Hashimoto's Thyroiditis

Question 1

What is Hashimoto’s thyroiditis?

Answer 1

A chronic autoimmune disorder of the thyroid gland causing progressive destruction of thyroid tissue

Question 2

What is the typical thyroid state in Hashimoto’s thyroiditis?

Answer 2

Hypothyroidism, although a transient thyrotoxic phase may occur early

Question 3

Why can Hashimoto’s thyroiditis initially cause thyrotoxicosis?

Answer 3

Destruction of thyroid follicles leads to release of preformed thyroid hormones

Question 4

Which sex is most commonly affected by Hashimoto’s thyroiditis?

Answer 4

Women

Question 5

How much more common is Hashimoto’s thyroiditis in women compared to men?

Answer 5

Approximately 10 times more common

Question 6

What are the typical clinical features of Hashimoto’s thyroiditis?

Answer 6

Features of hypothyroidism such as fatigue, weight gain, cold intolerance and constipation

Question 7

What are the typical thyroid examination findings in Hashimoto’s thyroiditis?

Answer 7

A firm, non-tender goitre

Question 8

Which antibody is most strongly associated with Hashimoto’s thyroiditis?

Answer 8

Anti-thyroid peroxidase (anti-TPO) antibodies

Question 9

In what proportion of patients are anti-TPO antibodies positive?

Answer 9

More than 90%

Question 10

Are anti-thyroglobulin antibodies specific for Hashimoto’s thyroiditis?

Answer 10

No, they are less specific but present in around 60–80% of cases

Question 11

Which autoimmune diseases are commonly associated with Hashimoto’s thyroiditis?

Answer 11

Coeliac disease, type 1 diabetes mellitus and vitiligo

Question 12

Why are patients with Hashimoto’s thyroiditis at increased risk of other autoimmune diseases?

Answer 12

Shared autoimmune pathophysiology and genetic susceptibility

Question 13

Which malignancy is Hashimoto’s thyroiditis associated with?

Answer 13

MALT (mucosa-associated lymphoid tissue) lymphoma of the thyroid

Question 14

Why does Hashimoto’s thyroiditis increase the risk of MALT lymphoma?

Answer 14

Chronic lymphocytic infiltration of the thyroid promotes lymphoid tissue formation

Question 15

What is the most common cause of hypothyroidism in iodine-sufficient regions?

Answer 15

Hashimoto’s thyroiditis