Neonatal Hypothyroidism

Neonatal hypothyroidism is decreased thyroid hormone production in a newborn. In very rare cases, no thyroid hormone is produced. The condition is also called congenital hypothyroidism. Congenital means present from birth.

Causes
Hypothyroidism in the newborn may be caused by:
♦ A missing or poorly developed thyroid gland
♦ A pituitary gland that does not stimulate the thyroid gland
♦ Thyroid hormones that are poorly formed or do not work
♦ Medicines the mother took during pregnancy
♦ Lack of iodine in the mother's diet during pregnancy
♦ Antibodies made by the mother's body that block the baby's thyroid function

A thyroid gland that is not fully developed is the most common defect. Girls are affected twice as often as boys.

Symptoms
Most affected infants have few or no symptoms. This is because their thyroid hormone level is only slightly low. Infants with severe hypothyroidism often have a unique appearance, including:
♦ Dull look
♦ Puffy face
♦ Thick tongue that sticks out

This appearance usually develops as the disease gets worse.

The child may also have:
♦ Choking episodes
♦ Constipation
♦ Dry, brittle hair
♦ Jaundice
♦ Lack of muscle tone (floppy infant)
♦ Low hairline
♦ Poor feeding
♦ Short height
♦ Sleepiness
♦ Sluggishness

Exams and Tests

A physical exam may show:
♦ Decreased muscle tone
♦ Slow growth
♦ Hoarse-sounding cry or voice
♦ Short arms and legs
♦ Very large soft spots on the skull (fontanelles)
♦ Wide hands with short fingers
♦ Widely separated skull bones

Blood tests are done to check thyroid function. Other tests may include:
♦ Thyroid ultrasound scan
♦ X-ray of the long bones


Treatment

Early diagnosis is very important. Most of the effects of hypothyroidism are easy to reverse. For this reason, most US states require that all newborns be screened for hypothyroidism.

Thyroxine is usually given to treat hypothyroidism. Once the child starts taking this medicine, blood tests are regularly done to make sure thyroid hormone levels are in a normal range.

Outlook (Prognosis)

Getting diagnosed early usually leads to a good outcome. Newborns diagnosed and treated in the first month or so usually have normal intelligence.

Untreated mild hypothyroidism can lead to severe intellectual disability and growth problems. The nervous system goes through important development during the first few months after birth. Lack of thyroid hormones can cause damage that cannot be reversed.


When to Contact a Medical Professional

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


Prevention

If a pregnant woman takes radioactive iodine for thyroid cancer, the thyroid gland may be destroyed in the developing fetus. Infants whose mothers have taken such medicines should be observed carefully after birth for signs of hypothyroidism. Also, pregnant women should not avoid iodine-supplemented salt.

Most states require a routine screening test to check all newborns for hypothyroidism. If your state does not have this requirement, ask your provider if your newborn should be screened.


Alternative Names

Cretinism; Congenital hypothyroidism


References

LeFranchi SH, Huang SA. Hypothyroidism. In: Kliegman RM, Stanton BF, St. Geme, Schor NF, eds.Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 565.

Van Vliet G, Deladoëy J. Disorder of the thyroid in the newborn and infant. In: Sperling MA, ed.Pediatric Endocrinology. 4th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 7.

Article Collected from: https://medlineplus.gov


Symptoms in infants
In the first few months of life, symptoms include poor appetite and choking while nursing, failure to gain weight and length,constipation, jaundice, trouble breathing, a hoarse cry, and sluggishness. The baby's belly may be enlarged. His or her skin may feel cold and look mottled, and the genitals, hands, and feet may be swollen.

Later signs include dry, scaly skin, poor growth of hair and nails, and a delay in the appearance of teeth. The child's growth may be stunted. His or her fingers and toes may be shorter than those of a healthy child. The child's head may look puffy and large, and thetongue may look swollen.

Infants are treated with synthetic thyroid hormone replacement. Aninfant treated for hypothyroidism within the first month of life grows and develops normally. Treatment must be continued for life. Ifhypothyroidism occurs after age 3, intellectual disability usually does not occur. But untreated childhood hypothyroidism usually delays a child's physical growth and sexual development.

Symptoms in children and teens

Early signs may include lethargy and goiter. Other symptoms such as behavior changes, changes in school performance, and persistent belly pain may also be present. These signs are more suspicious in a child whose parents or siblings also have thyroid problems.
There usually is some delay in growth and development. But it is not as severe as delays that may result from hypothyroidism during infancy. Physical growth and sexual development are mainly affected. The onset of puberty is delayed, and children with hypothyroidism usually look much younger than they are. Children may also gain weight and yet have a slowed growth rate.

Children and teens also need lifelong treatment with synthetic thyroidhormone replacement. With adequate treatment, a child will catch up in height and weight to healthy children of the same age.

Atricle from: http://www.webmd.com/