Hypothyroidism is one of the commonest endocrine diseases of dogs and one of the most often misdiagnosed. Almost all cases are primary: the thyroid gland is destroyed, thyroxine (T4) falls and metabolism slows. The exam focus is less on spotting the classic dog and more on reading thyroid tests correctly in a dog that may simply be ill, on medication or a sighthound.
Key facts
Hypothyroidism at a glance- Species / system: Dog; thyroid gland and the hypothalamic-pituitary-thyroid axis.
- Cause: over 95% primary, from lymphocytic (autoimmune) thyroiditis or idiopathic thyroid atrophy. Secondary (pituitary) disease is uncommon.
- Typical patient: middle-aged (4–10 years), usually medium to large breed, no sex predilection. Dobermans, Boxers, Golden Retrievers, Irish Setters, Cocker Spaniels, Dachshunds, Miniature Schnauzers and Airedales are among the predisposed breeds.
- Classic presentation: lethargy, weight gain without more appetite, heat seeking and non-itchy bilaterally symmetrical alopecia, with hypercholesterolemia and a mild nonregenerative anemia.
- Key tests: total T4 to screen; free T4 by equilibrium dialysis plus TSH to confirm.
- Not zoonotic or reportable.
What's inside
11 sections in the full guide- Key facts
- How the NAVLE tests this
- Cause and pathophysiology
- Clinical signs
- Diagnosis
- Differential diagnoses
- Treatment and management
- Prognosis
- Quick review
- Test yourself
- References
The full guide also has 5 tables, 3 figures, 3 self-test questions and 19 references, available to NAVLE members.
Read the full study guide
The full guide is part of every NAVLE plan, with diagnosis and treatment tables, figures, a quick review and self-test questions. Start a free trial to try the question bank, or log in if you are already a member.