Congenital hypothyroidism (patient information)

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 * Associate Editor(s)-In-Chief: Jinhui Wu, M.D.

Overview
Congenital hypothyroidism is a disorder that affects infants from birth and results from a partial or complete loss of thyroid function. Researches demonstrate mutations in the DUOX2, PAX8, SLC5A5, TG, TPO, TSHB, and TSHR genes may be involved in the causes of congenital hypothyroidism. Usual signs and symptoms include increased birth weight, puffy face, swollen tongue, hoarse cry, low muscle tone, constipation, fatigue and weakness. Tests of serum thyroid-stimulating hormone (TSH) and T4 can tell the diagnosis. Treatment for congenital hypothyroidism is to replace the lacking thyroid hormone. Levothyroxine is the most commonly used medication for replacement. The earlier the treatment of hormone replacement therapy starts, the better outcoms will be.

What are the symptoms of Congenital hypothyroidism?

 * Some babies with congenital hypothyroidism do not appear any signs at birth.


 * Some may have one or more of the following symptoms:
 * Weight gain
 * Puffy face
 * Swollen tongue
 * Hoarse cry
 * Low muscle tone
 * Cold intolerance
 * Persistent constipation
 * Fatigue and weakness
 * Little to no growth
 * Without therapy, the child later may show signs of neurological impairment.

What causes Congenital hypothyroidism?

 * Hypothyroidism in the newborn may be caused by:
 * A missing or abnormally developed thyroid gland
 * Pituitary gland's failure to stimulate the thyroid
 * Defective or abnormal formation of thyroid hormones


 * Incomplete development of the thyroid is the most common defect and occurs in about 1 out of every 3,000 births. Girls are affected twice as often than boys.

Who is at highest risk?
Mutations in the DUOX2, PAX8, SLC5A5, TG, TPO, TSHB, and TSHR genes result in congenital hypothyroidism.

When to seek urgent medical care?
Call your health care provider if:
 * You feel your infant shows signs or symptoms of hypothyroidism
 * You are pregnant and have been exposed to antithyroid drugs or procedures

Diagnosis

 * Laboratory tests of determination thyroid function, including serum thyroid-stimulating hormone (TSH) and T4 test.
 * TSH test: This test is the most accurate measure of thyroid function. General speaking, a TSH reading above normal means a person has hypothyroidism and a reading below normal means a person has hyperthyroidism.
 * T4 test: This test measures the actual amount of circulating thyroid hormone in the blood. In hypothyroidism, the level of T4 in the blood is lower than normal.
 * Bone age test: In babies with hypothyroidism, they show signs of bone with an immature appearance.

Treatment options
The purpose of treatment is to replace the lacking thyroid hormone as early as possible. The hormone replacement therapy is necessary for normal brain and intellectual development. The earlier the treatment begins, the better the outlook will get for most children with congenital hypothyroidism. Levothyroxine is the most commonly used medication. When your baby is taking thyroid hormone medications, regular blood tests need to be checked to ensure the hormone levels in a normal range.

Diseases with similar symptoms

 * Rickets
 * Down's syndrome
 * Congenital megacolon

Where to find medical care for Congenital hypothyroidism?
Directions to Hospitals Treating Congenital hypothyroidism

What to expect (Outlook/Prognosis)?

 * Prognosis of congenital hypothyroidism depends on whether the baby starts thyroid hormone replacement therapy early.


 * The earlier the treatment begins, the better outcome the baby will be.

Possible complications

 * Mental retardation
 * Growth retardation
 * Heart problems

Prevention
There is no prevention for congenital hypothyroidism. A screening test in newborns between 24 and 72 hours old may be used to detect congenital hypothyroidism.