Addisonian Crisis in Dogs: Emergency Welfare Management
What Is an Addisonian Crisis?
An Addisonian crisis (acute hypoadrenocorticism) occurs when adrenal glands fail to produce adequate cortisol and/or aldosterone, causing cardiovascular collapse, severe electrolyte disturbances, and life-threatening shock. Dogs with undiagnosed Addison's disease or those whose medication has been missed or discontinued may present in crisis. It is most common in young to middle-aged female dogs; predisposed breeds include Standard Poodles, Portuguese Water Dogs, Nova Scotia Duck Tolling Retrievers, and Bearded Collies.
Clinical Emergency Presentation
Dogs in Addisonian crisis present with: profound weakness or collapse; bradycardia (slow heart rate from hyperkalaemia); hypotension (low blood pressure); hypothermia; vomiting; abdominal pain; and a history of waxing-waning illness. The combination of bradycardia with severe illness (many causes of shock cause tachycardia) is a classic clinical clue. Without treatment, death occurs rapidly from cardiac arrhythmia (hyperkalaemia causes characteristic ECG changes) and cardiovascular failure.
Emergency Treatment
Emergency treatment: IV access immediately; aggressive IV normal saline (0.9% NaCl) fluid therapy to restore intravascular volume and dilute potassium; ECG monitoring for hyperkalaemic arrhythmias; dexamethasone sodium phosphate IV (does not interfere with ACTH stimulation test if needed) to replace cortisol immediately; correction of hypoglycaemia if present; and monitoring of electrolytes (K+, Na+) to guide ongoing fluid therapy and mineralocorticoid replacement.
Diagnosis During Stabilisation
ACTH stimulation test (measures baseline and post-ACTH cortisol) confirms hypoadrenocorticism. Blood chemistry shows: hyperkalaemia; hyponatraemia; hypoglycaemia; azotaemia (pre-renal); and eosinophilia/lymphocytosis (absence of stress leucogram despite severe illness is another classic clue). Diagnosis is essential for long-term management planning but must not delay treatment of the immediate crisis.
Long-term Management and Welfare
Dogs surviving crisis require lifelong hormone replacement: desoxycorticosterone pivalate (DOCP, a depot mineralocorticoid injection every 25-30 days) or fludrocortisone (oral); and prednisolone (oral, low dose daily). Dogs receiving appropriate treatment have excellent long-term prognosis and good quality of life. Stress dosing (doubling prednisolone during illness, surgery, or significant stress events) prevents recurrence. Informed owners who recognise early relapse signs (lethargy, vomiting, anorexia) enable prompt treatment.