Abundant information concerning thyroid problems in adults is available on the internet and in books. However, child-specific, validated information about thyroid conditions is less commonly found in the public domain. In addition, an ongoing challenge exists in discerning the quality of available thyroid information. The expert advice of a licensed, board certified medical specialist such as a pediatric endocrinologist is often needed to help determine advice that is valid, scientifically tested from all other recommendations.
I see a sizeable number of children and teens in my practice with diagnosed thyroid problems. I also care for a number of patients whose parents or doctors have referred to me for concerns about the possibility of thyroid disease. A large block of the time I spend with these children and their families during clinic visits involves education about the thyroid gland and its importance on childhood health.
I’d like to help those who might be in search of credible information on this topic by sharing basic, sound medical facts and data that I believe can be of good use to parents or caregivers in better understanding thyroid function and problems in children.
What is the thyroid gland and what does it do?
The thyroid is a small, butterfly-shaped gland, weighing less than an ounce in an adult. It is located in the lower, middle, front part of the neck and is regulated by the small, pituitary gland located deep within the brain. The thyroid’s main function is to produce thyroid hormone which consists of a combination of protein and the mineral iodine. This super hormone acts very deeply within the body binding onto the DNA in cells throughout to regulate metabolism, growth and body temperature. The thyroid has a stronghold on how the body uses energy and can speed up or slow down your metabolism.
The metabolic effects of thyroid hormone are multiplied in children. It is an essential partner of growth hormone in aiding height growth in children and serves a vital role in regulating the start and progress of puberty. Too little or too much of this essential hormone released into the body can wreak havoc causing serious negative effects on the health of a child. The two main types of thyroid disease are called hypothyroidism and hyperthyroidism.
What is hypothyroidism and what causes it?
Hypothyroidism is a lack of enough thyroid hormone production. A number of problems occur with lack of thyroid hormone and the symptoms and their severity correlate to the level at which production has been depleted.
A big divide, based on age, exists in what is the underlying cause of hypothyroidism. Congenital hypothyroidism refers to a specific type that is diagnosed in newborn infants in the first one to two months of life. This serious condition occurs in roughly 1 in every 4,000 newborn babies and can have devastating effects if not detected and treated within the first 2-3 weeks after birth. A hypothyroid infant is unusually quiet and inactive, with poor appetite and sleeps for excessively long periods. In the past, the consequences of untreated congenital hypothyroidism developed into lifelong mental retardation. Thankfully, state mandated newborn screening programs that began in the 1970s now routinely test the blood of all newborns for evidence of congenital hypothyroidism as well as other metabolic diseases. As long as this test is administered, there is little risk of missing its presence.
Acquired hypothyroidism refers to hypothyroidism that begins anytime after the newborn period which encompasses the first six months of life. Whereas the expected number of infants born each year with congenital hypothyroidism is well-known worldwide, the expected numbers of children and teens with hypothyroidism is not well known as symptoms are often misdiagnosed. It certainly seems the case when the most recent study that attempted to determine the number of children and teens with hypothyroidism showed the number at less than 1%.
Iodine is an important mineral in the production of thyroid hormone. Lack of dietary iodine remains a cause of this malady around the globe. In the U.S. and many parts of the world, fortification of salt and foods with iodine has made this deficiency a very unlikely cause of hypothyroidism. The most common reason for its occurrence in the U.S. is autoimmune thyroid disease (also known as Hashimoto disease). This condition is still a mystery in terms of what causes the body’s immune system to attack its thyroid gland. We do know that it runs in families with links to certain inherited genes increasing the risk of passing it on to future generations. In addition, triggers such as infections, stress, or pregnancy might activate this condition in susceptible people. In children, it tends to occur in girls more often than boys, and the peak in occurrence is in the mid-teenage years.
While it is rare, problems can occur when the pituitary gland leads the thyroid astray. This improper regulation of thyroid function can cause a subtle form of hypothyroidism known as central hypothyroidism.
What are symptoms of hypothyroidism and how is it diagnosed?
It is important to understand that a correct diagnosis of hypothyroidism should be made by exploring both physical symptoms as well as through targeted blood testing. As a pediatric endocrinologist at Cook Children’s, I focus heavily on the impacting that thyroid hormone has on a child’s growth as a key finding. Weight gain does occur in hypothyroidism, but very rarely leads to severe levels of obesity. Some of the more common symptoms of hypothyroidism are summarized in the table below.
- Short stature and/or abnormally slow height growth
Overweight, weight gain
- Dry skin
- Cold intolerance – feeling cold all the time
- Enlargement of the thyroid gland (goiter)
- Fatigue, excessive sleepiness
- Problems with puberty
- Delayed puberty
- No menstrual periods or irregular menstrual periods in girls
- Early puberty (rare)
Blood test measures of thyroid hormone (known as T4 or free T4) and the pituitary hormone thyroid stimulating hormone (known as TSH) assist in the diagnosis of hypothyroidism. The cardinal finding on blood testing is a high TSH and low thyroid hormone. An ultrasound of the thyroid gland as well as special nuclear medicine scans is sometimes quite helpful in both making the diagnosis and determining an underlying cause of hypothyroidism.
What is hyperthyroidism and what causes it?
Hyperthyroidism, by contrast, is a condition where too much thyroid hormone is released into the body upsetting the balance of the metabolism and causing devastating effects on well being. Thankfully, this condition is rare in children, occurring in less than 1 percent. In its early stages, symptoms may be subtle so unfortunately many children are in advanced stages upon diagnosis. Hyperthryoidism in its most severe form can be life-threatening.
The most common cause of hyperthyroidism is Graves’ disease which is an autoimmune condition similar to autoimmune thyroid disease with the exception that the immune system is stimulating the thyroid to over-produce thyroid hormone. This condition remains a mystery as well to the medical world in terms of what causes it to happen. We do know that like autoimmune thyroid disease, it does run in families.
What are symptoms of hyperthyroidism and how is it diagnosed?
Because of the seriousness of hyperthyroidism, rapid recognition is important. Exophthalmos (bulging of the eyes), a condition affecting the late actor Marty Feldman, is the most recognized physical sign of Graves’ disease. Some of the more common symptoms of hyperthyroidism are summarized in the table below.
- Weight loss
- Increased appetite
- Heat intolerance – feeling hot all the time
- Fatigue, muscle tiredness
- Enlargement of the thyroid (goiter)
- Rapid heart rate, high blood pressure
- Excessive sweating
- Tremor (shakiness) in hands
- Irritability, problems concentrating
- Poor school performance
- Bulging eyes
- Irregular menstrual periods in girls
Blood test measures of thyroid hormone (known as T4 or free T4) and the pituitary hormone thyroid stimulating hormone (known as TSH) assist in the diagnosis of hyperthyroidism. Converse to hypothyroidism, we expect to find blood testing measures with a very low TSH and high thyroid hormone level. A nuclear medicine scan is often times very useful in evaluation of cases of hyperthyroidism. Additionally, an ultrasound test might be prescribed.
How are hypothyroidism and hyperthyroidism treated?
Treatment of hypothyroidism requires daily tablets of thyroid hormone (levothyroxine, synthroid, levoxyl, and levothroid) combined with scheduled return visits to see the pediatric endocrinologist who will monitor progress via physical exam and blood testing. Congenital hypothyroidism is permanent and requires lifelong treatment whereas acquired hypothyroidism, however, is not always permanent.
Treatment of hyperthyroidism is far more complex than the treatment of hypothyroidism and involves the use of a thyroid suppressing medication in the early phase of therapy. Due to the long-term mixed outlook for a cure of Graves’ disease, many sufferers must have their thyroid destroyed either by radioactive iodine treatment or surgical removal. Once the thyroid is destroyed, these individuals must remain on lifelong thyroid replacement like those with hypothyroidism.
It is my hope that by sharing some important medical facts and data you have been enlightened about this powerful gland. Furthermore, I hope it will enable parents and caregivers to recognize symptoms of a possible thyroid condition in a child and better understand the proper treatment plan.