Congenital Hypothyroidism : Result of Neonatal Screening in Maharat Nakhon Si Thammarat Hospital - โรคพร่องไทรอยด์ฮอร์โมนแต่กำเนิด: ผลจากโครงการคัดกรองสุขภาพทารกแรกเกิดในโรงพยาบาลมหาราชนครศรีธรรมราช

Abstract

               Congenital hypothyroidism (CH) is one of the preventable mental retardation disorders. Neonatal screening and early thyroid hormone therapy can normalized cognitive development. A prospective study of neonates in Maharat Nakhon Si Thammarat was designed with an objective to study the incidence, etiology and clinical outcomes of the patients diagnosed as primary congenital hypothyroidism and hyperthyrotropinemia from October 1998 to September 2004. During then, thyroid stimulating hormone (TSH) screening was performed in infants aged 48 hours -7 days. Infants with elevated TSH level of greater than 25 mU/L were recalled for confirmation test. L-thyroxine was administered in infants with CH and persistent hyperthyrotropinemia. At the age of 3 years, thyroxine was discontinued for 1 month to reconfirm the diagnosis by thyroid function test and thyroid scan. Neonatal screening was performed in 33,500 neonates. The recall rate was 0.32 percent and the response rate was 95.41 percent. Neonates with abnormal thyroid function test were divided into two groups; 11 (47.83%) of CH and 12 (52.17%) of hyperthyrotropinemia. The incidence of CH was 1:3,045. All of them were asymptomatic. Thyroxine was given till 3 years of age, then discontinued for re-evaluation of the diagnosis. Thirteen (65.00%) of CH group were permanent hypothyroidism and 7 (35.00%) were transient hypothyroidism whereas 6 (37.50%) of hyperthyrotropinemia group were permanent compensated hypothyroidism and 10 (62.50%) were transient hyperthyrotropinemia. Thyroid scan was carried out in 8 patients of the permanent hypothyroidism which revealed dysgenesis in 5 cases (62.50%): 2 cases with ectopic, 2 cases with agenesis and 1 case with hypogenesis. Thyroid scan was carried out in only 2 cases of  the hyperthyrotropinemia and revealed normal thyroid gland. The incidence of CH in Maharat Nakhon Si Thammarat was 1:3,045. Permanent hypothyroidism were found in CH group more than those in hyperthyrotropinemia group. The common cause of permanent hypothyroidism was dysgenesis.

Key words: neonatal screening, congenital hypothyroidism, thyroid stimulating hormone