Flashcards in 3 - Paeds - Gastro - Jaundice Deck (17):
why are >50% of newborns visibly jaundiced
-marked physiological release of Hb from breakdown of RBCs (high Hb conc at birth)
-newborns RBC lifespan only 70d
-hepatic bilirubin metabolism less efficient in first few days
Neonatal jaundice important to deal with because???
-unconj bilirubin can deposit in basal ganglia - causing kernicterus
-sign of other disorder eg haemolytic anaemia, infection, metab disease, liver disease
Kernicterus - encephalopathy due to? occurs when?
unconj bilirubin deposition in BG and brain stem nuclei
when unconj bilirubin level exceeds albumin binding capacity - free bilirubin can then cross BBB.
clinical features of kernicterus - pre-severe? if severe?
lethargy, poor feeding
if severe - irritability, incr muscle tone -> arched back, seizures, coma
Infants who survive kernicterus may develop which 3 things?
choreoathetoid cerebral palsy
describe the bilirubin pathway or conjugation etc
Hb breakdown > unconj bili bound to albumin > enters liver > conjugated > excretion in bile
conj bili (water sol) give urine and stools darkness
causes of unconj jaundice (5)
breast milk jaundice (physiological), infection (UTI), Hypothyroidism, Haemolytic anaemia (G6PD def), high GI obstruction (PS)
Causes of conjugated jaundice (3)
bile obstruction (biliary atresia, choledochal cyst)
neonatal hepatitis syndrome (CF, a1 Antitrypsin def, congenital infection)
Intrahepatic biliary hypoplasia
What suggests conj jaundice
dark urine and pale stools
hepatomegaly and poor wt gain also
Classification by age - causes
<24h - usually haemolysis - important to ID before unconj bili levels get too high
2d-2wks - physiological
>2wks (persistent/prolonged neonatal jaundice) - ?biliary atresia - usually unconj due to breast milk/infection/congenital hypothyroidism
Haemolytic disorders causing EARLY jaundice (4)
rhesus disease - usually dealt with antenatally
ABO incompatibility - less severe than Rh
G6PD def - mainly ethnic males
Spherocytosis - FHx, spherocytes on blood film
Features of congenital infection causing jaundice
infants have other signs eg growth restriction, hepatosplenomegaly, thrombocytopenic purpura
2d - 2wk jaundice - 3 causes
breast milk jaundice (inc enterohepatic circ of bii)
Dehydration (poor intake/delay)
Infection (unconj from poor fluid intake, haemolysis, reduced hep function + inc enterohepatic circ)
other - crigler najjar
Ix to do initially?
inspection in bright natural light -> sclera, gums, blanched skin (starts on head > trunk/limbs)
Stool colour - pale = biliary tree/post hepatic obstruction of conj bili
Ix to do once seen jaundice O/E? what to consider in ethnic/preterm babies?
measure with transcutaneous meter or blood sample - a high TC measurement must be checked with bloods
preterm/ethnic have lower threshold
MGMT - initially? then? when to step up? to what?
correct poor intake/dehydration
step up if bili reached dangerous levels - to Exchange transfusion (continue phototherapy)