 500 nmol/L, but in this acute setting it is unnecessary — the cortisol is already critically low with a high ACTH, and treatment should not wait. The Synacthen test can be done after recovery to document the baseline deficit formally. ^[1]

Step 3 — Finding the cause (2 marks): ^[1]

After stabilisation:

• 21-hydroxylase antibodies — to confirm autoimmune Addison's (positive in 80-90% of autoimmune cases). This is the expected cause given her autoimmune history.
• Adrenal CT — small/atrophic adrenals confirm autoimmune disease; enlarged adrenals suggest infiltrative/malignant causes; calcified adrenals suggest old TB.
• Screen for and manage associated autoimmune conditions (thyroid, B12/pernicious anaemia, premature ovarian failure) — she already has type 1 diabetes and thyroid disease. ^[1]

Step 4 — Long-term replacement therapy (4 marks): ^[1]

Once stable and able to take oral medications:

• Hydrocortisone 15-25 mg/day in divided doses — e.g. 10 mg on waking, 5 mg at midday, 5 mg at 4-5 pm. The largest dose is in the morning (mimicking the circadian peak); the smallest dose is latest (to avoid insomnia). Titrate to well-being, with a day curve (serial cortisol measurements through the day) if symptoms persist.
• Fludrocortisone 50-200 mcg/day (typically 100 mcg) — ESSENTIAL in primary adrenal insufficiency, because the adrenal cannot produce aldosterone. Monitor with blood pressure (including postural), serum sodium, and plasma renin (aim for high-normal renin).
• Continue treatment for any precipitating cause (e.g. infection).
• Address bone health (DEXA — she is at risk of osteoporosis from chronic illness, not from the hydrocortisone replacement at physiological doses, but she may have other risk factors). ^[1]

Step 5 — Patient education and prevention of future crises (3 marks): ^[1]

This is the most important long-term intervention. Hahner et al. (PMID 25419882) showed that adrenal crises still occur in 8.3 per 100 patient-years in EDUCATED patients, with a 6% mortality per crisis — so education must be comprehensive and reinforced:

• Sick-day rules: double oral hydrocortisone for minor illness (fever, infection); triple or give IM hydrocortisone 100 mg for severe illness, vomiting, or surgery. Provide WRITTEN instructions.
• Emergency hydrocortisone injection kit (100 mg vial, syringes, instructions) — teach the patient and at least one family member to give IM hydrocortisone. She carries this at all times.
• MedicAlert bracelet stating "Adrenal insufficiency — requires hydrocortisone."
• Steroid card with diagnosis, medications, and emergency instructions.
• Education on never omitting steroids, recognizing early crisis symptoms (nausea, vomiting, weakness, dizziness), and when to seek urgent medical attention. ^[1]

Step 6 — Communication and shared decision-making (2 marks):

• Explain the diagnosis in plain language: "Your adrenal glands, which sit above your kidneys, have been destroyed by your immune system. They cannot make the hormones you need to stay alive — cortisol and aldosterone. We will replace these hormones for life."
• Discuss the autoimmune context and screen family members if there is a family history of autoimmune endocrinopathy.
• Address the psychological impact of a lifelong diagnosis requiring daily medication and emergency preparedness. ^[1]