Thyroid Disorders in Children

The thyroid is a small butterfly-shaped gland that sits in front of the windpipe in the neck. The thyroid produces hormones that help regulate body temperature, metabolism, growth, and development. In children and adolescents, having an adequate amount of thyroid hormone is essential to brain development. Thus, parents need to be aware of the symptoms of both overactive thyroid (hyperthyroidism) and underactive thyroid (hypothyroidism).

Hypothyroidism

Hypothyroidism occurs when the thyroid does not produce enough thyroid hormone. The symptoms of hypothyroidism will vary depending on how severe your child's hormone deficiency is. However, in general, symptoms will develop slowly over time.

Symptoms of hypothyroidism include increased sensitivity to cold, dry skin, puffy face, muscle weakness and pain, impaired memory, fatigue, weight gain, a slowed heart rate, constipation, depression, and pain, swelling, and stiffness in the joints. Female adolescents who have begun menstruating may also have heavier menstrual periods than usual or irregular menstrual cycles. Children with hypothyroidism may also experience a delay in the development of permanent teeth, poor mental development, short stature resulting from poor growth, and a delay in the onset of puberty.

Infants can be born with hypothyroidism. Initially, no signs or symptoms may occur. However, over time, an infant with hypothyroidism may have a large, protruding tongue, yellowing of the whites of the eyes and skin (jaundice), frequent choking, and a puffy face.

The symptoms of hypothyroidism get worse if the condition is left untreated. Additionally, several complications may occur because of untreated hypothyroidism. The constant stimulation of the thyroid gland to produce thyroid hormone may lead to the gland becoming enlarged, a condition known as goiter. Goiter can be uncomfortable, affect one's appearance, and interfere with swallowing and breathing. Slowed mental functioning is another possible complication of an underactive thyroid. Additionally, long-term unmanaged hypothyroidism may lead to peripheral nerve damage and infertility.

Though rare, myxedema, a life-threatening condition, can occur due to long-term undiagnosed hypothyroidism. Symptoms of myxedema include extreme intolerance to cold and drowsiness followed by lethargy and unconsciousness. A myxedema coma can be triggered by infection, sedatives, or other stress to the body. If your child is experiencing symptoms of myxedema, take her to the emergency room immediately.

Hypothyroidism has several potential causes. The most common cause of hypothyroidism is an autoimmune disorder called Hashimoto's thyroiditis. In an autoimmune disorder, the immune system produces antibodies that attack the body's tissues. Scientists are not sure why this occurs. Radiation therapy used to treat cancers of the head and neck may affect the thyroid gland, resulting in an underactive thyroid.

Additionally, treatment for hyperthyroidism can result in hypothyroidism. Many times radioactive iodine therapy or anti-thyroid medication is utilized to treat an overactive thyroid. However, these treatments can sometimes result in permanent hypothyroidism.

Some medication can also contribute to an underactive thyroid. For instance, lithium, a medication used in the treatment of some psychiatric disorders, can lead to hypothyroidism. A pituitary disorder in which the pituitary gland fails to produce enough thyroid-stimulating hormone can also cause hypothyroidism.

Some infants are born with a defective or no thyroid gland. In many cases, the thyroid gland failed to develop normally for unknown reasons. Oftentimes, infants born with congenital hypothyroidism initially have no symptoms.

Certain children may be at risk for developing hypothyroidism. Children with autoimmune diseases or with a family history of hypothyroidism are at greater risk of developing the condition. Children who have received radiation to the head, neck, or upper chest may also be at higher risk of developing the condition.

If your child experiences the symptoms of hypothyroidism, talk with your pediatrician. Your pediatrician will go over your child's medical history and do a blood test to measure your child's thyroid stimulating hormone level. Your child's thyroxine (T4) level may also be tested. A diagnosis of hypothyroidism is made when your child's thyroid stimulating hormone level is high and thyroxine level is low.

The standard treatment for hypothyroidism is a daily medication called levothyroxine. Your pediatrician may also refer you to a pediatric endocrinologist to help manage your child's condition. Regular blood tests will need to be done in order to measure your child's thyroid stimulating hormone, and adjustments to medication will be made when necessary.

Hyperthyroidism

Hyperthyroidism occurs when the thyroid produces too much thyroid hormone. Symptoms of this condition include weight loss, increased appetite, tremor, or trembling in the hands and fingers, fatigue, brittle hair, muscle weakness, goiter (an enlarged thyroid gland), heat sensitivity, sweating, skin thinning, and changes in bowel movement patterns, especially having more bowel movement than usual. Additionally, girls who have begun menstruating may experience irregular menstrual cycles. Your child may also have a rapid heartbeat (tachycardia), sensations of a pounding heart (palpitations), or an irregular heartbeat (arrhythmia).

Though uncommon, a condition called Graves' ophthalmopathy may also occur with hyperthyroidism. Signs of Graves' ophthalmopathy include bulging eyeballs, excessive tearing or discomfort in one or both eyes, swollen or red eyes, and light sensitivity, double vision, inflammation, blurry vision, or reduced eye movement.

Untreated hyperthyroidism can lead to serious complications. For instance, arterial fibrillation and congestive heart failure may occur. Both conditions are typically reversible with appropriate treatment. Another possible complication of hyperthyroidism is brittle bones (osteoporosis).

Thyrotoxic crisis, also called thyroid storm, is a life-threatening condition that can occur because of unmanaged hyperthyroidism. Signs of the thyrotoxic crisis include rapid heartbeat, high fever, shaking, agitation, persistent sweating, diarrhea, confusion, and unconsciousness. If your child has any of these symptoms, seek immediate medical attention.

Graves' disease is the most common cause of hyperthyroidism. Grave's disease is an autoimmune condition in which antibodies produced by the immune system cause the thyroid to produce too much thyroxine. Scientists are not sure what causes Graves' disease.

A toxic adenoma or Plummer's disease can also be responsible for causing hyperthyroidism. An adenoma is part of the thyroid gland that has walled itself off from the rest of the gland, forming benign (noncancerous) tumors. Some adenomas produce too much thyroxine, but it is not known why this occurs.

If your child has symptoms of hyperthyroidism, talk with your pediatrician. Your pediatrician will go over your child's medical and family history with you. Your pediatrician may also order a blood test to measure the levels of thyroxine and thyroid stimulating hormone in your child's blood. A diagnosis of hyperthyroidism is made when the thyroxine level is high and thyroid-stimulating hormone is low or nonexistent.

Your pediatrician may also order a radioiodine reuptake test. For this test, your child will take a small dose of radioactive iodine. Over time, the iodine gathers in the thyroid gland because the thyroid utilizes iodine to produce hormones. After two, six, or 24 hours, your child's thyroid will be checked to determine how much iodine the thyroid gland has absorbed. A high uptake of iodine means that the thyroid gland is making too much thyroxine, and a diagnosis of hyperthyroidism can be made.

Hyperthyroidism can be treated with a daily medication called methimazole. This medication prevents the thyroid from producing excess thyroxine. Symptoms of hyperthyroidism typically improve within six to 12 weeks on this medication. Your child will need to have periodic blood tests to measure his thyroid levels, and medication adjustments will be made, if necessary.

Another treatment option for hyperthyroidism is radioactive iodine. Radioactive iodine taken orally is absorbed by the thyroid, causes the gland to shrink, and reduces the symptoms of hyperthyroidism. Symptoms usually improve within three to six months with this treatment. Radioactive iodine can lead to hypothyroidism, and your child may need to take thyroid replacement medication as a result.

Thyroid disease in children needs to be taken seriously, as it can interfere with a child's development. If your child has symptoms of hypothyroidism or hyperthyroidism, please talk with your child's pediatrician.