Healthy thyroid function is critical for infants and children, whose developing brains and bodies rely on adequate levels of thyroid hormone. Untreated, hypothyroidism can lead to intellectual disability and growth failure.
There are two types of hypothyroidism in infants and children: Congenital hypothyroidism, which is present at birth, and acquired hypothyroidism, which develops after birth, usually during late childhood or adolescence.
Congenital hypothyroidism
Congenital hypothyroidism affects 1 in 1,500-3,000 newborns in the U.S. each year. The condition most often occurs for no known reason, but 10-20% of the time it is inherited.
The disorder can result from insufficient maternal iodine consumption during pregnancy, but this is rare in the U.S., where dietary iodine is generally adequate. Rarely, medications taken during pregnancy–mainly those for treating overactive thyroid—can lead to congenital hypothyroidism, though the condition is usually transient and resolves with no effects.
Congenital hypothyroidism is one of the most common and preventable causes of intellectual disability. Because most newborns show no signs of it, the condition is usually detected during routine newborn screening, which is mandatory.
In the first few months of life, symptoms include poor appetite and choking while nursing, failure to gain weight and length, constipation, jaundice, trouble breathing, a hoarse cry, and sluggishness. The baby’s belly may be enlarged. His or her skin may feel cold and look mottled, and the genitals, hands, and feet may be swollen.
Later signs include dry, scaly skin, poor growth of hair and nails, and a delay in the appearance of teeth. The child’s growth may be stunted. His or her fingers and toes may be shorter than those of a healthy child. The child’s head may look puffy and large, and the tongue may look swollen.
Some of the long-term and possibly permanent complications of untreated hypothyroidism include:
- Cretinism – Children born with this thyroid condition can develop severe mental disabilities if the disease is not caught immediately and treated. The first year of life is the most important in the case of permanent congenital hypothyroidism. Infants lose between 3 and 5 points in IQ levels every month when the condition is undiagnosed. Treatment of congenital thyroid problems may not totally reverse the effects or stop the deterioration, and adults born with the disease often have a milder form of memory problems and the ability to process information. Slow thyroid problems developed after the age of 2 is not known to cause retardation in children.
- Peripheral neuropathy – Long-term uncontrolled hypothyroidism can cause damage to your peripheral nerves — the nerves that carry information from your brain and spinal cord to the rest of your body, for example your arms and legs. Signs and symptoms of peripheral neuropathy may include pain, numbness and tingling in the area affected by the nerve damage. It may also cause muscle weakness or loss of muscle control.
References:
https://www.webmd.com/women/tc/hypothyroidism-in-infants-children-and-teens-topic-overview
https://thyroidnation.com/common-complications-hypothyroidism/
https://www.endocrineweb.com/conditions/hypothyroidism/hypothyroidism-children
