What is Congenital Hypothyroidism?
Hypothyroidism refers to an underactive thyroid gland. Congenital Hypothyroidism (CH) occurs when a newborn infant is born without the ability to make normal amounts of thyroid hormone. In India, congenital hypothyroidism occurs in about 1 in 1500-2000 children, is most often permanent and treatment is lifelong. Thyroid hormone is important for your baby’s brain development as well as growth, therefore, untreated congenital hypothyroidism can lead to mental retardation and growth failure.
However, because there is excellent treatment available, with early diagnosis and treatment, your baby is likely to lead a normal, healthy life.
What causes Congenital Hypothyroidism?
Congenital hypothyroidism (CH) most often occurs when the thyroid gland does not develop properly, either because it is missing, is too small, or ends up in the wrong part of the neck. Sometimes the gland is formed properly but does not produce hormone in the right way. Also, sometimes the thyroid is missing the signal from the pituitary (master) gland, which tells it to produce thyroid hormone.
In a small number of cases, medications taken during pregnancy, mainly medications for treating an overactive thyroid, can lead to congenital hypothyroidism, which is temporary in most cases. CH is usually not inherited through families. This means if one child is affected, it is unlikely that other children you may have in the future will suffer from the same condition.
How is Congenital Hypothyroidism diagnosed?
Most private hospitals in India now carry out Newborn Screening for Congenital Hypothyroidism. Screening tests are done on either umbilical cord blood or baby’s capillary or venous blood sample after 48-72 hours of life. If the levels of TSH on this sample are high, the test is repeated on venous sample after 7th day of life.
The doctor may order additional blood tests like Free T4 estimation along with the confirmatory TSH sample. A persistently high TSH value suggests a diagnosis of Congenital Hypothyroidism. Once a diagnosis of CH is made, a Nuclear Scan and an Ultrasound of the thyroid are done to delineate the etiology or cause of CH.
How is Congenital Hypothyroidism treated?
Congenital hypothyroidism is treated by giving thyroid hormone medication in a tablet form called levothyroxine. Many children will require treatment for life. Levothyroxine should be crushed and given once daily, mixed with a small amount of water or breast milk using a dropper or a syringe. Giving your baby his/her thyroid hormone EVERY DAY and having regular checkups with a pediatric endocrinologist will help ensure that your baby will have normal growth and brain development.
The doctor will do periodic thyroid function tests so that the dose of medication can be properly adjusted as your child grows. To begin with, these tests would be as frequently as every 2 weeks and as the dose stabilises, the tests would be done every 2-3 monthly.
It is important to follow instructions on “How to give Thyroxine to your child” given by the doctor. The thyroid hormone in the tablet is identical to what is made in the body, and you are just replacing what is missing. In general, side effects occur only if the dose is too high, which the pediatric endocrinologist can avoid by checking blood levels on a periodic basis.