What is hypothyroidism in children?
Hypothyroidism in children is a condition in which the thyroid gland, located in the front of the neck, does not produce enough thyroid hormones, which control general metabolism and many bodily functions. Hypothyroidism in children can have several causes, including an autoimmune disorder (Hashimoto’s disease), in which the body’s immune system mistakenly destroys its own thyroid gland.
In teens, this is perhaps the most common cause of an underactive thyroid, compared to other causes of the condition. Other causes can be certain medications or pituitary hypothyroidism, in which the pituitary gland, which controls the thyroid gland. Sometimes a cause cannot be identified.
While the condition usually develops in adult life, its incidence increases with age, congenital hypothyroidism can occur in children and even newborns.
Children with undiagnosed hypothyroidism in children may experience a slower growth rate.
Additional symptoms include sluggishness, paleness, dry and itchy scalp, increased sensitivity to cold, and constipation. If left untreated, the condition can have devastating effects, including stunting and mental retardation.
Types of hypothyroidism in children
There are several different types of hypothyroidism in children, including:
Congenital hypothyroidism (CH) occurs when the thyroid gland does not develop or function normally before birth. It is a very common problem that affects approximately 1 in 2,500 to 3,000 babies.
Several factors, including family history, your child’s physical exam, your baby’s point of hypothyroidism at the time of diagnosis, and the course of treatment during the first two to three years of life, will help your child’s doctor determine if the cause is hereditary (runs in the family) and if lifelong therapy is required.
Acquired hypothyroidism is most often caused by an autoimmune disorder called chronic lymphocytic thyroiditis (CLT). In this disorder, your child’s immune system attacks the thyroid gland, causing damage and decreased function. The disorder was originally described by the Japanese physician Hakaru Hashimoto and is therefore often referred to by its name – Hashimoto’s thyroiditis.
CLT is more common in girls than boys and adolescents more than preteens. Patients with other forms of autoimmune disease, most commonly insulin-dependent diabetes, are at increased risk of developing CLT. In general, about 20 to 30 percent of diabetics will develop CLT. Because of this, yearly CLT screening is a routine part of diabetes care.
Iatrogenic hypothyroidism is a procedure of acquired hypothyroidism that happens in children who have had their thyroid gland removed (destroyed) or surgically removed. By eliminating the thyroid gland, the body no longer produces thyroid hormone, important to iatrogenic hypothyroidism.
Central hypothyroidism occurs when the brain does not produce thyroid-stimulating hormone (TSH), the signal that tells the thyroid gland to work. This condition is much less common than disorders associated with an abnormal thyroid gland. In fact, in central hypothyroidism, most patients have a common thyroid.
In addition to low TSH, central hypothyroidism can be associated with deficiencies of other hormones, including:
- Growth hormone
- Adrenocorticotropic hormone, which stimulates the adrenal gland during stress
- Luteinizing and follicle-stimulating hormone, which controls the function of the ovaries and testes
- Prolactin, which helps females make milk
- Oxytocin, which is important for labor and breastfeeding
- Antidiuretic hormone, which controls urine production
Central hypothyroidism can occur due to abnormal development of the hypothalamus or pituitary glands (the location in the brain where TSH is produced), trauma, a tumor, or treatment for a tumor (i.e., surgery, radiation). Central hypothyroidism can be inherited, and boys and girls are affected equally.
Causes of hypothyroidism in children
The utmost communal cause of hypothyroidism in children is a family history of the disease. Children whose parents, grandparents, or siblings have hypothyroidism are at increased risk for thyroid disease. This is also true if there is a family history of immune problems affecting the thyroid.
Autoimmune diseases, such as Graves’ disease or Hashimoto’s thyroiditis, appear most often during puberty. These thyroid conditions affect girls more often than boys.
Other common causes of hypothyroidism in children include:
- Not enough iodine in a child’s diet
- Born with a non-functional thyroid or thyroid gland (also called congenital hypothyroidism)
- Inadequate treatment of the mother’s thyroid disease
- Abnormal pituitary gland
Symptoms of hypothyroidism in children
The symptoms of hypothyroidism in children are usually subtle and gradual and may resemble other conditions or medical problems. Many symptoms are non-specific and can be ignored as a normal part of our daily life. Because of this, the condition can go unnoticed for years.
Symptoms can include:
- Fatigue and/or exercise intolerance
- Slower reaction time (a major problem for drivers)
- Weight gain
- Sparse, coarse, and dry hair
- Rough, dry, and thickened skin
- Slow pulse
- Intolerance to cold
- Muscle cramps
- The sides of the eyebrows become thin or droopy
- Boring facial expression
- Speak slowly
- Droopy eyelids
- Puffy and puffy face
- An enlarged thyroid, which produces a goiter-like growth on the neck.
- Increased menstrual flow and cramps in girls and young women.
If you have concerns about your child’s health, talk to your child’s doctor.
A child is at risk for hypothyroidism in children if they have any of these:
- A chromosomal illness such as Downcast syndrome, Williams syndrome, or Turner syndrome
- An autoimmune disorder such as type 1 diabetes or celiac disease
- Insufficient or excessive intake of iodine
- Injury to the thyroid gland
- Radiation to the head and neck
Diagnosis of hypothyroidism in children
Over-all, your physician may perform an underactive thyroid test if you feel increasingly tired, have dry skin, constipation, and weight gain, or have had earlier thyroid problems or goiter.
The diagnosis of hypothyroidism in children is based on your symptoms and the results of blood tests that portion the level of TSH and occasionally the level of the thyroid hormone thyroxine. A low thyroxine level and a high TSH level indicate an underactive thyroid. That’s because your pituitary makes more TSH stimulate your thyroid gland to make more thyroid hormone.
Physicians can diagnose thyroid disorders much earlier than in the past, often previously you experience symptoms. Because the TSH test is the best screening test, your doctor will likely check your TSH first and then perform a thyroid hormone test if necessary.
TSH tests also play an important role in the management of hypothyroidism. They help your doctor determine the correct dose of medicine, both initially and over time.
Additionally, TSH tests are used to help diagnose a condition called subclinical hypothyroidism, which usually does not cause outward signs or symptoms. In this condition, you have normal blood levels of triiodothyronine and thyroxine, but higher levels of TSH than normal.
There are assured aspects that can affect blood tests for thyroid problems. One is blood-thinning medicine called heparin. Another is biotin, a vitamin that is taken as a stand-alone supplement or as part of a multivitamin. Tell your doctor about any medications or supplements you are taking before blood tests are done.
Treatment for hypothyroidism in children
Ordinary treatment for hypothyroidism in children involves day-to-day use of the synthetic thyroid hormone levothyroxine (Levo-T, Synthroid, others). This oral medication restores proper hormone levels, reversing the signs and symptoms of hypothyroidism.
You will likely start to feel better shortly after starting treatment. The drug gradually reduces the cholesterol levels raised by the disease and can reverse any weight gain. Levothyroxine treatment will likely be lifelong, but because the dose you need may change, your doctor will likely monitor your TSH level every year.
Determining the right dose can take time
To determine the correct dose of levothyroxine initially, your doctor usually checks your TSH level after six to eight weeks. After that, blood levels are usually checked six months later. Excess amounts of the hormone can cause side effects, such as:
- Increased appetite
- Heart palpitations
If you have coronary artery disease or severe hypothyroidism, your doctor may start treatment with a smaller amount of medicine and gradually increase the dose. Progressive hormone replacement allows your heart to adjust to increased metabolism.
Levothyroxine has virtually no side effects when used in the proper dosage and is relatively inexpensive. If you change brands, tell your doctor to make sure you keep getting the correct dose.
Also, do not skip doses or stop taking the medicine because you feel better. If you do, the symptoms of hypothyroidism will slowly return.
Adequate absorption of levothyroxine
Certain medications, supplements, and even some foods can affect your ability to absorb levothyroxine. Talk to your doctor if you consume large amounts of soy products or a high-fiber diet, or if you take other medications, such as:
- Iron supplements or multivitamins that contain iron
- Aluminum hydroxide, found in some antacids
- Calcium supplements
It is best to take levothyroxine on an empty stomach at the same time each day. Ideally, you will take the hormone in the morning and wait an hour before eating or taking other medications. If you take it at sleep time, wait four hours after your last meal or snack.
If you forget to take a dose of levothyroxine, take two pills the next day.
If you have subclinical hypothyroidism, talk to your doctor about treatment. For a comparatively mild increase in TSH, you probably won’t benefit from thyroid hormone therapy, and treatment could even be harmful. On the other hand, for a higher TSH level, thyroid hormones can improve your cholesterol level, your heart’s pumping ability, and your energy level.
Hypothyroidism in children cannot be prevented. The best way to prevent developing a serious form of the condition or having symptoms seriously affect your life is to watch for signs of hypothyroidism. If you experience any of the symptoms of hypothyroidism, the best thing to do is talk to your healthcare provider. Hypothyroidism is very manageable if you catch it early and start treatment.