What is food-induced Cushing’s disease?
Food-induced (also called meal-induced) Cushing’s is a very rare form of the disease. Unlike other dogs, those with this condition release cortisol when any food enters their stomach. It’s thought to occur because of a congenital defect, in which a hormone (glucagon inhibitory peptide or GIP) that's released during eating binds to receptors on the adrenal gland and triggers the production of cortisol. Dogs with food-induced Cushing’s are typically diagnosed at around two to five years old.
Clinical Signs
The clinical signs of food-induced Cushing's disease are similar to the clinical signs of other types of Cushing’s. These signs include frequent urination and/or accidents in the house, increased water intake, a ravenous appetite, muscle wasting, an enlarged abdomen, and hair loss. And bloodwork will most likely show an elevated alkaline phosphatase (ALP).
Diagnosis
Most veterinarians use a urine test to diagnose food-induced Cushing's. For this test, a dog is normally fasted for 12 hours overnight, and then the owner obtains a urine sample in the morning. Next, the owner feeds the dog and collects another urine sample four hours afterwards. Both samples should, ideally, be collected at home, so that the stress of visiting the vet doesn’t influence the results. To obtain a diagnosis, the veterinarian submits the urine to a laboratory, where the ratio of cortisol to creatinine (UCCR ratio) in each sample is determined. In most dogs with food-induced Cushing’s disease, the UCCR ratio after eating will be double the UCCR ratio before eating.
Treatment
Vetoryl (trilostane), which should be given two to three hours before every meal. Your veterinarian will periodically monitor treatment with an ACTH stimulation test. For food-induced Cushing's, the ACTH test is conducted four hours after a dog’s morning meal (six to seven hours after treatment with Vetoryl).
Reference (external)
Meal-Induced Hyperadrenocorticism in dogs: not to be overlooked, by Carla Johnson, DVM