Hashimoto thyroiditis

Hashimoto thyroiditis, also called chronic autoimmune hypothyroidism is an autoimmune condition characterised by CD8-mediated destruction of the thyroid parenchyme. It’s the most common cause of chronic hypothyroidism in western countries, affecting 3 – 5 per 10 000. It mostly affects middle-aged females.

It’s associated with other autoimmune diseases and with HLA-DR5.

Clinical features

In the early phase thyrotoxicosis develops as the destroyed cells release preformed hormones, sometimes called “hashitoxicosis”. In this phase, there’s a non-tender and painless goitre.

Later, hypothyroidism occurs in the chronic phase, as the number of cells decreases. In this phase, the thyroid may be normal or small. Hashimoto causes painless goitre.

The patient may present in any of these stages. The goitre may be diffuse or nodular.

Diagnosis and evaluation

The following features are typical for Hashimoto:

• Typical clinical features
• Ultrasound findings (inhomogenous, hypoechogenic thyroid)
• Normal leukocyte count
• Moderately elevated ESR
• Initial thyrotoxicosis followed by hypothyroidism
• Elevated anti-thyroid antibodies (anti-TPO, anti-Tg)

The anti-thyroid antibodies are the main factors in the diagnosis of Hashimoto thyroiditis. Ultrasound is rarely indicated in the evaluation of Hashimoto thyroiditis.

Treatment

The treatment of Hashimoto thyroiditis is lifelong L-thyroxine replacement therapy, as for other causes of hypothyroidism. Immunosuppressants are not helpful in the treatment of Hashimoto thyroiditis.