3 - Paeds - Gastro - Jaundice

Question 1

why are >50% of newborns visibly jaundiced

Answer 1

• 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

Question 2

Neonatal jaundice important to deal with because???

Answer 2

• unconj bilirubin can deposit in basal ganglia - causing kernicterus
• sign of other disorder eg haemolytic anaemia, infection, metab disease, liver disease

Question 3

Kernicterus - encephalopathy due to? occurs when?

Answer 3

unconj bilirubin deposition in BG and brain stem nuclei

when unconj bilirubin level exceeds albumin binding capacity - free bilirubin can then cross BBB.

Question 4

clinical features of kernicterus - pre-severe? if severe?

Answer 4

lethargy, poor feeding

if severe - irritability, incr muscle tone -> arched back, seizures, coma

Question 5

Infants who survive kernicterus may develop which 3 things?

Answer 5

LDs
sensorineural deafness
choreoathetoid cerebral palsy

Question 6

describe the bilirubin pathway or conjugation etc

Answer 6

Hb breakdown > unconj bili bound to albumin > enters liver > conjugated > excretion in bile 
conj bili (water sol) give urine and stools darkness

Question 7

causes of unconj jaundice (5)

Answer 7

breast milk jaundice (physiological), infection (UTI), Hypothyroidism, Haemolytic anaemia (G6PD def), high GI obstruction (PS)

Question 8

Causes of conjugated jaundice (3)

Answer 8

bile obstruction (biliary atresia, choledochal cyst)
neonatal hepatitis syndrome (CF, a1 Antitrypsin def, congenital infection) 
Intrahepatic biliary hypoplasia

Question 9

What suggests conj jaundice

Answer 9

dark urine and pale stools

hepatomegaly and poor wt gain also

Question 10

Classification by age - causes
<24h
2d-2wks
>2wks

Answer 10

<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

Question 11

Haemolytic disorders causing EARLY jaundice (4)

Answer 11

rhesus disease - usually dealt with antenatally
ABO incompatibility - less severe than Rh
G6PD def - mainly ethnic males
Spherocytosis - FHx, spherocytes on blood film

Question 12

Features of congenital infection causing jaundice

Answer 12

conj bili

infants have other signs eg growth restriction, hepatosplenomegaly, thrombocytopenic purpura

Question 13

2d - 2wk jaundice - 3 causes

Answer 13

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

Question 14

Ix to do initially?

Answer 14

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

Question 15

Ix to do once seen jaundice O/E? what to consider in ethnic/preterm babies?

Answer 15

measure with transcutaneous meter or blood sample - a high TC measurement must be checked with bloods

preterm/ethnic have lower threshold

Question 16

MGMT - initially? then? when to step up? to what?

Answer 16

correct poor intake/dehydration
then phototherapy
step up if bili reached dangerous levels - to Exchange transfusion (continue phototherapy)

Question 17

What can phototherapy cause? what if bili rising?

Answer 17

can cause macular rash and bronze discolouration if conj jaundice - if rising, give continuously