Cushing's Syndrome with Concurrent Diabetes Mellitus in a Rhesus Monkey

Cushing's syndrome is the clinical expression of the overproduction of glucocorticoids and is well recognized in both human and veterinary medicine. Spontaneous diabetes mellitus is well known in Macaca spp., however the occurrence of hyperadrenocorticism and diabetes mellitus concurrently in macaques has not been reported previously. This unusual case presents a rare opportunity to examine the relationships between two important endocrine diseases in a nonhuman primate. A male, 14-year-old rhesus macaque (Macaca mulatta) was diagnosed with hyperadrenocorticism and concurrent diabetes mellitus. Initially, the monkey had mildly elevated blood glucose values upon routine semi-annual physical examination. Further diagnostic work-up demonstrated hypercortisolism. Adrenocorticotropic hormone-dependent Cushing's syndrome was subsequently diagnosed in light of results from dexamethasone testing, magnetic resonance imaging, and computed tomography scans. A therapeutic course of L-deprenyl (Anipryl(r)) was begun, and 8 weeks later, insulin therapy was initiated. The patient responded well to insulin therapy, however the dosage was rapidly increased. After 6 months, Anipryl(r) therapy was determined to be of little or no value, and ketoconazole was selected as the drug of choice to control the hypercortisolism. The monkey has shown remarkable improvement with the dual therapies of insulin and ketoconazole. Approximately 2 months after the initiation of ketoconazole therapy, the animal was returned to an experimental protocol under the conditions of twice-daily treatment and strict dietary control. The ongoing plan for clinical management includes periodic blood glucose and liver function surveillance.