Congenital hypothyroidism

Alternative names:

cretinism

Definition:

The absence of thyroid function in the newborn resulting from one of several problems or defects that can occur during pregnancy.

Causes, incidence, and risk factors:

Hypothyroidism in the newborn may result from absence or lack of development of the thyroid gland, destruction of the thyroid gland, failure of stimulation of the thyroid by the pituitary, and/or by defective or abnormal synthesis of thyroid hormones. Absence or lack of development of the thyroid is the most common defect and occurs at a rate of 1 out of every 6,000 to 7,000 births. Girls are more often affected than boys.

Hypothyroid infants often have a distinctive appearance with a puffy-appearing face, a dull look, and a large tongue that protrudes from the mouth, which is usually kept open. They usually develop this appearance as the disease progresses. They may have dry brittle hair, low hairline and jaundice. Feeding is poor and the infant may choke frequently. Constipation is common. Affected children do not cry much, but sleep excessively and are sluggish and inactive. Muscle tone is usually decreased.

If untreated, hypothyroidism can lead to severe mental retardation and growth retardation. Development is delayed early on, often indicated by failure to meet normal milestones. The appearance of teeth may be delayed. These problems become more severe as the child ages. Growth failure in terms of body length is noted very early.