Approach to Congenital Goiter in Newborns and Infants

What Is the Thyroid Gland?

The thyroid is a small organ located underneath the layers of skin and muscles in front of the middle of the neck. The gland is wrapped around the windpipe (trachea). The shape of the gland is of a butterfly with a reddish-brown color. It is made up of two different lobes - the right lobe and the left lobe. Each of them is located on either side of the windpipe and connected by a bridge called the isthmus. It is one of the glands in the body that create and release substances to keep the body functioning normally.

The thyroid gland creates and secretes the hormones in the bloodstream, such as thyroxine (T4) and triiodothyronine (T3). These hormones play an essential role in all body cells functioning normally. The level of each hormone is very important to continue normal body function. For instance, if the thyroid gland releases too much of the thyroid hormones, it causes hyperthyroidism disorder. This speeds up the body's cell activities and causes complications such as increased heart rate or abnormal bowel motions.

On the other hand, if the thyroid hormones are secreted at a lower level by the thyroid gland, it can cause hypothyroidism disorder. In hypothyroidism, the body’s cell activities slow down, and so are the body functions. A person with this disorder may feel the symptoms such as low heart rate and constipation.

What Is Congenital Goiter in Newborns and Infants?

The thyroid hormone plays an essential part in the development of the central nervous system in infants. Sometimes iodine deficiency, iodine exposure, or thyroid disease in the mother can cause complications related to the thyroid gland in a fetus. Congenital goiter is caused by enlargement of the thyroid gland with or without normal thyroid hormone secretion. There are only one in 40,000 cases seen with the nodular or diffuse mass or overgrowth on the head and neck due to this disorder, as the disorder related to the thyroid gland is often seen as hereditary and asymptomatic at the time of birth. Also, the abnormalities related to the thyroid gland are often associated with hyperthyroidism, hypothyroidism, or normal functions of the thyroid gland. However, almost 15 % of the congenital hypothyroidism cases represent a disorder such as a goiter. In addition, hypothyroidism is a condition that is mostly sporadic; only ten percent of the cases are found to be inherited in newborns. Moreover, another very common cause of hypothyroidism is radiation therapy taken for cancer treatment located around the head or neck.

What Are the Causes of Congenital Goiter in Newborns and Infants?

• Abnormal Thyroid Hormone: The main reasons behind congenital goiter are abnormal thyroid hormone production, maternal antibodies, and goitrogens passed through the placenta to the fetus. Abnormal thyroid hormone production in infants is also known as dyshormonogenesis. When the genetic mutation causes the overproduction of the thyroid-stimulating hormone, a disorder such as a goiter occurs. Moreover, hypothyroidism is also another cause of goiter in young ones. The mutated genes are commonly inherited either from both parents or from either of them. Defects of either one of the processes of dyshormonogenesis can result in this disorder. These defects include no iodine concentration and defective organification of iodine, and thyroglobulin synthesis. Additionally, in some rare cases, abnormal iodine transportation can cause the genetic mutation of the protein, which in turn, causes the disorder like goiter.

• Transplacental Passage: In the cases of transplacental passage, the mother with the autoimmune thyroid disorder produces the antibodies that may pass to the fetus during the 3rd trimester. Depending on the disorder of the mother, the antibodies either cause hypothyroidism or hyperthyroidism in the fetus. Although, the condition is resolved by itself within 3 to 6 months. Finally, the transplacental of antithyroid drugs taken by the mother can also cause a disorder related to the thyroid gland.

What Are the Signs and Symptoms of Congenital Goiter in Newborns and Infants?

There are many symptoms related to the severity of this disorder, such as:

• Firm, symmetric, and non-tender thyroid gland.

• Nodular or diffuse growth on the head or neck.

• Breathing difficulties.

• Difficulties in swallowing.

• Tightness around the neck.

• Dizziness.

• Hypothyroidism: Hypothyroidism is a condition in which the thyroid gland does not produce enough thyroid hormone.

• Hyperthyroidism: Hyperthyroidism is a condition when the thyroid gland produces excessive thyroid hormone.

How to Diagnose Congenital Goiter in Newborns and Infants?

There are three types of diagnostic methods that can be used for diagnosing the goiter, such as:

• Physical Examination: Usually, the infant with congenital goiter shows physical symptoms such as an enlarged neck or nodular growth on the neck.

• Fetal Ultrasound: The ultrasound of the fetus reveals the size and development of the thyroid gland in the fetus. Also, the color doppler reveals the peripheral vascularity of the thyroid gland.

• Postnatal Ultrasound: Ultrasonography can also reveal the abnormality related to the thyroid gland and symptoms such as narrowing of the trachea due to the disorder.

• Laboratory Test: The thyroxine laboratory test can reveal the thyroxine level in the blood. Additionally, the laboratory test can also reveal elevated TSH levels and low T4 and T3 levels in the blood.

How to Manage Congenital Goiter in Newborns and Infants?

The management of the congenital goiter depends upon the severity and size of the swelling. The treatment options for the disorder include:

• T4 replacement therapy until the TSH level of blood is normal.

• Iodine supplements.

• In infants, with very large goiter, surgical therapy is the only option, as the swelling can cause complications related to normal breathing and food consumption.

• If the disorder is diagnosed in the postnatal phase, the intrauterine injection of thyroxine can also prevent this disorder in the fetus.

Conclusion:

Goiter is a rare but fatal disorder in children if left untreated. The asymmetrically enlarged thyroid gland can cause pressure on the trachea. This can further cause breathing and swallowing difficulties. Moreover, its effect on thyroid hormone production can also cause many critical complications related to health. It is essential to seek medical help at the very first sign of it.