Neonatal jaundice

Question 1

What can cause physiological neonatal jaundice?

Answer 1

Physiological release of Hb from haemolysis of RBCs because of high Hb conc at birth
Shorter half life of RBCs in neonates (70d)
Hepatic bilirubin metabolism less effective in first few days of life

Question 2

Why is neonatal jaundice an important sign to elicit?

Answer 2

Underlying disease
-Haemolytic anaemia, infection, inborn error of metabolism, liver disease
Kernicterus

Question 3

What is kernicterus?

Answer 3

Encephalopathy from deposition of unconjugated bilirubin in the brain, especially the basal ganglia and brainstem nuclei
Occurs when levels of unconjugated bili exceeds albumin-binding capacity of bili in the blood (bili is fat soluable, so crosses BBB)
Effects vary from transient disturbance to severe damage/death

Question 4

What are the acute manifestations of kernicterus?

Answer 4

Lethargy
Poor feeding
Severe causes include
-Irritability
-Increased muscle tone (opisthotonos, arched back presentation)
-Seizures
-Coma

Question 5

What are the long term complications of kernicterus?

Answer 5

Choreoathetoid CP (damage to basal ganglia)
Learning difficulties
Sensorineural hearing loss

Question 6

Why has the incidence of kernicterus dropped?

Answer 6

Common complication of HDN

Anti-D now given

Question 7

Which infants are at higher risk of developing kernicterus?

Answer 7

Preterm (35-37w)
Dark skinned (harder to detect)

Question 8

What are the causes of jaundice <24hrs?

Answer 8

Haemolytic disorders
-Rh incompatibility
-ABO incompatibility
-G6PD deficiency
-Spherocytosis, pyruvate kinase deficiency
Congenital infection

Question 9

What are the causes of jaundice 24hrs - 2w?

Answer 9

Physiological jaundice
Breast milk jaundice
Infection (e.g. UTI)
Haemolysis (e.g. G6PDD, ABO incompatibility)
Bruising
Polycythaemia
Crigler-Najjar syndrome

Question 10

What are the causes of jaundice >2w?

Answer 10

Unconjugated
-Physiological or breast milk jaundice 
-Infection, esp UTI
-Hypothyroidism
-Haemoloytic anaemia e.g. G6PDD
-High GI obstruction e.g. pyloric stenosis
Conjugated
-Bile duct obstruction
-Neonatal hepatitis

Question 11

How would rhesus haemolytic disease present?

Answer 11

Anaemic, hydrops, hepatosplenomegaly (rare due to antenatal monitoring)
Haemolysis may also develop to groups other than D, but this is rare

Question 12

Why does ABO incompatibility occur?

Answer 12

Some O group women have IgG anti-A-haemolysin which crosses placenta (normally ABO abs are IgM, cannot cross)
Jaundice usually less severe than Rh disease

Question 13

How is ABO incompatibility diagnosed?

Answer 13

Absent hepatosplenomegaly (vs Rh)
Hb normal/slightly raised
Positive direct Coombs test
Jaundice peaks 12-72hrs

Question 14

Which groups are at risk of G6PDD?

Answer 14

Mediterranean, Middle East, Africa
M>F
Certain drugs can precipitate haemolysis

Question 15

How is spherocytosis diagnosed?

Answer 15

Blood film
Often FHx
Less common than G6PDD

Question 16

How would congenital infection present with jaundice?

Answer 16

Conjugated bilirubin
Growth restriction
Hepatosplenomegaly
TTP

Question 17

How is physiological jaundice diagnosed?

Answer 17

Diagnosis of exclusion

Question 18

What causes breast milk jaundice?

Answer 18

Unconjugated hyperbilirubinaemia

Multifactorial, may involve increased enterohepatic circulation of bilirubin

Question 19

How can dehydration cause jaundice?

Answer 19

Jaundice exacerbated if milk intake is poor e.g. delay in establishment of breastfeeding (and infant loss >10% loss from birthweight)
Supplemental feeding may be required to reverse dehydration (IV only in extreme cases)

Question 20

How can acquired infection cause jaundice?

Answer 20

Unconjugated bilirubinaemia from
-poor fluid intake
-reduced hepatic function
-haemolysis
-increased enterohepatic circulation
UTI often presents this way

Question 21

How can jaundice severity be assessed?

Answer 21

Transcutaneous bilirubin meter/blood sample

All babies should be checked at 72hrs (if suspected, transcutaneous measurement should be performed)

Question 22

Which group are at increased risk of jaundice?

Answer 22

Preterm infants

Question 23

What pathological factors can precipitate jaundice?

Answer 23

Hypoxia, hypothermia, serious illness at increased risk of severe jaundice
Drugs that displace bilirubin from albumin e.g. sulphonamides and diazepam, should be avoided

Question 24

What management options are available to treat jaundice?

Answer 24

Poor milk intake and hydration correction
Phototherapy (conversion of bilirubin to water-soluable variety, disruptive to newborn, eye protection worn, SE = temperature instability (infant exposed), macular rash, bronze discolouration of skin (in conjugated)
Exchange transfusion (dangerously high levels, blood removed/returned in small aliquots, typically twice body volume exchanged

Question 25

What is persistent/prolonged jaundice?

Answer 25

Jaundice >2w, frequently caused by biliary atresia (needs to be recognised as a delay in surgical treatment adversely effects outcome)

Question 26

What are the causes of prolonged unconjugated hyperbilirubinaemia?

Answer 26

Breast milk jaundice (most common)
Infection, esp UTI
Congenital hypothyroidism (before other symptoms arise)

Question 27

What suggests conjugated hyperbilirubinaemia?

Answer 27

Dark urine and pale urine
Hepatomegaly and poor weight gain

Main causes include neonatal hepatitis syndrome and biliary atresia