Congenital Hypothyroidism: Symptoms, Causes and Treatment

Congenital hypothyroidism (CHT) is the medical term used to signify the deficiency of the thyroid hormone in newborn babies due to a malfunctioning thyroid gland. The condition is usually triggered by various factors like defects in the thyroid gland, deficiency of iodine or inborn defects in the metabolism of the thyroid hormone. Early detection is required for the proper treatment of this disease. If it goes unrecognized, and is not treated immediately, it can impair the normal rate of growth. It can even lead to permanent mental retardation.

Causes

Congenital hypothyroidism is of two types, permanent and transient. Permanent congenital hypothyroidism is usually caused by a defect in the development of the thyroid gland, which is known as dysgenesis. It is one of the most common causes, accounting for almost two-thirds of the total cases of the disease. On the other hand, almost 10% of the total cases of congenital hypothyroidism are caused by a defect in the formation as well as secretion of the thyroid hormone, thyroxine, which is largely an inherited defect. Secretion of the thyroid hormone is also controlled by the hypothalamus and pituitary gland, and so any problem in these parts of the body may also cause congenital hypothyroidism.

The transient congenital hypothyroidism often results from a deficiency of iodine, probably due to the insufficient intake of iodine by mother. In case, the mother is afflicted by the autoimmune thyroid disease (a disease, where the body's own immune system attacks the thyroid gland), the antibodies, known as TSH (thyroid stimulating hormone) receptor blocking antibodies may pass over to the fetus through the placenta. These antibodies can impair the functions of the thyroid gland for a few days in the newborn baby. Besides, high doses of iodine, especially iodine-based medications taken either by the mother or the baby and an error in the transportation of thyroid hormones may also cause congenital hypothyroidism.

Symptoms

Congenital hypothyroidism may not show any symptom, or the symptoms shown by the disease may be so mild that they may not be easily recognized. So, most of the times, they may go unnoticed. Such symptoms include excessive sleeping, a hoarse cry, slow movement, feeding problems, irregular bowel movement, recurring constipation, low temperature of the body, dry skin, etc. However, in severe cases, the absence of the thyroid gland in the body can produce symptoms like an enlarged fontanel (a soft spot on the forehead), umbilical hernia and a large tongue.

Diagnosis and Treatment

For early detection of the disease, the newborn babies are screened, within a few days after their birth, to check the level of thyroid stimulating hormone (TSH) and thyroxine (T4). If a high level of thyroid stimulating hormone or low thyroxine is detected, further tests are carried out to find out the actual cause of the problem.

Treatment for congenital hypothyroidism is quite simple. The disease is treated with a daily dose of thyroxine, usually available as tablets, which are administered with a small amount of water or milk. After a few weeks, the level of TSH and thyroxine is checked again to evaluate the efficacy of the treatment.

Infants with congenital hypothyroidism usually have a normal rate of growth and development if the disease is diagnosed and treated at the early stage. However, some studies have disclosed minor problems with memory and attention in those children, who either received a delayed treatment or lower starting doses of the thyroxine hormone. Therefore, the key to proper treatment of congenital hypothyroidism is the early detection of this disease. Besides, the intake of the required amount of iodine, especially during pregnancy, is also important to lower the frequency of occurrence of this disease.