Jaundice

Question 1

how common is jaundice

Answer 1

very common
60% of term
80% of preterm

Question 2

at what age does most jaundice appear

Answer 2

day 2-3 of life

Question 3

what clinical sign is due to high levels of bilirubin

Answer 3

jaundice

Question 4

what produces bilirubin

Answer 4

breakdown of red blood cells

Question 5

what does haem breakdown produce

Answer 5

unconjugated bilirubin

Question 6

what is most unconjugated bilirubin bound to when circulating

Answer 6

albumin

Question 7

some bilirubin is free in plasma - why do we worry about this stuff

Answer 7

it can cross the blood brain barrier

Question 8

heme —> _______ —-> bilirubin

Answer 8

biliverdin

Question 9

which type of bilirubin is water insoluble

Answer 9

unconjugated

Question 10

which type of bilirubin is water soluble

Answer 10

conjugated

Question 11

where is unconjugated bilirubin metabolised to conjugated bilirubin

Answer 11

liver

Question 12

what is unconjugated bilirubin sometimes called

Answer 12

indirect bilirubin

Question 13

what is conjugated bilirubin sometimes called

Answer 13

direct bilirubin

Question 14

what enzyme metabolises/causes conjugation of bilirubin

Answer 14

UDPGT

Question 15

why are newborns inefficient at managing bilirubin

Answer 15

ligandin and UDPGT are low in the newborn

Question 16

what does enterohepatic circulation refer to in newborns (bilirubin)

Answer 16

a percentage of the conjugated bilirubin that passes into the gut reverts to unconjugated bilirubin and is recirculated into the bloodstream.

Question 17

give an example of a disease causing an enzyme abnormality that affects conjugation of bilirubin

Answer 17

Gilbert’s disease

Question 18

which gene is mutated in gilbert’s disease

Answer 18

UGT1A1

Question 19

what does unconjugated bilirubin crossing the BBB cause

Answer 19

encephalopathy which can lead to kernicterus

Question 20

what additional factors are required to put a baby at significant risk of encephalopathy

Answer 20

decreasing gestation
asphyxia
acidosis
hypoxia
hypothermia
meningitis
sepsis

Question 21

why do we worry about jaundice

Answer 21

because of the neurological effects it can have

Question 22

Pathological jaundice

Answer 22

physiological jaundice that’s too high
haemolysis
sepsis
metabolic disorders
liver disease

Question 23

which timing of jaundice is considered pathological until proven otherwise

Answer 23

early jaundice - 0-24hrs

Question 24

in what time frame does physiological jaundice usually appear

Answer 24

24-72hrs

Question 25

late prolonged jaundice

Answer 25

persisting over 14 days in term and 21 days in preterm

Question 26

why does physiological jaundice develop

Answer 26

- increased bilirubin production; foetal RBC lifespan is shorter, high Hct, bruising - decreased uptake and binding by liver cells (normal development of baby) - decreased conjugation (most important) - decreased excretion - increased enterohepatic circulation of bilirubin

Question 27

are babies great at conjugating bilirubin

Answer 27

nope

Question 28

what underlying cause should you watch out for in early jaundice

Answer 28

sepsis

Question 29

what is jaundice under a day old usually due to

Answer 29

a haemolytic event, with excessive production of bilirubin

Question 30

why might a baby be born with jaundice (so like immediate jaundice)

Answer 30

severe haemolysis hepatitis (unusual)

Question 31

causes of haemolysis

Answer 31

ABO incompatibility Rh immunisation Sepsis

Question 32

when would you consider hepatitis as a cause of haemolysis

Answer 32

if there is substantial elevation of conjugated bilirubin (>15% of the total)

Question 33

which tests detect antibodies on the baby's red cells

Answer 33

Direct Agglutination Test elution test

Question 34

what test would be positive in blood group incompatibility

Answer 34

Direct Agglutination Test (DAT)

Question 35

what would Direct Agglutination Test result be in haemolysis

Answer 35

negative

Question 36

bilirubin encephalopathy symptoms

Answer 36

- lethargy - poor feeding - temperature instability - hypotonia

Question 37

bilirubin encephalopathy severe and very rare symptoms

Answer 37

- arching of head, neck and back (Opisthotonos) - spasticity - seizures

Question 38

conjugated bilirubin above which percentage needs investigating?

Answer 38

>15% of the total bilirubin

Question 39

causes of persistent UNconjugated hyperbilirubinaemia

Answer 39

- breast milk jaundice - poor milk intake - haemolysis - infection (especially UTI) - hypothyroidism

Question 40

what does persistent CONJUGATED hyperbilirubinaemia signify

Answer 40

a hepatitis

Question 41

what is biliary atresia

Answer 41

a rare condition causing obstructive jaundice a section of the bile duct is either narrowed or absent

Question 42

biliary atresia symptoms

Answer 42

jaundice pale, clay coloured stools dark urine

Question 43

what operation do babies with biliary atresia need before 3 months of age

Answer 43

Kasai portoenterostomy