An Audit of Thyroid Function Testing Among Infants with Down Syndrome Over a Four Year Period

Introduction: Infants with Down Syndrome (DS) have an increased risk of thyroid dysfunction and congenital hypothyroidism.[i] [ii] [iii]. Most countries have adapted TSH based screening for Congenital Hypothyroidism using a heel prick test[iv],[v] Irish and International guidelines recommend screening for thyroid dysfunction in Down Syndrome with the Newborn Screening Programme and repeating serum TSH and T4 at 6 months and annually thereafter.[vi]

Objectives: 1.To determine the percentage of infants with Down Syndrome who undergo inappropriate thyroid function tests in the first three months of life. 2. To implement a pre-discharge checklist for neonates with DS.

Methodology: All neonates born with Down Syndrome between 1/1/2012 and 1/9/2016 were included. Blood results were reviewed retrospectively on the Hospitals APEX software system. If thyroid function testing was preformed before 3 months of age, charts were reviewed for an indication. The standard was based on the ‘National Guideline for the Medical Management of Children and Adolescents in Ireland with Down Syndrome’. This states that Newborn Screening is an adequate screen for thyroid dysfunction in DS and venous thyroid function testing be carried out at least once every two years from their first year. A standard of 90% was set.

Results: 100 babies with Down Syndrome were included. 40% (n=40) had serum thyroid function tests. 4% had a maternal history of thyroid dysfunction and 4% were repeated as requested by the National Newborn Screening programme. 32% had no indication. 6 of the 32 had abnormal repeat TSH but all had normal T4 levels.

Conclusion: 32% had inappropriate thyroid function tests. This means unnecessary cost to the hospital, a poor use of time and staff resources taking the blood and an unnecessary physical and emotional burden to the patient and their parents. This was below the standard set. A checklist for all children diagnosed with Down Syndrome has now been introduced and this audit will be repeat in one year time.