Cushing's Syndrome associated with diabetes mellitus in a Persian cat: clinical features, diagnosis, and therapeutic management.

The association between Cushing's syndrome (CS) and diabetes mellitus (DM) in cats is rarely reported. Complications related to hypercortisolism and persistent hyperglycemia may occur, which may complicate the control of both endocrinopathies. This report describes the case of a 10-year-old Persian cat diagnosed with CS and DM. The patient presented with polyuria, polydipsia, chronic dry seborrhea on the dorsal region and flanks, and lack of hair regrowth on the abdomen. Through the dexamethasone suppression test (0.1 mg/kg) and the presence of persistent hyperglycemia with elevated fructosamine levels and glycosuria, diagnoses of Cushing's syndrome and DM were established. Treatment was initiated with trilostane (2 mg/kg PO BID) for CS and insulin glargine (2 IU/animal SC BID) for DM, resulting in stabilization of blood glucose, cortisol concentrations, and the patient's clinical condition, although cutaneous fragility persisted for a prolonged period. Diagnostic investigation for hypercortisolism should be considered in cats with DM to allow earlier diagnosis, reduce underdiagnosis, and improve the availability of epidemiological and clinical data on this association. The diagnostic approach and clinical management described may aid veterinarians in recognizing this coexistence and anticipating therapeutic challenges, such as persistent cutaneous fragility despite cortisol control.