MON-103 Pattern and Predictors of Thyroid Dysfunction Among Paediatric Endocrine Referrals at Tertiary Care Centre: A Longitudinal Study

Abstract

Background Post iodisation era has experienced gradual change in pattern of thyroid disorders among paediatric population with autoimmunity taking precedence over iodine deficiency disorders and subclinical hypothyroidism (SCH) now more frequently diagnosed but inappropriately managed. Aims This study was conducted to evaluate pattern of abnormal thyroid function among children referred to our tertiary care centre, to ascertain characteristics that influence treatment decisions and to follow them for various outcome measures. Design It was an observational longitudinal follow up study where all children less than 18 years, referred to our outpatient clinic for suspected thyroid disorder were recruited. Demographic data, personal and family history, clinical features were noted and laboratory tests including TT4, TT3, TSH, anti-thyroid peroxidase(antiTPO) and anti-thyroglobulin(antiTG) antibody were conducted in study subjects. Management was based on the clinical judgment of the attending endocrinologist. Patients were followed at 6 week, 3 months, 6 months and one year with clinical and laboratory work up at each visit. Results A total of 241 subjects aged 18 days to 17 years were included out of which 62.25% were females. Initial evaluation revealed SCH in 40% of refereed subjects, overt hypothyroidism (OH) in 33%, congenital hypothyroidism (CH) in 18% and overt thyrotoxicosis in 5%. Autoimmune thyroiditis constituted the major cause of hypothyroidism in the OH group with significantly higher prevalence of anti-TPO and antiTG antibody in comparison of SCH group (61% vs 31%; 45% vs 21.9%, p<0.05) respectively. All subjects in OH group were treated whereas 76% subjects in SCH group were treated and the mean dose of L thyroxine required to treat OH was significantly higher (2.31+1.1ug/kg/day vs 1.76+1.07ug/kg/day; p<0.001) in comparison of SCH group. A major independent predictor of treatment in SCH was initial TSH which was significantly higher in the treated group (11.65 + 3.80 uIU/ml vs 9.24 + 1.31 uIU/ml; p<0.001). Subjects with congenital hypothyroid presented at a mean age of 6 months (18 days to 2 years) with most common aetiology being thyroid hypoplasia and dyshormonogenesis(20% each). Graves’ disease was diagnosed in 11 out of 12 subjects with thyrotoxicosis and were treated with antithyroid drugs. Overall 85.5% of refereed subjects were treated and after one-year follow up management was found to be adequate in 81% subjects. Conclusions The evolving trend of diagnosing children having nonspecific symptoms with SCH is a matter of concern as many are subjected to the burden of unwanted prolonged treatment and frequent testing as highlighted in our study. Delayed presentation of CH in our study warrants active surveillance of children at birth for thyroid disorders to avoid long term adverse effects on mental development.