Paediatrics: Thyroiditis

Thyroiditis

Inflammation of the thyroid gland that may result in goitres. Initial thy-rotoxicosis is usually followed by hypothyroidism. Recognized causes in-clude:

·  autoimmune thyroiditis (Hashimoto’s);

·  acute suppurative (pyogenic) thyroiditis;

·  subacute (de Quervain) thyroiditis.

Autoimmune thyroiditis (Hashimoto’s)

This is the most common cause of thyroid disease in childhood and ado-lescence and is the most common cause of hypothyroidism in developed countries.

·  Characterized by lymphocytic infiltration of the thyroid gland and early thyroid follicular hyperplasia, which gives way to eventual atrophy and fibrosis.

·  Associated with a positive family history of thyroid disease. There is an increased risk of other autoimmune disorders (e.g. type 1 diabetes).

·  4–7 times more common in females than in males.

·  Children with Down’s or Turner’s syndrome are at increased risk.

·  Peak incidence is in adolescence, although may occur at any age.

Presentation

Clinical presentation is usually insidious with a diffusely enlarged, non-tender, firm goitre. Most children are asymptomatic and biochemically eu-thyroid. Some children may present with hypothyroidism. A few children may have symptoms suggestive of hyperthyroidism, i.e. ‘Hashitoxicosis’.

The clinical course is variable. Goitres may become smaller and disap-pear or may persist. Many children who are initially euthroid eventually develop hypothyroidism within a few months or years of presentation. Periodic follow-up is therefore necessary.

Investigations

·  Diagnosis can be established by thyroid biopsy (but not indicated).

·  Thyroid biochemistry may be normal or abnormal.

·  Anti-microsomal thyroid antibody titres are usually raised, whereas anti-thyroglobulin titres are increased in only approximately 50%.

Treatment

Only required for the management of either hypothyroidism or hyperthyroidism if present.

Acute suppurative thyroiditis

This is uncommon. Often preceded by respiratory tract infection. Organisms include Staphylococcus aureus, streptococci, and Escherichia

coli (rarely, fungal infection). Abscess formation may occur.

·Presentation is with painful tender swelling of thyroid.

·Thyroid function is usually normal; however, hyperthyroidism may occur.

·Recurrent infection should raise suspicion of the presence of a thyroglossal tract remnant.

·Treatment requires administration of antibiotics and surgical drainage of abscess if present.

Subacute thyroiditis (de Quervain’s)

·A self-limiting condition of viral origin, associated with tenderness and pain overlying the thyroid gland.

·Symptoms of thyrotoxicosis may be present initially, although hypothyroidism may develop later.

Treatment includes non-steroidal anti-inflammatory agents and, in severe cases, corticosteroids (prednisolone). Beta-blocker therapy, e.g. propranolol, may help to control thyrotoxic symptoms.