Suspected hyperadrenocorticism in an Atlantic bottlenose dolphin (Tursiops truncatus): Diagnostic approach and treatment with ketoconazole

Abstract

A 35-year-old female Atlantic bottlenose dolphin (Tursiops truncatus) presented with lethargy, dysorexia, obesity and locomotor difficulties. An abnormal deposition of fat and superficial skin lesions was observed. Laboratory findings showed lymphopenia and eosinopenia associated with hypercholesterolemia. Endocrinological assessment revealed chronically increased serum cortisol values associated with increased plasma adrenocorticotrophic hormone (ACTH) concentration. ACTH-dependent hyperadrenocorticism, also known as Cushing's syndrome, was strongly suspected. The bottlenose dolphin was treated with ketoconazole (2.3 mg/kg every 12 hours) and prednisone (0.03 mg/kg every 48 hours), which resulted in an improvement in clinical signs, except for obesity. Long-term treatment with ketoconazole and prednisolone did not cause any adverse effects. However, the authors recommend avoiding concurrent hormonal treatment with altrenogest as it might cause a relapse of hyperadrenocorticism or drug-drug interaction with ketoconazole. Endocrinopathies are rare in cetaceans but this case highlights the importance of considering hyperadrenocorticism as a differential diagnosis in dolphins with obesity and skin lesions.