新生儿黄疸（英文）

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1、NeonatalJaundice(Hyperbilirubinemia)IntroductionAllbabiesdevelopelevatedserumbilirubin(SBR)levels,toagreaterorlesserdegree,inthefirstweekoflife.Thisisdueto:increasedproduction(acceleratedRBCbreakdown);decreasedremoval(liverenzymeinsufficiency)Increasedreabsorption(

2、enterohepaticcirculation).Introduction~60%ofinfantsbecomeclinicallyjaundicedin1stwkBililevelspeakat3~5daysinfullterminfants~1/6offormulafedinfantshavebililevelsover12~1/3ofbreastfedinfantshavebililevelsover12Over80%ofallinfantswithbililevels>12.9mg/dlinthefirstfour

3、daysoflifearebreastfedBilirubinMetabolismderivedfromthecatabolismofproteinsthatcontainhemethemostimportantsourceisthebreakdownofHbfromRBCnativebilirubinisrelativelyinsolubleinwateratphysiologicpH,butitisverylipidsolublebilirubincirculatesboundtoalbumininequilibrium

4、withitsunboundor"free"fractiontheunboundfractionthatreadilycrossestheblood-brainbarrierandresultsinneurotoxicityBilirubinMetabolismBilirubinismademorewater-solubleintheliverbyconjugationwithglucuronicacidtoform"conjugated"or"direct-reacting"bilirubin,thenclearedthr

5、oughthebileintotheintestinesandoutthroughthefeces.Phototherapyworksbyproducingphotoisomersofbilirubinthataremorewatersoluble,andthatcanbecleareddirectlyinbileorurinewithoutconjugationintheliver.“enterohepaticcirculation”:b-glucuronidaseintheguthydrolysistheconjugat

6、edbilirubinintounconjugatedbilirubin,andreabsorbedintoliverCharacteristicsofNeonatalBilirubinMetabolismIncreasedbilirubinproduction8.8mg/kgdailyvs3.8mg/kginadultsInsufficiencyofbilirubintransportationacidosis,hypoalbuminemiaImmatureofliverfunctionloweringestion(y,z

7、protein);lowerUDPGTactivityIncreased“enterohepaticcirculation”loweringutbacteria;higherb-glucuronidaseactivity“Physiological”JaundiceSeenin60%ofterminfantsandover80%ofpretermSerumvaluesreachesmaximumat6mg/dlon4~5dintermand10~12mg/dlon5~7dinprematureinfantsJaundiced

8、eclinesgradually,reachingnormalvalueswithin2wksinterm,and3~4w(1~2m)inpretermCausesnodamageinterminfantsUplimitforabnormal?Undefined(Term<12mg/dl,