Combined atypical primary hypoadrenocorticism and primary hypothyroidism in a dog

Abstract

A dog with combined atypical primary hypoadrenocorticism and primary hypothyroidism is described. The dog presented with waxing and waning, vague complaints since more than a year and had been treated with several drugs without complete resolution of signs. Based on the abnormalities on physical examination, blood examination and abdominal ultrasonography, atypical primary hypoadrenocorticism and primary hypothyroidism were diagnosed. Glucocorticoid supplementation was started and gradually tapered to maintenance rate because of polydipsia. Ten days later, levothyroxine supplementation was started at a very low dose and was gradually increased based on serum total thyroxine concentrations. The dog rapidly improved and recovered completely. Follow-up over a one-year period did not reveal new abnormalities. The presence of combined primary hypoadrenocorticism and primary hypothyroidism has been infrequently described in dogs and may resemble the Schmidt’s syndrome in humans.