Hypoadrenocorticism, or Addison's disease, is a deficiency of adrenal cortical hormones (glucocorticoids and usually mineralocorticoids). Signs are often vague and waxing-waning, but the disease can present dramatically as an adrenal crisis with collapse and shock. It is treatable with lifelong hormone supplementation and carries a good prognosis once stabilized.
Addison's disease is an uncommon but important endocrine disorder in dogs, typically affecting young to middle-aged females. It is sometimes called the great pretender because its signs mimic many other illnesses.
Most cases result from immune-mediated destruction of the adrenal cortex, reducing production of cortisol and aldosterone. It can also follow abrupt withdrawal of long-term steroids or damage from other adrenal disease.
Dogs show intermittent lethargy, poor appetite, vomiting, diarrhoea, and weakness. Crisis presents as collapse, dehydration, and shock, often with low sodium and high potassium causing heart rhythm disturbances.
Suggestive bloodwork includes electrolyte imbalances and azotaemia. Definitive diagnosis uses an ACTH stimulation test showing minimal cortisol response.
Acute crisis requires intravenous fluids and steroids. Long-term management uses injectable or oral mineralocorticoid (such as DOCP) plus glucocorticoid replacement, with periodic electrolyte monitoring.
There is no prevention, but recognising early signs and avoiding sudden steroid withdrawal reduces crises. Lifelong therapy gives most dogs a normal lifespan.
This content is for educational purposes and is not a substitute for professional veterinary advice. If you are worried about your pet, contact your veterinarian.
