Hypothyroidism is more common in adults, but it can also occur in teens. With hypothyroidism, the thyroid gland in the front of the neck fails to produce enough thyroid hormones. Because thyroid hormones influence growth, development and puberty, teens with reduced thyroid hormones can have signs and symptoms related to these processes. Symptoms of low thyroid function in teens are often vague, but it's important to spot them because simple treatment can help prevent long-term problems.
Causes and Risk Factors
Hypothyroidism is more common in girls than boys. Hypothyroidism in teens is most often caused by Hashimoto thyroiditis, an autoimmune disorder in which the immune system mistakenly attacks the thyroid gland. Teens with other autoimmune diseases -- such as type 1 diabetes -- or a family history of Hashimoto thyroiditis have an increased risk of developing this disorder. Teenagers with certain genetic conditions, including Down syndrome, are also at increased risk. Other causes of hypothyroidism include side effects from certain medications and problems with the hypothalamus or pituitary gland. Iodine deficiency, exposure to pesticides or chemicals, radiation therapy, thyroid surgery and viral illnesses are possible, but uncommon, causes of hypothyroidism.
Unique Signs and Symptoms
Undiagnosed hypothyroidism in children and teens often causes problems with growth and development. Teens with hypothyroidism often gain weight, but their rate of growth can become slower. They may be shorter and look younger than expected for their age. Untreated hypothyroidism can also delay puberty. Boys may have increased testicle size, and girls may not develop breasts or start menstruating. If hypothyroidism develops after a teenage girl has started menstruating, she may experience heavy or irregular bleeding. Low thyroid function can also lead to mood and behavioral problems in teens, as well as difficulties with school performance.
Other Signs and Symptoms
In teens with early hypothyroidism, symptoms can be subtle and difficult to spot. But as metabolism slows, the lack of thyroid hormones affects multiple body systems, causing signs and symptoms that mirror those of hypothyroidism in adults:
-- fatigue, sluggishness, depression
-- difficulty concentrating and forgetfulness
-- cold sensitivity
-- dry skin and brittle hair and nails
-- facial puffiness
-- hoarseness and thyroid gland enlargement
-- muscle and joint pain and stiffness
Diagnosis and Treatment
Blood tests are used to diagnose hypothyroidism. The two most important tests are the level of a thyroid hormone called thyroxine (T4) and the level of thyroid-stimulating hormone (TSH). The pituitary gland produces TSH to stimulate the thyroid to release hormones. With most causes of hypothyroidism, the pituitary gland produces large amounts of TSH in a futile attempt to stimulate the thyroid to produce adequate amounts of thyroid hormones. So people with hypothyroidism generally have high TSH and low T4 levels.
Hypothyroidism is treated with a daily dose of synthetic thyroid hormone to replace the hormone they are lacking. This alleviates symptoms over time. Frequent blood tests may be needed initially to adjust the medication dosage. Thereafter, testing is done periodically -- often yearly -- to be sure the dosage is still appropriate.
Warnings and Precautions
If your teen experiences any signs or symptoms that may indicate low thyroid function, make an appointment to see a healthcare provider to determine the cause of your youngster's symptoms.
Teens being treated for hypothyroidism should see their doctor if their symptoms are not improving or are getting worse. Receiving too much thyroid medication may also cause problems, including chest pain, an irregular heartbeat or weight loss -- and possibly even long-term problems, such as osteoporosis. Different brands of thyroid medications sometimes work differently, so check with your teen's doctor if the pharmacy changes the medication brand.
Reviewed by: Mary D. Daley, M.D.