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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 reabsorpt
2、ion (enterohepatic 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/d
3、l 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 circula
4、tes 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 “d
5、irect-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 circulatio
6、n”: 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, hypoalbum
7、inemia 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 4
8、5d 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, preterm15mg/dl),Factors likely to make “physiological ja
9、undice” worse,prematurity bruising cephalohematoma 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, pret
10、erm4w ) 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, a1-anti
11、trypsin, 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 stopp
12、ed, 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
13、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
14、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,Cephalocaudal Progression of Jaundice,Clinical Investigation,Total SBR conjugated SBR full blood count - may reveal spherocyt
15、es 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-t
16、ransfused 1st 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 t
17、he 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 h
18、emolytic,Clinical Manifestation,Jaundice: within 24h in 77% of Rh, 28% in ABO Anemia Hepatosplenomegaly Bilirubin encephalopathy (Kernicterus) Early (27d): more in preterm, includes hypertonia, lethargy, feeding difficulty, seizures, 1/3 death, bilirubin staining of the basal gangia Late: Survivors
19、may go on to develop sensorineural hearing loss and cerebral palsy, often with ataxia and choreoathetosis; disorders in eye movement; enamel hypoplasia,Diagnosis,Family history: still birth, abortion, jaundice Parents ABO/Rh typing, antibody Ultrasound for hydrops fetalis Postnatal: jaundice, anemia
20、, neurological symptom Blood type and antibody,Direct Coombs, Antibody release, & Free antibody Test,Management,Prenatal: Rh (-), monitoring antibody, bilirubin, etc Terminate pregnancy when lungs are matured Plasma transfusion to remove antibody Intrauterine blood transfusion Maternal use of phenob
21、arbitone to induce enzyme,Phototherapy,Isomerisation of unconjugated bilirubin Wave length: 427475nm (blue), 510530nm (green) Blue light, green light/day light Protection of eyes/gonad Invisible water loss Side effects: skin rash, fever, diarrhea Beware of conjugated hyperbilirubinemia (bronze baby)
22、,Phototherapy,Exchange Transfusion,Prenatal diagnosed, Hb12 mmol/L/hr (0.75mg/dl) SBR 342 mmol/L (20mg/dl) Preterm/Rh history/Hypoxia/Acidosis/Sepsis For Rh: Rh same as mother, ABO same as infant For ABO: AB/plasma and O/RBS; or type O Volume: 150180ml/kg via umbilical vein catheter,Other Intervention,Albumin (1g/kg), plasma (25ml) Correct acidosis Phenobarbitone (5mg/kg) to induce enzymes Intravenous immunoglubulin (1g/kg) Prevent hypoxia/hypothermia/hypoglycemia Anti RhD IgG (300mg, im) for Rh (-) mother after delivered a Rh (+) baby (within 72h) Good perinatal care,Sleep well, Baby!,