Effects of exchange transfusion and phototherapy on neonatal thyroid functions

ABSTRACT

Hyperbilirubinemia is one of the most common problems encountered in term newborns. Phototherapy or exchange transfusion may be indicated for treatment at certain bilirubin levels. Aim of the work Is to study the effects of exchange transfusion and phototherapy on thyroid functions in full term neonates with indirect hyperbilirubinemia by assessing thyroid functions before and after exchange transfusion and during phototherapy. The present study was carried on 60 full term neonates who were grouped as follows Group I Included 20 neonates with hyperbilirubinemia reaching the level that indicated exchange transfusion. Group II included 20 neonates with hyperbilirubinemia at the level of treatment by phototherapy. Group Ill included 20 healthy neonates as a control group. All studied groups were subjected to full medical history, clinical examination and laboratory investigations including Free T3, Free T4, TSH before, immediately after and 4 days after exchange transfusion in group I, Free T3, FreeT4, TSH before and 2 days after the beginning of phototherapy in group II, Free T3, Free T4, TSH in group Ill, Free T3, T4, and TSH levels were assessed in donor blood bags prepared for exchange transfusion. In addition liver function tests, complete blood count, Coombs' test, C reactive protein, blood group of baby and mother were assessed for neonates in group I and II. We found that the levels of thyroid functions [FT3, FT4, TSH] were statistically significantly higher in neonates before exchange transfusion than immediately after exchange while there was no statistical significant difference in levels of thyroid functions before exchange transfusion and 4 days post exchange transfusion. Furthermore, the study revealed no significant differences between thyroid function tests before and during phototherapy. Moreover, there were no significant correlations between thyroid function tests and either bilirubin or hemoglobin levels of group I before exchange transfusion and group II before phototherapy. We found that exchange transfusion causes a decrease in thyroid functions immediately after exchange than before exchange and they return to normal levels four days post exchange. On the other hand, phototherapy does not affect thyroid function tests