Niamh McGrath1, Colin Patrick Hawkes2, Philip Mayne3, Nuala Patricia Murphy4. 1. Department of Paediatric Endocrinology, Children's University Hospital, Dublin, Ireland; Department of Paediatrics, School of Medicine, University College Dublin, Dublin, Ireland. Electronic address: niamhmcgrath@physicians.ie. 2. Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA; Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia, Philadelphia, PA. 3. National Newborn Screening Laboratory, Children's University Hospital, Temple St, Dublin, Ireland; Department of Paediatrics and Biochemistry, Royal College of Surgeons in Ireland, Dublin, Ireland. 4. Department of Paediatric Endocrinology, Children's University Hospital, Dublin, Ireland; Department of Paediatrics, School of Medicine, University College Dublin, Dublin, Ireland.
Abstract
OBJECTIVES: To evaluate the timing of a delayed rise in thyroid-stimulating hormone (TSH) levels in preterm infants with congenital hypothyroidism, and to determine whether cases of congenital hypothyroidism would be missed by using current consensus guidelines of repeat screening at approximately 2 weeks of age or 2 weeks after the first screening. STUDY DESIGN: The study was performed over a 13-year period (January 2004-December 2016). Whole-blood TSH samples were collected between 72 and 120 hours after birth. Repeat samples were collected weekly in preterm infants until the infant was term-corrected (37 weeks' gestation). Patients were followed up to determine whether congenital hypothyroidism was permanent or transient. RESULTS: Twenty-seven (50.9%) preterm infants born at <33 weeks of gestation who were diagnosed with congenital hypothyroidism had delayed TSH elevation and would not have been detected on first newborn screen. Twelve of these infants (40.7%) with delayed TSH elevation had decompensated hypothyroidism at diagnosis (free thyroxine [FT4] <10 pmol/L), and 4 had severe congenital hypothyroidism (FT4 <5.5 pmol/L) at diagnosis. If screening had been repeated only at 2 weeks of life, 13 infants (48%) with delayed TSH elevation would not have been identified. Of the 27 infants with delayed TSH elevation, 6 (22%) have permanent congenital hypothyroidism, and another 12 will be reevaluated at age 3 years. CONCLUSION: Repeat screening for congenital hypothyroidism in preterm infants is necessary to avoid missing cases of congenital hypothyroidism with delayed TSH elevation. Repeat screening once at 2 weeks of life will miss infants with delayed TSH elevation and decompensated permanent congenital hypothyroidism.
OBJECTIVES: To evaluate the timing of a delayed rise in thyroid-stimulating hormone (TSH) levels in preterm infants with congenital hypothyroidism, and to determine whether cases of congenital hypothyroidism would be missed by using current consensus guidelines of repeat screening at approximately 2 weeks of age or 2 weeks after the first screening. STUDY DESIGN: The study was performed over a 13-year period (January 2004-December 2016). Whole-blood TSH samples were collected between 72 and 120 hours after birth. Repeat samples were collected weekly in preterm infants until the infant was term-corrected (37 weeks' gestation). Patients were followed up to determine whether congenital hypothyroidism was permanent or transient. RESULTS: Twenty-seven (50.9%) preterm infants born at <33 weeks of gestation who were diagnosed with congenital hypothyroidism had delayed TSH elevation and would not have been detected on first newborn screen. Twelve of these infants (40.7%) with delayed TSH elevation had decompensated hypothyroidism at diagnosis (free thyroxine [FT4] <10 pmol/L), and 4 had severe congenital hypothyroidism (FT4 <5.5 pmol/L) at diagnosis. If screening had been repeated only at 2 weeks of life, 13 infants (48%) with delayed TSH elevation would not have been identified. Of the 27 infants with delayed TSH elevation, 6 (22%) have permanent congenital hypothyroidism, and another 12 will be reevaluated at age 3 years. CONCLUSION: Repeat screening for congenital hypothyroidism in preterm infants is necessary to avoid missing cases of congenital hypothyroidism with delayed TSH elevation. Repeat screening once at 2 weeks of life will miss infants with delayed TSH elevation and decompensated permanent congenital hypothyroidism.
Authors: Susan R Rose; Christopher E Blunden; Olumide O Jarrett; Kyle Kaplan; Rheta Caravantes; Henry T Akinbi Journal: J Pediatr Date: 2021-11-06 Impact factor: 4.406