What do Doctors call this Condition – Congenital hypothyroidism, infantile cretinism
What is this Condition?
Hypothyroidism in children is a deficiency of thyroid hormone secretion during fetal development or early infancy. Untreated hypothyroidism is characterized in infants by respiratory difficulties, persistent jaundice, and hoarse crying; in older children, by stunted growth (dwarfism), bone and muscle dystrophy, and mental deficiency.
Early diagnosis and treatment offer the best prognosis; infants treated before age 3 months usually grow and develop normally. However, hypothyroid children who remain untreated beyond age 3 months and children with acquired hypothyroidism who remain unÂtreated beyond age 2 years suffer irreversible mental retardation; their skeletal abnormalities are reversible with treatment. Hypothyroidism occurs three times more often in girls than in boys.
What Causes it?
In infants, hypothyroidism usually results from defective embryonic development that causes congenital absence or underdevelopment of the thyroid gland. The next most common cause can be traced to an inherited enzymatic defect in the synthesis of the thyroid hormone thyroxine. Less frequently, antithyroid drugs taken during pregnancy produce hypothyroidism in infants. In children older than age 2, hypothyroidism usually results from chronic autoimmune thyroiditis.
What are its Symptoms?
At birth, the weight and length of an infant with hypothyroidism appear normal, but characteristic signs of hypothyroidism develop by age 3 to 6 months. Breast-fed infants don’t show most symptoms until they’re weaned because breast milk contains small amounts of thyroid hormone.
Symptoms in Infants
Typically, an infant with hypothyroidism sleeps excessively, cries rarely (except for occasional hoarse crying), and is generally inactive.
Because of this, the parents may describe the child as a “good baby-no trouble at all.” However, such behavior actually results from a decreased metabolism and progressive mental impairment.
The infant with hypothyroidism also has abnormal deep-tendon reflexes; hypotonic abdominal muscles; a protruding abdomen; slow, awkward movements; feeding difficulties; constipation; and jaundice.
A large, protruding tongue obstructs respiration, making breathing loud and noisy and forcing the child to breathe through an open mouth. The child may have shortness of breath on exertion, anemia, abnormal facial features, and a dull expression, resulting from mental retardation. The skin is cold and mottled because of poor circulation, and the hair is dry, brittle, and dull. Teeth erupt late and tend to decay early; body temperature is below normal; and pulse rate is slow.
Symptoms in Children
In the child who gets hypothyroidism after age 2 years, appropriate treatment will likely prevent mental retardation. However, growth retardation becomes apparent in short stature, obesity, and a head that appears abnormally large because the arms and legs are stunted. An older child may show delayed or accelerated sexual development.
How is it Diagnosed?
Lab tests help determine levels of thyroid hormones. A high serum level of thyroid-stimulating hormone, associated with low levels of thyroxine and triiodothyronine, points to hypothyroidism. Since early diagnosis and treatment can minimize the effects of hypothyroidism, many states require measurement of thyroid hormone levels at birth.
Electrocardiography shows slow heart rate and electrocardiographic changes in untreated infants. Thyroid scan and radioactive iodine uptake tests show decreased uptake levels and confirm the absence of thyroid tissue in hypothyroid children. Hip, knee, and thigh X-rays reveal delayed skeletal development that is markedly inappropriate for the child’s age.
How is it Treated?
Early detection is mandatory to prevent irreversible mental retardation and permit normal physical development.
Treatment in infants under age 1 year consists of replacement therapy with oral Levoxine, starting with moderate doses. Dosage gradually increases to levels sufficient for lifelong maintenance. (However, a rapid increase in dosage may precipitate thyrotoxicity.)
Doses are proportionately higher in children than in adults because children metabolize thyroid hormone more quickly. Older children also receive Levoxine.
What can the Parents of a Child with Hypothyroidism do?
• Be aware that your child will require lifelong treatment with thyroid supplements. Stay alert for signs of overdose: rapid pulse, irritability, insomnia, fever, sweating, and weight loss. To prevent further mental impairment, be sure to comply with your child’s treatment program .
• Focus on your child’s strengths, not weaknesses. Provide stimulating activities to help the child reach maximum potential.