Editors

CamillaSchalin-Jäntti

Chronic Autoimmune Thyroiditis

Silent, usually symptomless inflammation of the thyroid gland
The most common cause of primary hypothyroidism Hypothyroidism
Increased concentration of thyroid peroxidase (TPO) antibodies is a diagnostic finding.
The condition is common: increased TPO antibody concentrations are found in 5-20% of general population. A certain share of these persons develop a clinical disease.
The disorder predisposes to a number of thyroid diseases, including hypothyroidism during pregnancy (requires treatment) and postpartum thyroiditis.
May also lead to enlargement of the thyroid gland (goitre) without hypothyroidism.

The thyroid gland may either become atrophic or goitrous, i.e. enlarged. The consistency of the thyroid gland is often solid on palpation. Sometimes a solitary nodule caused by the inflammation may be felt.
Serum TSH, free T4 and TPO antibody concentrations are determined. Increased TPO antibody concentration is a diagnostic finding and indicates an increased risk of hypothyroidism.
Possible hypothyroidism is revealed by laboratory tests. It will not develop in all patients.
Repeated determination of TPO antibody concentrations is of no use.

There is no specific treatment for chronic thyroiditis. Thyroxine may be used as needed for the treatment of subclinical or clinical hypothyroidism.
Treatment with glucocorticoids is not helpful.
Especially if a thyroid nodule does not decrease in size despite treatment or the size of the thyroid gland increases during follow-up, ultrasonography and, as necessary, fine-needle biopsy are performed and, if needed, the patient is referred to specialized care for assessment.
Due to cellular damage, autoimmune thyroiditis may sometimes induce transient thyrotoxicosis. Beta blockers are sufficient treatment. Follow the patient up to detect possible development of hypothyroidism.
Transient hypothyroidism that requires treatment often occurs after childbirth (within 4-8 months). It may be preceded by a 1-3-month phase of hyperthyroidism. Both conditions often resolve spontaneously but sometimes the patient develops permanent hypothyroidism requiring thyroxine treatment. Thyroid function tests should be checked before the next possible pregnancy.