Congenital Hypothyroidism (Cretinism) in Children: Causes, Symptoms, and Management.

Introduction:

Congenital hypothyroidism, formerly known as cretinism, is a severe thyroid hormone deficiency in infants. It results in stunted growth, brain dysfunction, and physical abnormalities. A thyroid gland issue in the unborn child or a deficiency in iodine in the mother's body during pregnancy could possibly be the reason for the disease. Iodine is required by a baby's body to produce thyroid hormones. These hormones are necessary for the normal development of the nervous system and the brain and healthy growth.

Congenital hypothyroidism became uncommon in the United States and the rest of the Western world once iodized salt was introduced in the early 20th century. But severe iodine shortage is still widespread in underdeveloped countries leading to the disease.

What Is a Thyroid?

The thyroid is a small gland located beneath the skin and muscles in the front of the neck above the collarbone. It is brownish-red in color, and its left and right portions (called lobes) resemble butterfly wings. It weighs less than an ounce yet aids in various bodily functions, including obtaining energy from meals, growth, and aids in sexual development.

What Is Congenital Hypothyroidism?

Hypothyroidism develops when the thyroid gland fails to produce enough thyroid hormone. Congenital hypothyroidism is when a newborn is born with the disease. It can lead to major health complications if left untreated. The thyroid gland is placed directly below the voice box in the neck. This gland produces thyroid hormones. These hormones regulate the metabolic rate, which could possibly be the reason. Thyroid hormones maintain a healthy metabolic rate. This improves the functioning of the brain, heart, muscles, and other organs. A healthy metabolism also ensures a good body temperature, heart rate, energy level, and rate of growth. If a baby does not produce enough thyroid hormones, it can lead to major issues such as mental retardation, growth delays, and hearing loss. These issues must be treated as soon as possible to reduce the likelihood of these long-term complications.

What Causes Congenital Hypothyroidism?

• Various factors can result in congenital hypothyroidism. Only some of the causes of congenital hypothyroidism are hereditary.

• The most prevalent cause is a deficiency of iodine in the mother's diet in the affected infants. Iodine is necessary for the production of thyroid hormones.

• 15 to 20 percent of cases of congenital hypothyroidism have genetic origins.

Congenital hypothyroidism's most common causes are:

• A thyroid gland that is positioned improperly (ectopic thyroid gland).

• Reduced thyroid function (thyroid hypoplasia).

• Absence of thyroid gland (thyroid agenesis).

• These abnormalities collectively are known as thyroid dysgenesis and typically do not pass down from parents; the likelihood that further children will experience the same issue is relatively low.

• The thyroid may be normal but unable to produce an average amount of thyroid hormone, which is another cause of congenital hypothyroidism. Thyroid dyshormonogenesis is the term for this. A child born that will be born to the same parents in the future has a 25 percent chance (one in four) of inheriting this form of congenital hypothyroidism.

Less Common Causes:

• During pregnancy, a "thyroid-blocking antibody" is transmitted from mother to child. Moms with Hashimoto's thyroiditis may create this "blocking antibody." This type of congenital hypothyroidism is typically transitory, lasting only a few weeks to months.

• Hormonal medications taken by the mother.

• Anti thyroid medication used for hyperthyroidism in Grave’s disease.

• Iodine deficiency during pregnancy can be a cause of congenital hypothyroidism in a child.

• The infant cannot transmit the signal from the brain (pituitary gland) to activate the thyroid. This may be coupled with deficits in other pituitary hormones.

• Additional hormone testing and brain imaging will be conducted depending on the clinical condition to know the exact cause.

What Are the Risk Factors?

The risk factors for congenital hypothyroidism are:

• A chromosomal condition including Down syndrome, Williams syndrome, and Turner syndrome.

• A condition of the immune system, such as diabetes type 1 or celiac disease. This is a disorder characterized by many hormone deficits, including pseudohypoparathyroidism.

• Injury to the thyroid gland.

What Are the Symptoms of Congenital Hypothyroidism?

Newborns with cretinism or congenital hypothyroidism exhibit the following symptoms:

• Lack of weight gain or delayed weight gain.

• Retarded growth.

• Weariness and lethargy.

• Poor feeding.

• Increased facial thickness.

• Abnormal bone development.

• Mental retardation.

• Little cry.

• Constipation.

• Excessive sleep.

• Jaundice.

• Flaccidity and weak muscular tone.

• Hoarse voice.

• Large tongue.

• Cold, dry skin.

• Pale skin.

• Inflammation of the skin (myxedema).

• Neck enlargement caused by an enlarged thyroid gland (goiter).

However, the symptoms may vary with each child, and some newborn babies may not show any signs in the first few months and may start showing symptoms gradually.

How Is Congenital Hypothyroidism Diagnosed?

The diagnosis of congenital hypothyroidism is based on the following:

• Blood Tests: The recommended screening age for congenital hypothyroidism is three days old. Tests are done prior to discharge or within seven days of birth. A few droplets of blood are drawn from the baby's heel for testing. In one of the tests, thyroid function is evaluated. The blood is analyzed for levels of thyroid hormones. In addition, levels of hormones that instruct the thyroid to produce additional hormones are also measured.

• Imaging Tests: The health care professional may also advise the patient to have imaging tests like ultrasonography and scintigraphy.

How Is Congenital Hypothyroidism Treated?

The most common treatment for congenital hypothyroidism in children is the daily administration of synthetic thyroid hormones. The child will likely require these medications for life. In some instances, the thyroid gland may resume functioning. This could occur by three years of age. Blood tests will be performed over time to evaluate the thyroid gland’s functioning. Additionally, the child's growth and development will be monitored over time.

What Are the Possible Complications of Congenital Hypothyroidism?

Average growth and development might be impacted by congenital hypothyroidism. This includes sexual development also. If left untreated, this ailment may also result in the following:

• A disordered walk.

• Muscle stiffness.

• Inability to communicate (mutism).

• Autistic behavior.

• Vision and hearing difficulties.

• Difficulties with memory and focus.

Conclusion:

A child with hypothyroidism will take thyroid hormone to compensate for what the gland cannot produce. Most children must take the medication for the rest of their lives. Some infants are born with transient (temporary) hypothyroidism. This may result from preterm birth, thyroid disorders in the mother, or medications used by the mother during pregnancy. Typically, this kind of hypothyroidism resolves on its own within the first weeks or months of life.