Screening for congenital hypothyroidism in cognitively delayed children.

During the period January 1994 to December 1997, a total of 560 cognitively delayed children were prospectively screened for congenital hypothyroidism in the paediatric neurology clinic at Jordan University Hospital. Seventeen (3%) children were diagnosed to have congenital hypothyroidism. Mean age at diagnosis was 15 months (range 1.8-72 months). Main presenting symptoms (other than cognitive delay) were seizures, lethargy, poor feeding, constipation and prolonged neonatal jaundice. Thirteen (76.5%) of the 17 extrathyroid-associated anomalies involved the central nervous system (CNS). This finding reflects the study population chosen for the present study. All 17 patients had some degree of cognitive improvement ranging from slight improvement to achieving normal milestones after taking L-thyroxine. Congenital hypothyroidism is common in cognitively delayed children. The presence of major abnormality of the CNS should not be regarded as the only possible cause of cognitive delay and thyroid function should be assessed in such children.