Pituitary tumour shrinkage and diabetic remission in two cats with Cushing syndrome treated with cabergoline

We describe two cats with diabetes mellitus and Cushing's syndrome. Diabetes mellitus was initially managed with insulin glargine (Lantus; Sanofi-Aventis, Paris, France), nutritional therapy and continuous glucose monitoring. Hypercortisolism was suspected based on severe hypertension (Case 1), and insulin resistance in combination with typical clinical features of Cushing's syndrome (Case 2). Endocrine testing revealed non-suppressible cortisol concentrations on low-dose-dexamethasone suppression test, elevated endogenous adenocorticotrophic hormone (ACTH) concentration and pituitary enlargement on computed tomography. Cabergoline (Holiday®, Holliday-Scott S.A., Buenos Aires, Argentina) was initiated at a dose of 10 μg/kg po every 48 hours targeting both the pituitary tumour and hypercortisolism. In Case 2, the cabergoline dosage was gradually increased to a final dose of 10 μg/kg po every 12 hours. Both cats achieved diabetic remission within 1 and 6 months of treatment, respectively. Serial monitoring demonstrated a decrease in endogenous ACTH concentrations and a reduction in pituitary volume of 29% of baseline (Case 1) and of 52% of baseline (Case 2) after 8 months of treatment. These findings suggest that cabergoline may be a potential medical treatment option in cats with pituitary-dependent hypercortisolism.