Diabetes mellitus, hyperadrenocorticism, and hypothyroidism in a dog

An unusual combination of three endocrinopathies found in one dog is described. A six-year-old, spayed female, mixed-breed dog presented with polyuria, polydipsia, polyphagia, and weight loss. She was diagnosed with diabetes mellitus but was suspected of having insulin resistance and was diagnosed subsequently with hyperadrenocorticism. Persistent hypercholesterolemia led to the suspicion and eventual diagnosis of hypothyroidism. The dog has responded well to medical therapy, and her clinical signs and biochemical changes have resolved. A literature search did not identify a similar-reported polyendocrinopathy.