A REVIEW OF THE CONGENITAL HYPERTHYROIDISM CLINICAL FEATURE AND DIAGNOSIS GUIDELINES

Neonate thyroid investigation notified infants who have congenital hypothyroidism and require proper initiation of thyroid hormone replacement. With the adoption of lesser limit by many screening programs, more infants are being notified, although it is not clear if the milder cases benefit from long term therapy. Thyroid testing acquires in the first 1-2 days after birth often leads to increased total T4, free T4, and/or thyroid-stimulating hormone (TSH) levels. This takes place as a result of the normal surge in TSH after birth and no treatment is required. Very premature and sick neonates often have low total and free T4 levels with normal TSH levels. The reasons for this are not distinct and treatment is rarely necessary, as total and freeT4 levels typically normalize in 6 to 10 weeks. Neonate notified with normal free T4 and mildly increased TSH levels in the neonatal period need close follow-up but not all require treatment; the increased TSH will prove to be transient in approximately half the cases. Many studies have shown that in sick low birth weight infants, especially those less than 1500 g and those born before 30 weeks’ gestation, there may be a delayed elevation of TSH, possibly related to an immaturity of the hypothalamic- pituitary thyroid axis. Retesting such infants at 3 to 4 weeks of age or before discharge from the hospital in the state newborn screening laboratory is suggested. Key words: Congenital hyperthyroidism, clinical features, thyroid stimulating hormone, graves diseas