Hypothyroidism in infants and children occurs when too little thyroid hormone is produced by the thyroid gland, leading to low levels of thyroid in the bloodstream. The "underactive" thyroid gland does not make enough thyroid hormone, interfering with growth, physical and mental development, and other body processes.
Infants and small children affected by hypothyroidism may have significant problems with growth and development if the condition is not diagnosed and treated promptly.
In older children and young adults, hypothyroidism can cause diverse symptoms. Lack of thyroid hormone can lead to slowed heart rate, chronic tiredness, inability to tolerate cold, mental fatigue and difficulty in learning, constipation, weight gain, and other problems.
Hypothyroidism can develop at any point in the lifespan. Infants can be born with hypothyroidism, and hypothyroidism can develop in children and adults of any age.
For a more detailed explanation of the thyroid gland, thyroid hormones (T3 and T4) and how affect they the body, and regulation of thyroid hormone production, see What is Hypothyroidism?
Nice To Know:
Q: We adopted a baby from another country and brought him home when he was about four months old. Our pediatrician sent us to an endocrinologist, and he says our little boy has hypothyroidism. He also used the terms congenital hypothyroidism and cretinism. What do those terms mean?
A: Congenital hypothyroidism is hypothyroidism that is present at birth. You may see it abbreviated as CH.
Cretinism is a term for abnormal growth and mental retardation due to untreated congenital hypothyroidism. Neither term is associated with any specific cause of hypothyroidism. The doctor will determine what is the cause of the hypothyroidism. You will begin to feel better as you learn more about the particulars of your son's condition and as he begins to respond to thyroid hormone treatment.
Facts about hypothyroidism in children
In North America, hypothyroidism present at birth is found in about 1 in every 4,000 newborns.
In about 10% of newborns with hypothyroidism, it is a temporary condition that will resolve within days or months.
About 95% of cases of childhood hypothyroidism are caused by a problem within the thyroid gland or by lack of a thyroid gland.
Less than 5% of cases are caused by a problem in the brain or pituitary gland.
In the developing world, most cases of congenital hypothyroidism are due to iodine deficiency in the mother and the baby.