Neonatal jaundice

Question 1

What is jaundice?

Answer 1

Clinical sign - Yellow colouration of skin and sclerae due to accumulation of bilirubin

Question 2

Normal factors in the neonate that make them more susceptible to jaundice

Answer 2

• Neonates: high haematocrit / RBC volume; shorter life span of RBC (70 -90 days)
• High bilirubin production
• Slow bilirubin clearance
• Immature hepatic glucuronyl transferase
• High beta glucoronidase (increased bilirubin re-absorption)
• Absent colonic bacteria

Question 3

Why neonates more susceptible to developing kernicterus?

Answer 3

BBB permeable to bilirubin for first 10-14 days of life

Question 4

Features of acute bilirubin encephalopathy

Answer 4

Lethargy, poor feeding, high pitched cry

Opisthotonus, seizures

Question 5

Features of chronic bilirubin encephalopathy

Answer 5

1. Kernicterus - histological accumulation of pigment in basal ganglia
2. BIND (bilirubin induced neurological dysfunction) - subtle intellectual impairment

Question 6

Clinical features of Kernicterus

Answer 6

Athetoid cerebral palsy
Hearing loss
Paralysis of upward gaze

Question 7

Criteria for pathological jaundice

Answer 7

• Any increase in conjugated bilirubin
• Early jaundice: before 24 hours of life
• Extremely high
• Prolonged

Question 8

Criteria suggesting physiological jaundice

Answer 8

• Elevated unconjugated bilirubin
• TSB generally peaks at about 100umol/L on day 3-4 and then declines to adult levels by day 10 (Asian infants peak at higher values)
• Exaggerated physiologic (up to 290umol/L)

Question 9

How is a diagnosis of physiological jaundice made?

Answer 9

Never appears in first 24 hours of life
Diagnosis of exclusion in active, well fed and are not ill.
TSB usually not >200umol/l (275 in breastfed)

Question 10

What is breastmilk jaundice?

Answer 10

Prolonged unconjugated physiological jaundice in a breast fed newborn
Good growth/ weight
?beta-glucuronidase increases enterohepatic circulation?

Question 11

What does beta-glucuronidase do?

Answer 11

Deconjugates glucuronic acid causing more bilirubin to be re-absorbed in the small intestine.

Question 12

Causes of an unconjugated pathological jaundice in the neonate

Answer 12

• Breast feeding jaundice
• Haemolysis
• Internal haemorrhage
• Polycythaemia
• Infant of diabetic mother
• Hypothyroidism
• Rare (Crigler-Najjar, Gilbert syndrome)

Question 13

Causes of a conjugated pathological jaundice in the neonate

Answer 13

• Congenital infections (CMV, syphilis, herpes, rubella)
• Hepatitis (TPN, viral)
• UTI
• Sepsis
• Rare: biliary atresia, cystic fibrosis, inborn errors of metabolism

Question 14

What is breastfeeding jaundice?

Answer 14

Poor breastfeeding - dehydration and weight loss.

Delayed GIT bilirubin clearance = more re-absorption

Question 15

Treatment of breastfeeding jaundice

Answer 15

Rehydration and more frequent feeding

Question 16

Causes of heamolysis in the neonate

Answer 16

Common
- Blood group incompatibility: haemolytic disease of the newborn (ABO, Rhesus, minor antigens)
- Infections / sepsis
Rare:
- Haemoglobinopathy (thalassaemia)
- RBC enzyme deficiency (glucose 6 phosphatase deficiency, pyruvate kinase deficiency)
- RBC membrane defects (spherocytosis, ovalocytosis)

Question 17

Causes of heamorrhage in the neonate

Answer 17

Common
- Bruising (traumatic delivery / resuscitation)
- Pre term / NVD
- Vaginal breech
- Cephalhaematoma, subaponeurotic haemorrhage
Rare
- Internal haemorrhage

Question 18

Most common cause of heamolytic disease of the newborn

Answer 18

ABO incompatibility

Question 19

ABO incomatibility pathophysiology

Answer 19

Maternal blood group O has IgG against A and B antigens. If child has A or B then they develop mild haemolysis. Once born placenta can no longer remove bilirubin. Therefore, accumulates.

Question 20

How do we diagnose ABO incompatibility?

Answer 20

All children born to group O mothers have TSB measured at 8 hours. If TSB > 80umol/l then phototherapy started and grouping and Coombs test is performed.

Question 21

What must the resus status of the mother and father be to get Rh disease of the newborn?

Answer 21

Mother = negative
Father = positive

Question 22

What are the major threats to the Rh diseased infants life?

Answer 22

Profound anaemia
Respiratory distress, cardiac failure
Bilirubin encephalopathy

Question 23

Features of severe Rh disease

Answer 23

Massive extra medullary haematopoiesis
Hydrops fetalis
IUD

Question 24

Why is jaundice not always seen at birth in Rh disease?

Answer 24

Placenta can remove excess biliruin

Question 25

How is Rh disease prevented?

Answer 25

IM anti-D immunoglobulin given to Resus negative woman within 72 hours following:
Delivery
Miscarriage
Amniocentesis
APH
ECV

Question 26

Clinical features of Rh disease

Answer 26

Pale large placenta
Anaemia
Jaundice (rapid onset)
HSM
Oedema
Blueberry muffin rash

Question 27

Rx for Rh disease

Answer 27

Resuscitate (Respiratory, metabolic disturbances)
Phototherapy (Start immediately, TSB every 2-4 hours)
Exchange transfusion (If cord TSB >120/ HB <30%)
Straight blood transfusion
IV immunoglobulin

Question 28

How does phototherapy work?

Answer 28

Bilirubin converted to metabolically inert, water soluble Lumiruin by blue light

Question 29

Side effects of phototherapy

Answer 29

• Hyper / hypothermia
• Skin rashes
• Diarrhoea
• Maternal anxiety / bonding

Question 30

What are the indications for exchange transfusion?

Answer 30

Cord TSB > 120
Cord Hb < 10
PCV < 30 %
Hydrops fetalis
Phototherapy failure
Signs of bilirubin encephalopathy

Question 31

What TSB level correlates to recognition of clinical jaundice?

Answer 31

> 70 umol/l

Question 32

Causes of prolonged jaundice

Answer 32

Breastmilk jaundice
Hypothyroidism
Galactosaemia
Hepatitis