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1、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(entero
2、hepatic circulation).,Introduction,60%of infants become clinically jaundiced in 1st 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 firs
3、t 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 a
4、lbumin in equilibrium with its unbound or free fractionthe 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 bilir
5、ubin,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
6、 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 fun
7、ction 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 pr
8、emature 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,preterm15mg/dl),Factors likely to make“physiological jaundice”worse,prematurity bruising cephalohemat
9、oma polycythaemia delayed passage of meconium breast feeding certain ethnic groups,esp Chinese,Characteristics of Pathological Jaundice,Jaundice appears within 24 hrs of life Severe jaundice:SBR1215mg/dl,or 5mg/dl/day Sustained jaundice(term2w,preterm4w)Recurrence of jaundice Increased serum conjuga
10、ted bilirubin(1.52mg/dl),Pathological Jaundice,Infectious diseasesNeonatal hepatitis(Torch infection)Neonatal septicemia Non-infectious diseasesHemolytic diseasesBiliary atresiaBreast milk jaundiceGenetic metabolic diseases:G6PD,a1-antitrypsin,CFDrugs induced:Vitamin K3,K4,Breast Milk Jaundice,Occur
11、s infrequently(1%),peaks in 23wk,may persist at moderately high levels for 3-4 weeks before declining slowly It is a diagnosis of exclusionIn an otherwise well infant,it is considered a benign condition.If breast feeding stopped,the serum bilirubin usually fallsThe potential harms of stopping breast
12、 feeding would outweigh any risks of a mild or moderate hyperbilirubinaemiaAetiology 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
13、first week of life in infants who are breast feddue to both caloric deprivation(mostly)and some fluid deprivation(a small part)during the first few days of lifeThe more frequently breast feeding occurs during the first few days,the lower are subsequent bili levelscan be prevented by teaching effecti
14、ve breast-feeding practices and support policies,Clinical Investigation:Kramers Rule,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 dis
15、ease 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 1st pregnancy In severe cases fetal anaemia develops,causing congestive cardiac failure(hydrops fet
16、alis)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 d
17、ay 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 encepha
18、lopathy(Kernicterus)Early(27d):more in preterm,includes hypertonia,lethargy,feeding difficulty,seizures,1/3 death,bilirubin staining of the basal gangiaLate:Survivors may go on to develop sensorineural hearing loss and cerebral palsy,often with ataxia and choreoathetosis;disorders in eye movement;en
19、amel hypoplasia,Diagnosis,Family history:still birth,abortion,jaundice Parents ABO/Rh typing,antibody Ultrasound for hydrops fetalis Postnatal:jaundice,anemia,neurological symptom Blood type and antibody,Direct Coombs,Antibody release,&Free antibody Test,Management,Prenatal:Rh(-),monitoring antibody
20、,bilirubin,etcTerminate pregnancy when lungs are maturedPlasma transfusion to remove antibodyIntrauterine blood transfusionMaternal use of phenobarbitone to induce enzyme,Phototherapy,Isomerisation of unconjugated bilirubin Wave length:427475nm(blue),510530nm(green)Blue light,green light/day lightPr
21、otection of eyes/gonadInvisible water lossSide effects:skin rash,fever,diarrheaBeware of conjugated hyperbilirubinemia(bronze baby),Phototherapy,Exchange Transfusion,Prenatal diagnosed,Hb12 mmol/L/hr(0.75mg/dl)SBR 342 mmol/L(20mg/dl)Preterm/Rh history/Hypoxia/Acidosis/SepsisFor Rh:Rh same as mother,
22、ABO same as infantFor ABO:AB/plasma and O/RBS;or type OVolume:150180ml/kg via umbilical vein catheter,Other Intervention,Albumin(1g/kg),plasma(25ml)Correct acidosisPhenobarbitone(5mg/kg)to induce enzymesIntravenous immunoglubulin(1g/kg)Prevent hypoxia/hypothermia/hypoglycemiaAnti RhD IgG(300mg,im)for Rh(-)mother after delivered a Rh(+)baby(within 72h)Good perinatal care,
