Clinical Biochemistry of Cushing Syndrome in Dogs

Abstract

The aim of the study is to determine clinical and paraclinical elements useful in the diagnosis of hyperadrenocorticism, given that the symptoms are varied and often similar to dermatitis or liver disease. Clinical signs in dogs with hyperadrenocorticism were especially of dermatological nature (bilateral alopecia, thin skin along with elastosis and hyperpigmentation, calcinosis cutis and muscle weakness and abdominal enlargement - „potbelly”), accompanied by polyuria and polydipsia. Blood tests performed on 14 dogs of different breed, age and gender revealed moderate hyperglycemia (143.4±3.3 mg/dl), hypercholesterolemia (332±2.9 mg/dl), increased serum alkaline phosphatase (378±3.8 UI/L), alanine aminotransferase (ALT=93.26±2.6 UI/L), aspartate aminotransferase (AST=89.72±2.3 UI/L) and abnormal plasma cortisol (50±3.5 ng/dl). Thorough ultrasonography revealed hypertrophy of the adrenal glands (2.92x1.43 cm). The histopathologic lesions include active metabolic cells (big, rich colored and strong-cored), containing lipid structures (steroids’ precursors) and metabolic inactive cells (small, dark colored, pyknotic cored or rich in heterochromatin). Hyperglycemia, polyuria / polydipsia or elevated serum alkaline phosphatase without a significant increase in serum transaminases (AST and ALT) raises suspicion of Cushing's syndrome. If these biochemical diagnostic elements evolve along with dermatological signs (bilateral alopecia, hyperpigmentation, muscle weakness), the diagnosis of Cushing's syndrome is more likely.