Congenital Hypothyroidism is an endocrine disorder that can result from abnormal development of the thyroid, ectopic thyroid, or the inability of the thyroid gland to produce thyroid hormones. Newborns are typically asymptomatic. Some infants may exhibit clinical features such as prolonged jaundice, sleepiness, and macroglossia. If an infant is not screened and/or left untreated, symptoms begin to appear later in infancy and can include developmental delay, mental retardation, and poor growth.
Incidence: ~1/3000; affects all ethnic groups
Diagnosis: TSH values are only determined on babies with low T4 levels.
- If TSH is elevated and the T4 is low, serum free T4 and TSH should be collected and an urgent endocrinology referral should be obtained.
- If T4 is low but TSH is normal, a repeat NBS may suffice.
Treatment: Affected children require life-long thyroid hormone replacement and monitoring by both primary care and speciality providers. If treated promptly, children with congenital hypothyroidism can be asymptomatic and are expected to develop normally. Affected children should be monitored for proper height and weight gain and
False Positives: Common, especially in premature infants
Screening result can also be impacted by:
- Specimen collection less than 24 hours
- Maternal thyroid disease