New guidelines highlight diagnostic pitfalls in canine Addison’s disease

Canine Addison’s disease kills through misdiagnosis—its elusive symptoms and complex diagnostics cause vets to miss cases until crisis strikes. The American Animal Hospital Association has released updated diagnostic criteria designed to catch the disease earlier and prevent preventable collapse.

For veterinary practices, the central risk in canine Addison’s disease is missed diagnosis rather than lack of treatment. The 2023 AAHA endocrine guidelines class crisis cases as hypovolaemic shock and advise that a resting cortisol result below 2 mcg/dL should be followed by an ACTH stimulation test, while a value above that level largely rules the disease out.

The condition is uncommon, affecting an estimated 0.5% to 2% of dogs, but its presentation is commercially and clinically awkward because signs are intermittent, stress-related and easily mistaken for gastrointestinal or renal disease. Merck says low sodium-to-potassium ratios below 27 are suggestive rather than diagnostic, and crisis patients may present with hypotension, severe hyperkalaemia, hypoglycaemia and azotaemia. Cornell adds that “atypical” cases may show cortisol deficiency with normal sodium and potassium, complicating screening.

Possible causes extend beyond idiopathic disease. PetMD and Cornell include infection, adrenal cancer, poor adrenal blood supply, over-treatment for Cushing’s disease and abrupt steroid withdrawal. After stabilisation, AKC and VCA describe standard maintenance as monthly DOCP injections, sold as Percorten-V or Zycortal, plus daily prednisone, although fludrocortisone remains an oral alternative. PetMD says many dogs improve within 24 hours; VCA says prognosis is generally good to excellent once stabilised.