单击此处编辑母版标题样式,*,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,Neonatal,Jaundice,(,Hyperbilirubinemia,),Introduction,All babies develop elevated serum bilirubin(SBR)levels,to a greater or lesser degree,in the first week of life.This is due to:,increased production(accelerated RBC breakdown);,decreased removal(liver enzyme insufficiency),Increased,reabsorption,(,enterohepatic,circulation).,Introduction,60%,of infants become clinically jaundiced in 1,st,wk,Bili,levels peak at 35 days in full term infants,1/6 of formula fed infants have,bili,levels over 12,1/3 of breast fed infants have,bili,levels over 12,Over 80%of all infants with,bili,levels12.9 mg/dl in,the first four days of life are breast fed,Bilirubin Metabolism,derived from the catabolism of proteins that contain,heme,the most important source is the breakdown of,Hb,from RBC,native bilirubin is relatively insoluble in water at physiologic,pH,but it is very lipid soluble,bilirubin circulates bound to albumin in equilibrium with its unbound or free fraction,the unbound fraction that readily crosses the blood-brain barrier and results in,neurotoxicity,Bilirubin Metabolism,Bilirubin is made more water-soluble in the liver by conjugation with,glucuronic,acid to form conjugated or direct-reacting bilirubin,then cleared through the bile into the intestines and out through the feces.,Phototherapy,works by producing,photoisomers,of bilirubin that are more water soluble,and that can be cleared directly in bile or urine without conjugation in the liver.,“,enterohepatic,circulation”:,b,-,glucuronidase,in the gut hydrolysis the conjugated bilirubin into,unconjugated,bilirubin,and reabsorbed into liver,Characteristics of Neonatal Bilirubin Metabolism,Increased bilirubin production,8.8mg/kg daily,vs,3.8mg/kg in adults,Insufficiency of bilirubin transportation,acidosis,hypoalbuminemia,Immature of liver function,lower ingestion(y,z protein);lower UDPGT activity,Increased,“,enterohepatic,circulation”,lower in gut bacteria;higher,b,-,glucuronidase,activity,“Physiological”Jaundice,Seen in 60%of term infants and over 80%of,preterm,Serum values reaches maximum at 6mg/dl on 45d in,term and 1012mg/dl on 57d in premature infants,Jaundice declines gradually,reaching normal values,within 2 wks in term,and 34w(12m)in,preterm,Causes no damage in term infants,Up limit for abnormal?Undefined,(Term 12mg/dl,or term13,preterm,1215mg/dl,or 5mg/dl/day,Sustained jaundice(term2w,preterm,4w),Recurrence of jaundice,Increased serum conjugated bilirubin(1.52mg/dl),Pathological Jaundice,Infectious diseases,Neonatal hepatitis(Torch infection),Neonatal septicemia,Non-infectious diseases,Hemolytic diseases,Biliary atresia,Breast milk jaundice,Genetic metabolic diseases:G6PD,a,1-,antitrypsin,CF,Drugs induced:Vitamin K3,K4,Breast Milk Jaundice,Occurs infrequently(1%),peaks in 23wk,may persist at,moderately high levels for 3-4 weeks before declining slowly,It is a diagnosis of exclusion,In an otherwise well infant,it is considered a benign condition.,If breast feeding stopped,the serum bilirubin usually falls,The potential harms of stopping breast feeding would outweigh any risks of a mild or moderate,hyperbilirubinaemia,Aetiology,is unknown,some hormonal in the milk may acting on the infants hepatic metabolism,or enzyme(lipase)facilitating intestinal absorption of bilirubin.,Breast-feeding Jaundice,increased bilirubin levels seen during the first week of life in infants who are breast fed,due to both caloric deprivation(mostly)and some fluid deprivation(a small part)during the first few days of life,The more frequently breast feeding occurs during the first few days,the lower are subsequent,bili,levels,can be prevented by teaching effective breast-feeding practices and support policies,Clinical Investigation:Kramers Rule,Zone,1,2,3,4,5,SBR(,m,mol,/L),100,150,200,250,250,Cephalocaudal,Progression of Jaundice,Clinical Investigation,Total SBR,conjugated SBR,full blood count-may reveal,spherocytes,or septic,Group&Direct Coombs test hemolytic jaundice,high TSH&low T4-suspect thyroid disease,G6PD screen-male and appropriate ethnic group,sepsis screen if indicated,galactosaemia,Rhesus,isoimmunisation,Rh,antigen:C,D,E,c,d,e,most common type is,RhD,Rh,(-)refers to D-,Rare in un-transfused 1,st,pregnancy,In severe cases fetal,anaemia,develops,causing,congestive cardiac failure(,hydrops fetalis,),The fetus is protected with placental removal of,bilirubin,following rapidly rising SBR after birth,ABO Incompatibility,Most often seen in the setting of mother being group,O and the baby being groups A or B,Milder that Rhesus disease,rarely affects the fetus,Jaundice that becomes apparent on day 1 or 2,Diagnosis with blood groups and direct Coombs Test,Responds well to,phototherapy,Rarely requires exchange transfusion,1/5,for ABO,1/20 for,Rh,incompatibility will becoming hemolytic,Clinical Manifestation,Jaundice:within 24h in 77%of,Rh,28%in ABO,Anemia,Hepatosplenomegaly,Bilirubin,encephalopathy,(,Kernicterus,),Early(,27d):more in,pre