Med. J. Cairo Univ., Vol. 79, No. 2, September: 17-21, 2011 www.medicaljournalofcairouniversity.com

Monitoring of Screening Program for Neonatal Congenital Hypothyroidism in Taif Governorate (KSA) ADNAN A. ALSULAIMANI, M.D.*; MATAR ALMALKI, (C)**; HUMAID ALSWAT, (C)*** and AHMED OSMAN, Ph.D.* The Medical College, Taif University*, King Faisal Specialist Hospital** and King Abdul-Aziz Specialist Hospital***, Taif, Saudi Arabia

Abstract

few data are available regarding the care that children receive after they are diagnosed through newborn screening program. Appropriate delivery of health care services is necessary to assure the benefit of early diagnosis [1] . We chose to focus on congenital hypothyroidism (CH) because of its relatively high prevalence compared to other conditions included in newborn screening program and because treatment is among the most straightforward should be started as early as possible.

Background: Congenital hypothyroidism is inadequate thyroid hormone production in newborn infants. This can occur because of an anatomic defect in the gland, an inborn error of thyroid metabolism, or iodine deficiency. Thyroid hormone treatment in children with congenital hypothyroidism can prevent intellectual disability. Guidelines recommend that children with congenital hypothyroidism through newborn screening program remain on treatment till at least 3 years of age, after which a trial off therapy can determine which children have transient hypothyroidism. Objectives: The purpose of this study was to describe the prevalence of congenital hypothyroidism in Taif (KSA) and effect of thyroid hormone treatment in early childhood.

Newborn screening for CH followed by the early initiation of thyroid hormone treatment to normalize thyroxin (T4) concentrations has been shown to prevent intellectual disability (i.e., mental retardation) [1-3] .

Methods: Retrospective analysis of thyroid function of newborns during the period from 1990-2009 was performed. Children were classified as having congenital hypothyroidism based on cord blood screening programme using initial cord blood thyroxine (T4), with supplemental thyrotropin (TSH), and triiodothyronine resin uptake (T3U) measurements.

The critical challenge in understanding the epidemiology of CH is that some newborns will have transient CH, a temporary depression of thyroid hormone concentrations that can last from several days to several months [4] . If confirmatory testing during the first month indicates CH, guidelines call for children to remain on treatment to at least 3 years of age, after which a trial of withdrawal off treatment can determine which children have transient hypothyroidism [5] .

Results: There were a total of 317295 children tested for congenital hypothyroidism. The overall birth prevalence of congenital hypothyroidism was about 1 per 3000. More than one-third of children treated for congenital hypothyroidism discontinued treatment within 36 months, which is inconsistent with current guidelines. Conclusions: The current findings emphasize the critical need for follow-up systems to monitor the outcome of newborn screening. It is not known how many of these children required continued treatment or experienced adverse effects following treatment discontinuation.

Since the development of the first pilot screening program for the detection of congenital hypothyroidism in Quebec in 1972, newborn screening programs have been introduced throughout the industrialized nations and are under development in many other parts of the world. It has been estimated that as of 1999, some 150 million infants had been screened for congenital hypothyroidism worldwide with 42,000 cases detected [6] . The purpose of this study was to explore the birth prevalence of presumed CH and associated risk

Key Words: Screening – Congenital – Hypothyroidism – Clinical examination – Lab. Investigation – Taif governorate.

Introduction ALTHOUGH there has been dramatic expansion in the conditions identified by newborn screening, Correspondence to: Dr. Adnan Amin Al Sulaimani, Medical College, Taif University, KSA, Email: [email protected]

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Monitoring of Screening Program for Neonatal Congenital Hypothyroidism

factors (e.g., sex and family history). Mentoring the newborn screening program through treatment till at least 3 years of age, after which a trial off therapy can determine which children have transient hypothyroidism. Patients and Methods This mass screening program included record review of newborn infants for 9 years from October 1990 till November 2009. Data were collected from 4 hospitals in Taif, Saudi Arabia. These hospitals included Al-Hada Hospital (belonging to Ministry of Defense), King Abdul-Aziz Specialist Hospital (belonging to Ministry of Health), and King Faisal Specialist Hospital (belonging to Ministry of Health). Birth prevalence of presumed congenital hypothyroidism: A checklist was prepared for data collection including information regarding sex and nationality of the neonate and family history of hypothyroidism. Clinical signs of hypothyroidism were assessed by a trained physician. Cord and venous blood samples were collected from each newborn infant and analyzed for TSH and FT4 according to the following procedure: Cord blood was obtained after delivery and ligation of the umbilical cord by withdrawing with a syringe 3 to 5ml venous blood from the placental side. This was stored and taken at 4ºC to a central laboratory. After being separated by centrifugation, sera were stored at –20ºC until analysis. All assays were performed in duplicate. Using serum samples, T4 was measured in all infants by a double antibody radioimmunoassay (RI A) technique [7,8] . Suspected cases were followed-up as quickly as possible with additional specimen for estimation of TSH, and T3, by RIA (Chopra et al., 1972). Special circumstances such as severe illness and extreme pre-maturity may require the physician's judgment on timing of the collection. Rate of thyroid hormone: At birth, the baby was resuscitated and examined by physicians for weight, sex and time to first cry. TSH was estimated within 24 hrs by enzyme immunoassay (Microwell TSH EIA) using kit provided by Syntron Bioresearch, Inc. All babies wherein the cord TSH was found to be over 20mIU/L were visited at home at 7-10 days of age and fresh samples for T3, T4, TSH, fT3 and fT4 were taken. Specimens with the lowest 10% of T4 values were repeated on a second disc and the TSH

value was checked. If the T4 is low on the screen but the TSH is normal, or if the T4 is normal but the TSH is slightly elevated, instructions for further testing were given. Our screening program is designed to keep the numbers of abnormal screens and repeat tests to a minimum. Blood samples were collected in a sterile container drawn from a 15-20cm length of the umbilical cord incised while severing it at the time of birth of the baby. Thus a mixed cord blood sample including both from the umbilical artery and vein was obtained. Babies who were born preterm (