Hypothyroidism in Children Beyond 5 y of Age: Delayed Diagnosis of Congenital Hypothyroidism

Abstract

To determine the frequency of undiagnosed congenital hypothyroidism (CH) and its manifestations in hypothyroid children presenting beyond 5 y of age. Retrospective analysis of records of children with hypothyroidism more than 5 y of age at presentation between October 1997 and April 2010. Three hundred twenty children were diagnosed with hypothyroidism. Ninety-four (29.3%) were ≥5 y at presentation. Of these, CH was diagnosed in 34 (36.1%) and acquired hypothyroidism (AH) in 60 (63.9%). Symptoms of CH were noted at a mean age of 35.3±25.9 mo (range 12-132 mo) while the mean age at presentation was 86.6±35.3 mo (range 60-216 mo). The mean interval between onset of symptoms and diagnosis was nearly 51 mo. The mean duration of symptoms before diagnosis in children with AH was significantly shorter (8 mo, p<0.001). The main presenting complaints in children with CH and AH were growth delay (100%) and thyroid swelling (65%) respectively. Mean fT4 values in CH and AH at presentation were 0.23 and 0.34 ng/dL respectively (p=0.019). Children with CH had significantly higher TSH values (377.4 mIU/L) as compared to those with AH (151.4 mIU/L) (p=0.002) and had significantly delayed bone age (mean difference in chronological age and bone age 4.9 y in CH vs. 2.0 y in AH, p<0.01). Most common cause of CH in this group was thyroid dysgenesis (51.8%), followed by agenesis (25.9%) and dyshormonogenesis (22.2%). In absence of a universal screening program, diagnosis of CH, an important cause of preventable mental retardation is often delayed in India.