Diagnosing Graves' Disease in Children
Graves' disease is an autoimmune condition that causes hyperthyroidism, also known as an overactive thyroid, in children. That means the child’s own immune system attacks the thyroid, a small, butterfly-shaped gland located in the front of the neck that makes two hormones—thyroxine (also known as T4) and triiodothyronine (also known as T3). These hormones help the body transform food into energy, a process known as metabolism. They also play a role in regulating a child's growth, development, and body temperature.
Usually, a hormone made in the pituitary gland called thyroid-stimulating hormone (TSH) acts as a sensor that tells the thyroid to make more T3 and T4 when levels are running low. For unknown reasons, children with Graves' disease develop antibodies that mimic the activity of TSH. These antibodies, called thyroid-stimulating immunoglobulins, attach themselves to the thyroid, sending a false signal that instructs the thyroid to produce too much T3 and T4.
Many children with Graves' disease have a family history of the condition. The disease is more common in girls and in children with other autoimmune disorders, such as lupus, type 1 diabetes, and celiac disease. The condition can arise at any point during childhood but is most likely to begin in adolescence.
Endocrinologists at Hassenfeld Children’s Hospital of New York at NYU Langone—specialists in treating conditions involving endocrine glands, such as the thyroid, and the hormones they produce—consider a number of factors when diagnosing Graves’ disease.
Signs and Symptoms
Overproduction of thyroid hormones can cause an enlargement of the thyroid, called goiter, which makes the gland visible in the neck. It can also affect the eyes, causing bulging, light sensitivity, and irritation. Teenage girls may have lighter and less frequent menstrual periods.
Hyperthyroidism causes the metabolism to speed up, which can lead to other, sometimes serious, conditions. Children with Graves' disease may have high blood pressure, or hypertension; a rapid or irregular heartbeat, also known as arrhythmia; and a tremor, or shakiness, in the hands. They often lose weight, despite being hungry and eating more than usual, and have more frequent bowel movements or diarrhea. Many children with this condition have increased sensitivity to heat, causing excess sweating. They may also have difficulty concentrating, restlessness, fatigue, or anxiety, which can sometimes be mistaken for conditions such as attention deficit hyperactivity disorder or anxiety disorders. Over time, rapid metabolism caused by Graves' disease can lead to growth problems.
Our specialists use the following tests to make a diagnosis.
During a physical exam, your child's doctor looks for visible signs of Graves' disease, such as an enlarged thyroid or bulging eyes. The doctor reviews your child’s growth chart and medical history to determine whether there has been significant weight loss or growth problems. The doctor asks you or your child about other symptoms, such as restlessness or anxiety, difficulty concentrating, heat sensitivity, or irregular menstrual periods, and may use a blood pressure cuff to check your child's blood pressure.
The doctor may order blood tests to measure the levels of the thyroid hormones, T3 and T4, which are elevated in children with Graves' disease. Blood tests are also used to measure TSH, which is lower than usual in children with this condition. Another blood test, which measures thyroid-stimulating immunoglobulin antibodies, can help in confirming the diagnosis.
If the doctor finds that one side of your child's thyroid is bigger than the other or that its texture is uneven, the doctor may recommend a thyroid ultrasound. By using sound waves to obtain a picture of the gland, ultrasound can help to identify other causes of hyperthyroidism, such as a cyst or other growths.
Radioactive Iodine Uptake Test
To confirm a diagnosis of Graves' disease, the doctor performs a radioactive iodine uptake test. Iodine is an element that helps the thyroid make hormones, and this test measures how much iodine is absorbed by the thyroid. First, your child swallows a liquid or capsule that contains a small amount of radioactive iodine. Several hours later, your child’s doctor places a scanner called a gamma probe over your child's neck to find out how much iodine has been absorbed by the thyroid. A thyroid that absorbs a higher-than-usual amount of iodine is overactive—that is, it's making too much thyroid hormone.