Addisonian crisis: which corticosteroid after the ACTH test
6-year-old West Highland White Terrier in Addisonian crisis. The ACTH stimulation test has been completed (cortisol < 1 µg/dL before and after) and the first fluid bolus has been given. It is still vomiting.
Which corticosteroid regimen is most appropriate now?
chevron_right Show answer and explanation
A. Oral fludrocortisone only, because the main problem is lack of aldosterone
The dog also has cortisol deficiency, which causes hypotension, hypoglycaemia and gastrointestinal signs. In addition, the oral route is unreliable while it is vomiting.
B. Immunosuppressive doses of prednisolone for several weeks
Stress doses tapered to physiological doses over a few days are sufficient. High doses increase the risk of gastrointestinal ulceration, to which these dogs are already predisposed.
C. No corticosteroid if electrolytes normalise with fluids
Fluids improve electrolytes transiently, but without glucocorticoid and mineralocorticoid the crisis recurs. The deficiency is permanent.
D. IV hydrocortisone CRI (glucocorticoid and mineralocorticoid effect) and, once eating, oral prednisolone plus mineralocorticoid (DOCP or fludrocortisone)
Correct. Once the test is done, a hydrocortisone CRI provides both effects and helps correct sodium and potassium. When the dog is eating it moves to oral prednisolone, tapered to a physiological dose, plus a mineralocorticoid.
lightbulb Key takeaway
Dexamethasone before the test; hydrocortisone or prednisolone after. Dexamethasone has no mineralocorticoid effect. Explain to the owner that the glucocorticoid dose must be increased during stress or illness.
Test yourself with 10 random questions
Endocrinology · 100 questions, a different test every time
Related questions
Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.