The signs and symptoms of congenital hypothyroidism are seldom apparent at birth. However, delay in treatment of a congenitally hypothyroid infant can cause irreversible brain damage. Neonatal thyroid screening has led to a marked reduction in cretinism (mental retardation and short stature due to hypothyroidism) and untreated hypothyroidism in newborns.
Acquired Childhood Hypothyroidism
Although the development of hypothyroidism in a child before puberty is uncommon, it does occur, especially if there is a family history of thyroid disease. A child’s doctor needs to know if either the mother or father has a hereditary autoimmune disease, such as Hashimoto’s thyroiditis or Graves’ disease. The doctor will then pay particular attention to the child’s thyroid examination. The first signs that a child has hypothyroidism may be thyroid enlargement and a decline in growth rate. Most short children, however, do not have hypothyroidism. Tests for hypothyroidism are frequently performed on children who are overweight, but hypothyroidism does not cause obesity. Diagnosing and treating hypothyroid children before puberty is somewhat more complicated than diagnosing and treating hypothyroid teens and adults. Children’s growth and development must be carefully monitored. In childhood, the normal range for TSH and free T4 varies with age. Levothyroxine dosage must be adjusted more frequently in growing children than in teenagers or mature adults. For all these reasons, pediatric endocrinologists are usually consulted in the management of hypothyroid infants or children. Once hypothyroid children have gone through puberty and growth has ceased, treatment is essentially the same as that of adults.
Children with Hyperthyroidism
Although hyperthyroidism is uncommon before puberty, it does occur, especially if there is a family history of thyroid disease. The two most common causes of childhood hyperthyroidism are neonatal hyperthyroidism and Graves’ disease. Approximately one out of 100 babies born to mothers with Graves’ disease develops transient neonatal hyperthyroidism. This hyperthyroidism is the result of thyroid-stimulating antibodies (TSAb or TSI) crossing the placenta and stimulating a newborn’s thyroid gland.
Neonatal hyperthyroidism is temporary and lasts until the baby metabolizes, or uses up, its mother’s TSAb or TSI. The signs and symptoms of hyperthyroidism in children are similar to those seen in adults with hyperthyroidism. However, the first sign that children are hyperthyroid may be a decline in their grades.
The treatment options for hyperthyroid children are also the same as those for adults. Treating hyperthyroid children with antithyroid drugs before puberty is more complicated than treating hyperthyroid teens and adults.