In advanced cases, facial myxedema may be present due to the accumulation of glycosaminoglycans in the dermis. Many hypothyroid dogs present dermatological changes such us dull hair coat, excessive shedding, hyperpigmentation, hair thinning, alopecia or pyoderma. Some of these dogs may develop hypothermia and seek for heat spots. Classical findings on history of these patients are lethargy, exercise intolerance, and weight gain. Hypothyroidism is a slow progressing disease.

Most hypothyroid dogs are middle aged (4-10 years) and there is not strong sex predisposition. Breeds with known predisposition are Doberman, Golden Retriever, Irish Setter, Miniature Schnauzer, Dachshund, Cocker Spaniel, and Airedale Terrier. Hypothyroidism usually occurs in medium to large size dogs. These hormones act on most organic tissue therefore, clinical findings are multi systemic, variable and non-specific. Therefore, the diagnosis of hypothyroidism in dogs should rely on a clinical diagnosis-including a careful history and physical exam, routine blood test, urinalysis, and exclusion of nonthyroidal illnesses and medications-and thyroid testing.Ĭanine hypothyroidism occurs as a consequence of an inadequate secretion of thyroid hormones. In the other hand, some dogs with confirmed hypothyroidism may have one or more thyroid function test within reference ranges (TSH and occasionally T4). Several factors like nonthyroidal diseases or medications can lower thyroid hormones (T4, FT4 and T3) concentrations in euthyroid dogs. Because of the variety of clinical signs and the limitations of thyroid tests, hypothyroidism is frequently misdiagnosed.

Hypothyroidism is a common endocrinopathy in dogs.

Books & VINcyclopedia of Diseases (Formerly Associate).VINcyclopedia of Diseases (Formerly Associate).

Euthyroid sick syndrome