Primary adrenal insufficiency (Addison's disease) is failure of the adrenal cortex with loss of cortisol, aldosterone and adrenal androgens.
Adrenal crisis is an acute, life‑threatening deterioration in adrenal function causing hypotension/shock, severe electrolyte disturbance or hypoglycaemia and requires immediate treatment (NICE NG243).
Pathophysiology
Cortisol deficiency → weakness, anorexia, nausea/vomiting, abdominal pain and predisposition to hypoglycaemia; loss of negative feedback → raised ACTH in primary disease.
Aldosterone deficiency (primary only) → renal sodium loss, water loss, hyperkalaemia and hypotension.
Adrenal androgen loss is clinically relevant mainly in women.
Secondary/tertiary adrenal insufficiency (pituitary disease or long‑term steroid suppression) causes low cortisol with preserved aldosterone (so hyperkalaemia is uncommon).
Key biochemical disturbances
Hyponatraemia
Hyperkalaemia (primary disease)
Hypoglycaemia (particularly children)
Possible hypercalcaemia
Acute kidney injury and mild metabolic acidosis from volume depletion
Red‑flag features - when to suspect adrenal crisis in ED triage
Hypotension, collapse or persistent postural dizziness, especially if poorly responsive to usual resuscitation
Unexplained hyponatraemia ± hyperkalaemia
Severe or persistent nausea, vomiting or abdominal pain with systemic features (malaise, fever)
Hypoglycaemia, especially in children or when otherwise unexplained
Acute deterioration in a patient on long‑term glucocorticoids or after recent steroid withdrawal
Known adrenal insufficiency who cannot take oral steroids
Quick clinical distinction: primary vs secondary
Initial assessment and investigations (do not delay treatment)
Immediate:...
Ready to master this topic for the FRCEM?
Complete Management: Full NICE & RCEM-aligned algorithms.
SBA Practice: Topic-linked questions to test your knowledge.
Exam Analytics: Track your syllabus coverage in real-time.
