Hormone replacement therapy:
According to Dr. LaFranchi, a pediatric endocrinologist since the late 1970s, “The treatment for hypothyroidism is pretty straightforward. We compensate for the hormone deficiency by giving the teen a synthetic preparation called levothyroxine once a day. Sometimes it takes the physician a while to settle on the correct dose, but we use a formula based on body weight, so that gives us a good idea of where to start.” As with insulin therapy in diabetes, thyroid-hormone replacement is for life. Fortunately, the majority of young people take the oral tablets without any problems. Once the TSH level is stabilized, thyroid function needs to be checked only once per year, barring any recurrences.
“Hyperthyroidism is a little trickier to treat,” says Dr. LaFranchi. “There are essentially three options. One is to give so-called antithyroid drugs [propylthiouracil, methimazole], which shut off production of excess thyroid hormone until the level is in a normal range.” Twelve to eighteen months of therapy produce a prolonged remission in about one-fourth of all patients.
Another class of drugs, beta-adrenergic blockers, inhibits the action of thyroid hormone. While agents such as atenolol, metoprolol, nadolol and propranolol do not actually lower the excessive levels of circulating thyroid hormone, beta-blockers usually bring rapid relief from many of the disease’s symptoms.
Because drug therapy usually does not cure hyperthyroidism, it has been surpassed in recent years by radioiodine ablation. The thyroid appropriates iodine from the circulation in order to make thyroxine. In this ingenious therapy, the patient swallows a capsule or liquid containing radioactive iodine, known as I-131. The gland absorbs the radionuclide, which proceeds to destroy (ablate) the cells responsible for secreting thyroid hormone.
Perhaps the idea of ingesting a radioisotope sounds hazardous, but radioiodine ablation is an extremely safe procedure. Though the tasteless, odorless substance passes from the body in a matter of days, it generally takes three to six months for the thyroid to fully react by shrinking in size and allowing the concentration of thyroid hormone to return to normal. If necessary, a second dose can be given. Most patients treated this way develophypothyroidism anywhere from several months to many years later. At that point, they go on permanent thyroid-hormone replacement therapy.
The third option, rarely exercised, consists of an operation to remove part of the thyroid. Thyroidectomy is curative. However, patients who require extensive surgery may become hypothyroid some time in the future.