Hyperthyroidism means overactivity of the thyroid gland, resulting in too much thyroid hormone in the bloodstream.
The oversecretion of thyroid hormones leads to overactivity of the body's metabolism. In newborns, the most common cause of an overactive thyroid is called neonatal Graves' disease, which can be life threatening. However, hyperthyroidism occurs more often in children and adolescents than in newborns.
Newborn hyperthyroidism results when the mother has or has had Graves' disease herself. Graves' disease in adults is an autoimmune disorder characterized by the production of antibodies that stimulate the thyroid gland. When a pregnant woman has these antibodies, they can cross the placenta and affect the fetus' thyroid gland. Graves' disease in pregnant woman can result in stillbirth, miscarriage, or premature birth.
The following are the most common symptoms of hyperthyroidism in a newborn. However, each baby may experience symptoms differently. Symptoms may include:
Low birth weight
Small or abnormally shaped head
Poor weight gain (failure to thrive)
Enlarged liver and spleen
Fast heartbeat (which can lead to heart failure)
High blood pressure
Difficulty breathing due to enlarged thyroid gland (goiter) pressing on the windpipe
Prolonged exposure to high levels of thyroid-stimulating hormone (characteristic of hyperthyroidism) can pose serious health problems to a child, including the following:
Premature closing of bones in the skull (fontanelles)
Rapid growth that slows and ultimately stops at short stature
The symptoms of hyperthyroidism may resemble other conditions or medical problems. Always consult your child's doctor for a diagnosis.
If not diagnosed shortly after birth, hyperthyroidism in the newborn can be fatal. In addition to a complete medical history and physical exam, diagnostic procedures for hyperthyroidism may include measurement of thyroid hormone in the bloodstream.
With prompt treatment, babies usually recover completely within a few weeks. However, hyperthyroidism may recur during the first 6 months to 1 year of life. The goal of treatment is to restore the thyroid gland to normal function, producing normal levels of thyroid hormone.
Treatment may include:
Medication that blocks the production of thyroid hormones and treats rapid heart rate
Treatment for heart failure