India, Feb. 15 -- My 3-year-old daughter feels tired most of the time and is not growing well. The paediatrician ordered thyroid tests, and hypothyroidism has been diagnosed. Is this a serious problem? Will she need to take medication for life? Hypothyroidism is a condition in which the thyroid gland does not produce enough thyroid hormone called thyroxine. The thyroid is a small gland that plays a big role in a child's growth and development. Thyroxine is essential for normal brain development, physical growth, energy levels, and the functioning of the body. The production of thyroxine is controlled by another hormone, TSH, released from the pituitary gland in the brain. When the thyroid gland is not working properly, thyroxine levels fall, and the pituitary gland releases more TSH. As a result, in hypothyroidism, TSH levels are high while thyroxine levels are low. Hypothyroidism in children can be present from birth (congenital hypothyroidism) or develop later during childhood or adolescence (acquired hypothyroidism). Congenital hypothyroidism may happen if the thyroid gland is absent, not formed normally, located in the wrong place, or present but unable to produce enough hormone. In some cases, it may be related to the mother having thyroid disease, taking medicines that suppress thyroid function, or having iodine deficiency during pregnancy. Studies show that congenital hypothyroidism is more common in India than in Western nations. Recent research from areas where newborn screening is conducted suggests nearly one out of every 1,000 babies may be affected. (1) In many babies with congenital hypothyroidism, there may be no obvious symptoms in the first few weeks of life. Some may show signs such as prolonged jaundice after birth, poor feeding, delayed milestones like late head control, poor growth, hoarse cry, large tongue, constipation, dry skin, or anaemia. If congenital hypothyroidism is not detected and treated early, it can lead to permanent intellectual disability. Thus, newborn screening is recommended. This test is usually done between three and five days after birth by taking a small drop of blood from the baby's heel and checking the TSH level. Acquired hypothyroidism is more commonly seen in adolescents, especially girls. The most common cause is Hashimoto's thyroiditis, in which the body's immune system mistakenly attacks the thyroid gland. Other causes include iodine deficiency or damage to the thyroid due to surgery, cancer, or radiation therapy. Children may develop a swelling in the front of the neck due to enlargement of the thyroid gland, called a goitre. Other symptoms include tiredness, muscle aches, constipation, dry and coarse skin and hair, excessive sleepiness, poor concentration, and a decline in school performance. Because the body's metabolism slows down, some children may gain weight. Growth may slow down, leading to short height, and puberty may be delayed. Adolescent girls may have irregular or heavy menstrual periods. The diagnosis is confirmed through blood tests that measure TSH and thyroxine levels. But in babies, a thyroid scan may be advised to check the size, structure, and position of the gland. The treatment is simple: taking a thyroxine tablet daily. When treatment for congenital hypothyroidism is started within the first two weeks to one month of life, normal growth and brain development can be achieved. Children with acquired hypothyroidism also respond very well to treatment. Regular blood tests are needed to adjust the dose, but with proper treatment and follow-up, most children lead completely normal, healthy lives. The duration of thyroxine treatment varies from child to child. While some children may eventually stop the thyroxine, others may need to continue it for life. [1] Anne RP, Rahiman EA. Congenital hypothyroidism in India: A systematic review and meta-analysis of prevalence, screen positivity rates, and aetiology. Lancet Reg Health Southeast Asia. 2022. Dr Anupam Sibal is a leading paediatric gastroenterologist and hepatologist with over three decades of experience and five books to his credit, including the national bestseller Is Your Child Ready to Face the World?...