Thyroiditis (Thyroid Gland Inflammation)

Thyroiditis (ICD-10 E06.-) is the inflammation of the thyroid gland (thyroidea). One can distinguish the following forms according to ICD-10:

• Acute thyroiditis (ICD-10 E06.0) – infection of the thyroid gland caused by bacteria, viruses, fungi, etc.; mainly staphylococci, streptococci; Aspergillus, Candida.
• Subacute thyroiditis (E06.1).
  • Thyroiditis de Quervain (subacute granulomatous thyroiditis) – relatively rare form of thyroiditis that often occurs after a respiratory infection; circa five percent of all thyroiditis cases.
  • Granulomatous thyroiditis
  • Non-purulent thyroiditis
  • Giant cell thyroiditis
• Chronic thyroiditis with transient hyperthyroidism (E06.2) – with transient hyperthyroidism.
• Autoimmune thyroiditis (AIT) (E06.3).
  • Hashimoto’s thyroiditis (hypertrophic) – presents as chronic lymphocytic thyroiditis with hypothyroidism [see below Hashimoto’s thyroiditis].
  • Hashitoxicosis (transitory) – short-term hyperthyroidism (hyperthyroidism), often occurring at the onset of Hashimoto’s thyroiditis.
  • Lymphocytic thyroiditis
  • Struma lymphomatosa (Hashimoto’s)
• Drug-induced thyroiditis (synonym: drug-induced thyroiditis; E06.4).
• Other chronic thyroiditis (E06.5).
  • Chronic fibrosing thyroiditis
  • Thyroiditis, iron-hard
  • Riedel’s struma (chronic fibrosing thyroiditis) – extremely rare form of thyroiditis.
• Thyroiditis, unspecified (E06.9).

Furthermore, the following forms can be distinguished:

• Silent thyroiditis (silent thyroiditis) – thyroiditis belonging to the autoimmune thyroiditis with a mild course.
• Postpartum thyroiditis (PPT; postpartum thyroiditis) – first occurrence of autoimmune thyroiditis (AIT) up to 12 months after delivery with antibody detection in existing euthyroidism (normal thyroid function); in about four percent of pregnant women.
• Radiation thyroiditis – after irradiation with radioactive iodine; self-limiting.
• Carcinoma-associated thyroiditis – thyroiditis occurring in the setting of a malignant neoplasm.
• Parasitic thyroiditis – caused by parasites such as Echinococcus (tapeworms) or Strongylidae (palisade worms).

Sex ratio: in thyroiditis de Quervain, women are up to 7 times more likely to be affected than men. In Hashimoto’s thyroiditis, the sex ratio males to females is 1: 9. Peak incidence: the maximum incidence of thyroiditis de Quervain is in the between the fourth and fifth decade of life.Hashimoto’s thyroiditis predominantly in the 3rd and 5th decade of life. The prevalence (disease incidence) of Hashimoto’s thyroiditis is 5-10% (in Germany).The prevalence of postpartum thyroiditis is 0.9-11.7%.The acute (infectious) thyroiditis is rare. The incidence of thyroiditis de Quervain is about 5 diseases per 100,000 population per year. Course and prognosis: Approximately 5-25% of all subacute thyroiditis cases are clinically silent (painless thyroiditis). In most forms of thyroiditis, transient thyroid dysfunction (hyperthyroidism or hypothyroidism) often occurs during the course of the disease. After thyroiditis is over, euthyroid metabolism (normal thyroid function) usually remains. If there is extensive destruction of the thyroid parenchyma, persistent (“persisting”) hypothyroidism requiring substitution occurs. This is often the case in Hashimoto’s thyroiditis. In thyroiditis de Quervain, this occurs in only 2-5 (-15) % of cases.In postpartum thyroiditis, after initial hyperthyroidism (hyperthyroidism; 1-6 months after delivery; duration 1-2 months), there is later hypothyroidism (3-8 months after delivery), which then changes to euthyroidism (normal thyroid function). Hyperthyroidism is not treated thyrostatically, but symptomatically with a beta-blocker. In about 20-64% of patients with postpartum thyroiditis, hypothyroidism is permanent and substitution is necessary.