Hypothyroidism in Children

What is Hypothyroidism in Children ?

A deficiency of thyroid hormone secretion during fetal development or early infancy results in congenital hypothyroidism, formerly called cretinism. Hypothyroidism is three times more common in girls than in boys.

Early diagnosis and treatment allow the best prognosis, and infants treated before age 3 months usually grow and develop normally. However, children with deficient thyroid activity who remain untreated beyond age 3 months and children with acquired hypothyroidism who remain untreated beyond age 2 suffer irreversible mental retardation.

Causes of Hypothyroidism in Children

In infants, hypothyroidism usually results from defective embryonic development that causes congenital absence or underdevelopment of the thyroid gland. The next most common cause is an inherited enzymatic defect in the synthesis of thyroxine (T4). caused by an autosomal recessive gene. Less frequently, antithyroid drugs or a profound iodine deficiency during pregnancy produce hypothyroidism in infants. In children older than age 2, hypothyroidism usually results from chronic autoimmune thyroiditis.

Signs & Symptoms of Hypothyroidism in Children

Common symptoms of hypothyroidism include:

• In most cases, this occurs when a baby's liver can't metabolize a molecule called bilirubin, which normally forms when the body recycles old or damaged red blood cells and Yellowing of the skin and whites of the eyes.
• Frequent choking.
• A large, protruding tongue.
• depression
• muscle weakness
• poor appetite
• hair loss
• constipation
• muscle cramps

In general, children and teens who develop hypothyroidism have the same Signs and symptoms as adults do, but they may also experience:

• Delayed development of permanent teeth
• Poor mental development
• Poor growth, resulting in short stature

Diagnostic tests

Serum thyroid-stimulating hormone (TSH) level is high and associated with low T4 and triiodothyronine (T3)levels in hypothyroidism. Because early detection and treatment can minimize the effects of hypothyroidism, many states require measurement of infant thyroid hormone levels at birth.

Thyroid scan (¹³¹I uptake test) shows decreased uptake levels and confirms the absence of thyroid tissue in children.

Gonadotropin levels are increased and compatible with sexual precocity in older children. These findings may coexist with hypothyroidism.

X-rays of the hip, knee, and thigh reveal the absence of the femoral or tibial epiphyseal line and delayed skeletal development that is markedly inappropriate for the child's chronological age.

Skull X-ray, computed tomography scan, and magnetic resonance imaging may show a pituitary or hypothalamic lesion.

T4 level, if low and associated with a low TSH level, suggests hypothyroidism secondary to hypothalamic or pituitary disease, a rare condition.

Treatment

Treatment for infants under age 1 consists of replacement therapy with oral levothyroxine, beginning with moderate doses. Dosage gradually increases to levels sufficient for lifelong maintenance. (Rapid increase may precipitate thyrotoxicity.) Doses are proportionately higher in children than in adults because children metabolize thyroid hormone more quickly.

Levothyroxine is also used to treat older children.

Prevention Tips

There is no way to prevent hypothyroidism.