Addison's disease
Failure of the adrenal cortex to produce cortisol and aldosterone. Slow-burning fatigue, hyperpigmentation, salt craving and low blood pressure — but acutely it can present as a life-threatening adrenal crisis with shock and hyperkalaemia.
What it is
Addison's disease is primary adrenal insufficiency — destruction of the adrenal cortex itself, with loss of both glucocorticoid (cortisol) and mineralocorticoid (aldosterone) production. In high-income countries the leading cause is autoimmune adrenalitis (frequently part of autoimmune polyglandular syndrome with autoimmune thyroid disease, type 1 diabetes, vitiligo). Globally, tuberculosis remains a major cause; less commonly the adrenals are destroyed by metastases, haemorrhage, infection (HIV-associated), infiltrative disorders or genetic conditions (adrenoleukodystrophy, congenital adrenal hyperplasia). Symptoms develop insidiously over months — fatigue, anorexia, weight loss, nausea, postural light-headedness, salt craving, and characteristic skin and oral-mucosa hyperpigmentation (driven by high ACTH stimulating melanocortin receptors). Stress (infection, surgery, trauma) can precipitate an adrenal crisis — hypotension, vomiting, hyperkalaemia, hyponatraemia, hypoglycaemia — which is a medical emergency.
Key lab markers
- Sodium — low (aldosterone deficiency → renal sodium loss).
- Potassium — high (aldosterone deficiency → renal potassium retention).
- Morning cortisol — low (<5 µg/dL highly suggestive; <3 nearly diagnostic).
- ACTH — high (loss of negative feedback).
- Aldosterone — low with high renin.
- Fasting glucose — often low (cortisol counters insulin).
- CBC — mild normocytic anaemia, eosinophilia, lymphocytosis.
- Anti-adrenal (21-hydroxylase) antibodies — positive in autoimmune form.
- ACTH stimulation test — gold standard (cortisol fails to rise after synthetic ACTH).
Symptoms
- Profound fatigue, malaise
- Unintentional weight loss with anorexia, nausea, vomiting, abdominal pain
- Hyperpigmentation — palmar creases, knuckles, scars, oral mucosa (the diagnostic hallmark)
- Postural dizziness, low blood pressure
- Salt craving
- Decreased libido, irregular periods
- Acute crisis: severe hypotension/shock, confusion, vomiting, severe hyperkalaemia
When to discuss with a doctor
Unexplained chronic fatigue with weight loss, low blood pressure, salt craving and hyperpigmentation requires prompt morning cortisol + ACTH + electrolytes. A 9 a.m. cortisol below 5 µg/dL or hyponatraemia + hyperkalaemia without another explanation triggers urgent endocrinology referral. Anyone confirmed must be educated about stress-dose hydrocortisone, must wear medical-alert identification, and carry an emergency hydrocortisone injection. Mediora.AI flags the suggestive Na-K pattern; an adrenal crisis is a 999/911 emergency.