Just Ask the Expert: Testing for concurrent diabetes and hyperadrenocorticism

Dr. Bruyette welcomes endocrinology questions from veterinarians and veterinary technicians.

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Q. Yesterday, I saw a 7-year-old neutered male obese (112-lb) Labrador retriever for evaluation of lethargy, partial anorexia, weight loss (10 lb in three months), and heavy panting. The owner thinks the dog is drinking more water. Abnormal CBC results include moderate erythrocytosis, lymphopenia, and eosinopenia. The serum alkaline phosphatase activity is 395 mU/ml, and the glucose concentration is 310 mg/dl. The dog has glucosuria (4+) and a urine specific gravity of 1.014. The urine cortisol:creatinine ratio is 2.96. Do I continue screening for hyperadrenocorticism, or should I treat for diabetes while attempting to gradually reduce this dog's weight?

David S. Bruyette, DVM, DACVIM VCA

A. This is a great question and common clinical problem. In general, we try to regulate the diabetes before attempting to diagnose hyperadrenocorticism. Although this dog's UCCR result is normal, diabetes mellitus and many other nonadrenal illnesses can affect the pituitary-adrenal axis, resulting in false positive results on the UCCR, ACTH stimulation test, and the low-dose dexamethasone suppression test. I would treat the diabetes first and, once you think you have adequate glycemic control, then revisit whether the dog may have concurrent hyperadrenocorticism. If you think there is an indication to evaluate the pituitary-adrenal axis, I would start with the ACTH stimulation test, as it appears to be less affected by concurrent disease.

David S. Bruyette, DVM, DACVIM VCA

West Los Angeles Animal Hospital

1818 S. Sepulveda Blvd.

West Los Angeles,

CA 90025

Veterinary Diagnostic Investigation and Consultation

26205 Fairside Road

Malibu, CA 90256