Diagnosis and management of concurrent diabetes mellitus and hyperadrenocorticism in thirty dogs.

Concurrent diabetes mellitus and hyperadrenocorticism were diagnosed in 30 dogs over a 2-year period. Clinical signs included polyuria, hepatomegaly, polyphagia, abdominal distension, truncal alopecia, anorexia, and vomiting. Because of the similar clinical and laboratory findings for hyperadrenocorticism and diabetes mellitus, hyperadrenocorticism was initially overlooked in some dogs. Insulin resistance, characterized by high daily insulin requirements, developed in the diabetic dogs with untreated hyperadrenocorticism. Therapy with o,p'-DDD resulted in precipitous declines in insulin requirements. By lowering the dosage of o,p'-DDD and supplementing with glucocorticoids during the o,p'-DDD loading period, serious hypoglycemia was avoided. Control of coexisting hyperadrenocorticism lessened the severity of the diabetes mellitus, but insulin therapy remained a necessity in all dogs.