We've all heard the term, but is atypical hyperadrenocorticism real? This syndrome refers to dogs with clinical signs and
laboratory abnormalities suggestive of hyperadrenocorticism but with normal cortisol concentrations after low-dose dexamethasone
suppression (LDDS) and ACTH testing.
In her presentation, "Atypical canine hyperadrenocorticism: Is it real?" Dr. Ellen Behrend from Auburn University's College
of Veterinary Medicine presented evidence for and against the existence of this sex-hormone-mediated disease, comparing research
from the standpoint of bilaterally symmetric alopecia, sex hormone assays, and response to treatment.1 Overall, her findings elucidate the lack of specificity of sex hormone assays since nonadrenal illness can also elevate
these hormones. Additionally, some patients demonstrate clinical response to treatment with drugs such as mitotane and trilostane
despite an increase in sex hormone concentrations, so other mediators such as enzymes or growth factors may also play a role.
While atypical Cushing's may exist as a syndrome, much more research is still needed to understand this disease entity.
This "Presentation Recap" summary from the 2011 American College of Veterinary Internal Medicine (ACVIM) Forum, which took
place in Denver, Colo., was contributed by Jennifer L. Garcia, DVM, DACVIM, a veterinary internal medicine consultant in Houston,
1. Behrend EN. Atypical canine hyperadrenocorticism: Is it real? Presented at the Annual Meeting of the American College of
Veterinary Internal Medicine; June 2011.