neonatal jaundice Flashcards
where do babies get jaundice first
face
bilirubin metabolism
unconjugated bilirubin is metabolised by the liver to conjugated bilirubin which can be excreted into the gut
why are babies inefficient at managing bilirubin
- liver metabolism relies on bilirubin uptake via ligandin and then conjugation by uridine diphosphoglucuronyltransferase (UDPGT)
- both ligandin and UDPGT are low in the new born making newborns inefficient
what is enterohepatic cirulation
in newborns a percentage reverts to unconjugated bilirubin and is recirculated into the blood stream
how can gilberts disease affect jaundice
- mutation of the UGT1A1 gene
- reduces bilirubin-UGT
- makes jaundice worse
what happens when bilirubin crosses the BBB
- causes encephalopathy which can lead to kernicterus
- small risk of cerebral palsy with high levels
risk factors for brain damage by bilirubin
- decreasing gestation
- asphyxia
- acidosis
- hypoxia
- hypothermia
- meningitis
- sepsis
causes of neonatal jaundice
physiological (normal)
pathological
- haemolysis
- sepsis
- metabolic disorders
- liver disease
at what hours is jaundice seemed pathological
0-24 hours
when is jaundice seemed physiological
24-72 hours
what causes physiological jaundice
- increased production
- decreased uptake and binding by liver cells
- decreased conjugation
- decreased excretion
- increased enterohepatic circulation of bilirubin
causes of pathological jaundice
- due to haemolysis
- hepatitis
- ABO incompatibility
- Rh immunisation
- sepsis
- red cell enzyme defects
- red cell membrane defects
investigation of early pathological jaundice
- total bilirubin concentration
- maternal blood group and antibody titres
- baby’s blood group
- full blood count
- CRP if maybe infection
- measure conjugated bilirubin if clinical concern
what does bilirubin encephalopathy present with
- lethargy
- temperature instability
- hypotonia
- arching of the head, neck and back
- spasticity
- seizures
what is jaundice at 24 hours - 10 days
jaundice that is physiological but its so so high that it is pathological
called ‘too high’ jaundice
causes of ‘too high’ jaundice
- mild dehydration
- insufficient milk supply
- breakdown of extravasted blood
- some is haemolysis
- infection
- gut obstruction causing increased extrahepatic circulation
what is prolonged jaundice
> 14 days term
or
21 days preterm
causes of persistent unconjugated hyperbilirubinaemia
- breast milk jaundice
- poor milk intake
- haemolysis
- infection (especially UTI)
- hypothyroidism (babies are screened for this)
causes of persistent conjugated hyperbilirubinaemia
NOT NORMAL
- hepatitis (caused by injection or metabolic disorders)
- biliary atresia
what is biliary atresia
- rare disorder causing obstructive jaundice which is fatal if not treated
- infants usually have pale stools and dark urine
- requires surgery
presentation of breast milk jaundice
- persistent jaundice in otherwise healthy breast fed baby
- normal conjugated portion
- normal FBC and blood group
- no sign of infection
- thriving
- reassurance and no further action
treatment of jaundice
- treat cause if there is one
- adequate feeding/hydration
- enteral feeding
- breast milk is best, may need formula
- sometimes tube feeding
- phototherapy is mainstay
- exchange transfusion
- IV immunoglobulin
signs that the jaundice is likely physiological
- onset day 2
- peak day 5
- resolve by day 10-14
- otherwise well infant
signs that the jaundice is likely pathological
- onset day 1
- peak day is variable
- prolonged after day 14
- symptoms and signs of aetiological cause
