An underactive thyroid gland causes reduced production and secretion of the thyroid hormone, which leads to a condition known as hypothyroidism. When a deficiency of thyroid hormones is present in a newborn baby at birth, it is referred to as congenital hypothyroidism. The condition can occur due to improper location of the thyroid gland, inherited, passed on from a mother suffering from Hashimoto’s disease, deficiency of the pituitary hormone, etc.
What Is the Thyroid Gland?
The thyroid is a small endocrine gland that plays a crucial role in the body. The gland comprises two lobes bridged by a band of tissues known as the isthmus. Both lobes are present on either side of the trachea (windpipe). The main function of the thyroid gland is the production and secretion of thyroid hormones (thyroxine- T4, triiodothyronine-T3, and calcitonin). These hormones are crucial for the regulation of some important functions of the body, like metabolism, development of the brain, growth of the body, etc.
What Is Hypothyroidism?
Hypothyroidism is a thyroid gland disorder where the gland does not produce enough thyroid hormone, resulting in several problems. This condition is also called underactive or low thyroid, and it is the second most common thyroid gland disorder. Symptoms of hypothyroidism are often unnoticeable for a long time; therefore, the condition is usually diagnosed late. Some of the most common symptoms of hypothyroidism are unusual weight gain, feeling extremely tired, pain in muscles and joints, thinning of hair, hoarse voice, depression, etc. In addition, babies with hypothyroidism may be asymptomatic or show very different symptoms than adults.
What Is Congenital Hypothyroidism?
Congenital hypothyroidism is defined as thyroid hormone deficiency present at birth. Babies with congenital hypothyroidism have an underactive thyroid gland; or complete absence of the thyroid gland. Since thyroid hormone is crucial for brain development and overall growth, children can develop developmental disabilities and growth failure if they are left untreated.
What Causes Congenital Hypothyroidism?
Congenital hypothyroidism occurs when the thyroid gland does not develop properly; it can be missing or very small. Sometimes it ends up being in the wrong part of the neck. Following are the most common causes of congenital hypothyroidism:
A thyroid gland in an abnormal location ( ectopic thyroid gland); An underdeveloped thyroid gland ( thyroid hypoplasia); Absence of a thyroid gland (thyroid agenesis), all three of these thyroid abnormalities are known as thyroid dysgenesis. These are considered to be prevalent causes of congenital hypothyroidism. Thyroid dysgenesis is not inherited from parents to offspring.
Another cause of congenital hypothyroidism is the inability of the gland to produce an adequate amount of thyroid hormones. This condition is inherited and has a 25% prevalence rate in children.
Mothers suffering from Hashimoto’s thyroiditis may pass blocking antibodies to their children in the womb. This type of congenital hypothyroidism is often temporary.
Mothers suffering from Grave’s disease might take antithyroid medication during pregnancy; this drug can cross the placental barrier and affect the baby.
Pituitary hormone deficiency may cause a lack of thyroid-stimulating hormone, which causes thyroid hormone deficiency and, eventually, hypothyroidism in babies.
What Are the Symptoms of Congenital Hypothyroidism?
Initially, the signs and symptoms of congenital hypothyroidism are not very obvious. Therefore, neonatal screening is essential because of the lack of clear signs during the first few weeks after birth. However, when congenital hypothyroidism is severe, the baby may show the following signs and symptoms:
Swollen and puffy face.
Large and thick tongue.
More significant than usual soft spots on the head.
Poor muscle strength.
Distended stomach with outpouching of the belly button.
How Is Congenital Hypothyroidism Diagnosed?
Babies in most developed countries undergo a standard newborn screening program. A heel-prick blood sample is collected and sent to the laboratory to check for abnormalities. Most cases of congenital hypothyroidism are diagnosed during these screenings.
Blood samples collected during the first few days after birth are evaluated in the laboratory, and the blood level of the following hormones are checked:
T4 or Thyroxine.
A low level of thyroxine and elevated thyroid-stimulating hormone suggests congenital hypothyroidism. To further confirm this diagnosis, another blood sample is collected, but this time from the vein, to check the level of free T4 in the blood. Again, a low level of free T4 and an elevated level of the thyroid-stimulating hormone will confirm the diagnosis of congenital hypothyroidism in the baby.
The doctor might suggest imaging tests like ultrasound or a thyroid scan, apart from blood tests. These tests are done to determine the thyroid gland’s size and location and to check if the thyroid gland is altogether missing.
How Is Congenital Hypothyroidism Treated?
The treatment of congenital hypothyroidism involves:
Thyroid Hormone Replacement: Replacement of the missing thyroid hormone with synthetic or laboratory-made thyroid hormones to restore the normal levels of the hormone in the blood. The most common form of thyroid hormone used in the treatment is Levothyroxine. It is identical to the T4 hormone produced by the body. Currently, these are available in tablet form to be given orally to the baby. It can be mixed with water, milk, or formula and given to the baby. It is made available in the pharmacy even with an online prescription. The treatment starts as soon as the baby is born, and in most cases, the child is required to take medicine lifelong. The parents must give thyroid hormone daily to the baby to maintain a steady blood level.
Monitoring Blood Hormone Level: A vital part of the treatment is the regular monitoring of blood thyroid hormone levels; this monitoring is essential to make sure that the amount of medication is adjusted from time to time to keep up with the baby’s growth. Generally, the blood tests are done every one to two months for six months and then every two to three months after that.
Is Lifelong Treatment Necessary?
Generally, thyroid hormone replacement therapy is a lifelong treatment modality. With proper treatment and timely adjusted doses, these children can grow up to be healthy and normal. However, in cases where congenital hypothyroidism is transient or temporary, thyroid hormone therapy is advised for the first three years of life.
Congenital hypothyroidism is a severe disorder of the thyroid gland, and it can cause growth and developmental issues in the baby. However, with the help of an expert endocrinologist, this condition can be treated and managed. Often, the child suffering from congenital hypothyroidism has to take hormone replacement therapy throughout their life.