Thyroiditis

Thyroiditis is enlargement of the thyroid gland from an autoimmune (antibodies to one’s own body) reaction. In this disease, the thyroid cells are damaged by antibodies. This is most commonly called Hashimoto’s thyroiditis, or autoimmune chronic lymphocytic thyroiditis. It is a common cause of enlargement of the thyroid in children, although it is more common in adults. Hashimoto’s thyroid is 10 times more common in females.

Children with thyroiditis usually present with swelling of the thyroid (thyromegaly) that is occasionally painful. These children usually do not have symptoms of hyperthyroidism, which helps distinguish them from thyromegaly in Grave’s disease. On exam, the gland can feel firm and granular. It is often enlarged, and can rarely compress the trachea causing hoarseness. Blood work demonstrates increased antibodies to the thyroid gland (microsomal and hemagglutinating). Sometimes these antibodies are negative at first, and will become positive (4 times higher than normal) 3-6 months later. Sometimes these children present with mild hyperthyroidism early, or later with hypothyroidism. The majority are euthyroid (normal thyroid hormone levels) and do not require intervention.

If a child with Hashimoto’s thyroiditis is symptomatic, medicines causing thyroid hormone depression can be initiated. Most children will have decrease in the size of the gland to 50% of the original size. Rarely, a child will continue to have an enlarged gland that causes symptoms and will require a subtotal thyroidectomy. In the setting of hyperthyroidism, propranolol can be used to control symptoms. Late in the disease, hypothyroidism can develop in 10% of patients and require thyroid hormone (thyroxine) replacement. These children may later be able to stop the thyroxine without recurrent symptoms. If a nodule develops in the future, evaluation for a thyroid cancer is indicated.

Acute thyroiditis is an infection of the thyroid gland which begins with pain over the thyroid gland, fever, and hoarseness. This may begin as an upper respiratory infection. Acute thyroiditis may be caused by a connection (fistula) to the back of the throat (pyriform sinus). On examination, the neck may be warm, red, swollen, and tender. Lymph nodes are often enlarged and tender. Although the child appears sick, they do not have hyperthyroidism (symptoms from increased thyroid hormone secretion). Blood work demonstrates an increased white blood cell count but normal thyroid hormone levels. An ultrasound of the neck may show an abscess within the thyroid gland which can then be drained. The culture of this fluid can guide antibiotic therapy. An esophagram (dye study of the esophagus) can be ordered to show the connection to the back of the neck.

Subacute thyroiditis results from a viral infection of the thyroid gland. It also often begins with an upper respiratory infection. Children then develop pain in the region of the thyroid gland. Again, these children are usually euthyroid (normal thyroid hormone levels). In addition to pain in the neck, these children usually have systemic symptoms: fever, weakness, fatigue, and muscle aches. Blood work demonstrates normal (or slightly elevated) thyroid hormone levels and normal antibody levels. After the symptoms resolve, children can develop asymptomatic enlargement of the gland, and later decreased thyroid function (hypothyroidism). Permanent hypothyroidism requiring hormone replacement is rare. Treatment is usually focused on relief of the systemic: acetaminophen and non-steroidal anti-inflammatory agents. Rarely, propanolol or steroids are necessary.