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CamillaSchalin-Jäntti

Chronic Autoimmune Thyroiditis

Essentials

  • 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.

Diagnosis

  • 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.

Treatment

  • 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.