[Hypothyroidism in dogs: an overview]

Hypothyroidism is one of the most common endocrinopathies in dogs. In rare cases, it may be associated with further endocrinopathies. The most common combination is the con-currence of hypothyroidism and hypoadrenocorticism. The diagnosis of hypothyroidism is based on the measurement of thyroid hormones (T4/fT4) and thyroid stimulating hormone (TSH). As thyroid hormone concentrations in the blood are influenced by various factors (e. g. systemic diseases or drugs), test results must be interpreted in conjunction with complaints demonstrated by the patient. In cases when diagnosis is not definite, stimulating tests or diagnostic imaging techniques (ultrasound, scintigraphy) are advisable. Dogs with hypothyroidism should be diagnosed and treated with thyroid hormones. When addiditional clinical signs are not consistent with hypothyroidism, co-existing additional endocrinopathies need to be considered. Furthermore, when treatment fails to result in the expected clinical response, the diagnosis of hypothyroidism must be subject to critical re-evaluation. This article provides an overview of the current diagnostic and treatment methods in canine hypothyroidism.