Hyperthyroidism

Grave’s disease (hyperthyroidism) is generally diagnosed in adults, but can be seen in children. This can cause enlargement of the thyroid gland (goiter). Although this usually occurs in older children, it can be seen in infants of mother’s with Grave’s disease. Infants generally respond to medicines (iodine and propylthiouracil) and do not require surgery.

Childhood symptoms of hyperthyroidism include nervousness, irritability, diarrhea, weight loss, insomnia, and poor performance in school. On physical examination, these children have exophthalmos (protruding eyes), high blood pressure, fast heart rate, and weight loss. The thyroid is often enlarged, up to 4 times the normal size. In order to confirm the diagnosis of hyperthyroidism, blood is checked for increased levels of thyroid hormones (T4 and T3). TSH, a hormone from the pituitary gland which stimulates the thyroid, should be low unless there is a pituitary tumor. A thyroid scan may also demonstrate increased uptake (activity) throughout the gland.

Treatment of hyperthyroidism begins with medical therapy, with surgery reserved for children who do not respond to the medicine. Propylthiouracil or methimazole are usually initiated to treat hyperthyroidism. Propanolol is sometimes added because it quickly controls some of the symptoms (fast heart rate, shakiness). Symptoms should be improved with return of thyroid hormone levels to normal, usually within 2 months.

Medicines fail to correct the hyperthyroidism in up to 75% of children at two years. Allergic reactions to the medicines may cause early failures. In this setting there are two options, treatment with iodine-131 or surgery (thyroidectomy). Iodone-131 is used more commonly in adults. In children, there is more concern about causing hypothyroidism, the risk of genetic damage affecting offspring, and the increased risk of future thyroid carcinoma. The advantages include ease of therapy (no surgery), low cost, and safety. Currently, most physicians think risks to fertility or future offspring is minimal.

If surgery is planned, there is an increased risk of hyperthyroidism with general anesthesia. This is called thyroid storm, and includes high blood pressures, fast heart rate, and increased body temperature. Propanolol is therefore given preoperatively to control symptoms, and sometimes is continued after surgery. Some surgeons recommend total thyroidectomy. This eliminates the risk of recurrent hyperthyroidism, but may increase the risk of surgery (injury to the nerves or parathyroid glands). Other surgeons recommend leaving a small portion (2-4 grams) of the thyroid gland near the parathyroid glands. This usually cures the hyperthyroidism and reduces the risk of injury to the parathyroid glands. The risk of this approach is having to re-operate for recurrent hyperthyroidism, which is more risky because of scarring in the neck. After surgery, children will require thyroid replacement for life.