Alternate Names: Atypical subacute thyroiditis; Hyperthyroiditis; Lymphocytic thyroiditis; Subacute lymphocytic thyroiditis; Lymphocytic thyroiditis with spontaneously resolving hyperthyroidism

Causes and Risks: The cause of this type of thyroiditis is unknown. The thyroid gland becomes infiltrated with lymphocytes (a type of white blood cell). The disease affects women more commonly than men and usually develops between 13 and 80 years old. The symptoms are those of hyperthyroidism (overactivity of the thyroid gland) and may last for 3 months or less. Risk factors are being female, over 30 years old, and having a current pregnancy.

Prevention: Prevention is unknown.

Symptoms:

• weight loss
• increased appetite
• nervousness restlessness
• heat intolerance
• increased sweating
• fatigue
• muscle cramps
• frequent bowel movements
• menstrual irregularities

Signs and Tests: A physical examination reveals an enlarged thyroid gland. The pulse (heart rate) may be rapid.

• Radioactive iodine uptake is decreased.
• Serum T3 and T4 are elevated.
• A thyroid biopsy shows infiltration with lymphocytes.

Treatment: Treatment is symptomatic. Beta-blockers (Propranolol and others) relieve the symptoms of rapid heart rate and excessive sweating.

Prognosis: The disease is usually resolved within 1 year, with the acute phase ending in 3 months. Some people may develop hypothyroidism as a result of this condition, so regular follow-up is recommended.

Complications:

• hypothyroidism

Call your health care provider if symptoms of this disorder develop.

If you have had this disease, regular follow-up is recommended to watch for the development of hypothyroidism.