الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Thyroid dysfunction especially congenital hypothyroidism (CHT), are the most important endocrinal problems, which might proceed to irreversible neurological deficits in case of delayed diagnosis or treatment of neonate. In preterm and low-birth-weight (LBW) infants, thyroid function is often altered. It is well known, in fact, that frequently in preterm newborns, the function of hypothalamic–pituitary–thyroid axis is attenuated at birth for an unknown postnatal duration. A unique form of congenital hypothyroidism has been described in preterm infants. This atypical form of hypothyroidism is characterized by a delayed elevation in TSH concentration, such that preterm infants pass their first newborn screening test but are detected on repeat screening. The aim of our study was to detect delayed thyroid stimulating hormone elevation in preterm neonates with gestational age )≤ 33 weeks) and birth weight (≤ 1800 gram( at age of one month and to determine whether cases of congenital hypothyroidism would be missed by using the current screening program. Our study a prospective study that carried out at Neonatal Intensive Care Unit (NICU) in Tanta University Hospital over a period of one year. A total of 50 preterm neonates with gestational age (≤ 33 weeks) and their birth weight less than (≤1.8 kg) enrolled in our study. The enrolled patient divided according to birth weight into: group 1: Included 25 preterm neonates with low birth weight (LBW) their birth weight (1.5:1.8 kg). Summary & Conclusions 91 group 2: Included 25 preterm neonates with very low birth weight (VLBW) their birth weight less than (<1.5 kg). Inclusion criteria: • Preterm newborn (≤ 33-week gestation) admitted to NICU. Exclusion criteria: • Full term newborns. • Neonatal mortality < 48 h of life. Methods: All neonates were subjected to the following after an informed consent from their parent and approval from the Ethical Committee of Tanta University Hospital: o Full history for every involved case will be taken including prenatal, antenatal, postnatal and maternal history (diseases and medications). o All cases in the study will be clinically examined for: • General conditions such as activity, skin color any obvious congenital abnormalities or syndromatic features. • Vital signs (respiratory rate, heart rate, temperature and blood pressure). • Anthropometric measures (weight, head circumference, abdominal circumference and height), sex, delivery mode, Apgar score in the first and fifth minute, and gestational age using New Ballard score. o Routine laboratory Investigations a. Complete blood picture. b. CRP. Summary & Conclusions 92 c. Total and direct serum bilirubin. d. Serum urea and creatinine level. o Specific laboratory Investigations: 1) Neonatal Thyroid Screening (NTS) ▪ TSH level is the first screening according to Egyptian National Screening Program. All 3-to-7-day neonates were screened using dry blood spot on filter paper taken from a prick heel capillary blood sample. ▪ TSH was measured using enzyme linked immune-sorbent assay (ELISA). Samples were considered positive if the neonatal TSH (NTSH) concentration was ≥15μu/ml. 2) Thyroid Function Tests (TFTs) ▪ Thyroid Stimulating hormone (TSH) ▪ Free Thryroxine level (FT4) ▪ Free Triiodothyronine level (FT3) All newborns included in the study underwent two TFTs, including measurement of TSH, free thyroxine (FT4) and free triiodothyronine (FT3) levels. TFT was first performed 1 week after birth and was again performed in 4th week regardless of previous results. Serum TSH, FT4 and FT3 levels were measured by chemiluminescent microparticle immunoassay. o The results of the current study demonstrated that: ▪ There was no statistically significant difference within the two groups as regard gender, mode of delivery, head circumference, APGAR1 and APGAR 2, prenatal history of (DM, HTN & PROM), Complete blood picture, CRP, serum urea, creatinine, total and direct Summary & Conclusions 93 serum bilirubin, level of FT4 at birth and at one month and level of FT3 at birth and at one month. ▪ There was statistically significant difference between the two studied groups according to gestational age (p value <0.001). ▪ There was a statistically significant difference between the two studied groups according to birth weight (p value <0.001). ▪ There was statistically significant difference between the two studied groups according to birth length (p value <0.001). ▪ There was statistically significant difference between the two studied groups according to level of TSH as TSH was higher in group II (P<0.001) and there is statistically significant difference observed between serum TSH at birth and at one month in both groups. There is increase in TSH level in both groups at one month (P<0.001). ▪ There was significant –ve correlation in the two studied groups between TSH at one month with the Birth weight.