Jaundice Flashcards
What are risk factors for hyperbilirubinaemia?
- GA <38 wks
- sibling with neonatal jaundice who required phototherapy
- mother’s intention to breastfeed exclusively
- visible jaundice in the first 24 hrs following birth
Why does physiological jaundice occur in babies?
Physiological jaundice occurs due to the:
o Higher concentration of red blood cells in newborns
o Shorter life span of newborn red blood cells
o Slower metabolism, circulation and excretion of bilirubin in newborns
What is breast milk jaundice?
• Develops 5 to 7 days after birth and peaks at 14 days7
• At one month of age, approximately 10% of breastfed babies remain
jaundiced1
• A suggested cause is an increased concentration of β-glucuronidase in
breast milk and the associated increase in deconjugation and reabsorption
of bilirubin7
• Is benign
Why is unconjugated bilirubin bad?
Unbound unconjugated bilirubin can penetrate the blood-brain barrier. It is potentially toxic and may
result in short and/or long term neurological dysfunction. There is a poor correlation between circulating bilirubin levels and severity of encephalopathy.
What is kernicterus?
A pathology term, referring to the yellow staining of the basal nuclei of the
brain.
• The term is frequently used to refer to the clinical syndrome and sequelae, including acute and [more commonly the] chronic brain effects, of bilirubin
encephalopathy
Causes of jaundice <24 hours of age
Almost always pathological • Usually due to haemolysis: o Rhesus disease o ABO incompatibility o Red cell enzyme defects (e.g. G6PD deficiency)
• Sepsis (e.g. acute/intrauterine infection)
• Rarer causes may include:
o Other blood group incompatibilities (Kell, Duffy, anti-E)
o Red cell membrane defects (hereditary spherocytosis)
Causes of jaundice from 24 hours - 10 days of age
- Most commonly benign physiological jaundice
- Dehydration
- Sepsis
- Haemolysis
- Polycythemia
- Breakdown of extravasated blood (e.g. bruising)
- Increased entero-hepatic circulation which may be due to gut obstruction
- Metabolic disease including galactosaemia
Causes of jaundice >10 days of age
- Sepsis
- Hypothyroidism
- Hypopituitarism
- Hypoadrenalism
- Haemolytic anaemia
- Hereditary Spherocytosis
- Pyloric stenosis or gastrointestinal obstruction
- Breast milk jaundice
Investigations for jaundiced babies <24 hours old
• Routine:
o TSB (total serum bilirubin) – for baseline level to assess response to treatment
o Full blood count. Consider ± blood film
o Blood group (maternal and baby)1
o Coomb’s test
(DAT may have a weak false positive for mothers who received Anti D during pregnancy)
• Consider: o G6PD deficiency o Microbiological cultures (MC&S) of: Blood Urine Cerebrospinal fluid
Investigations for jaundiced babies 24 hours - 10 days old
• Routine1:
o TSB – for baseline level to assess response to treatment
o Full blood count. Consider ± blood film
o Blood group (maternal and baby)1
o Coomb’s test
(DAT may have a weak false positive for mothers who received Anti D during pregnancy)
o Newborn Screening Test (NBST) if not already taken
• Consider: o G6PD deficiency (at risk newborns include Mediterranean, Middle Eastern, African or Southeast Asian origin) o MC&S: Blood Urine Cerebrospinal o TORCH screen
Investigations for jaundiced babies >10 days old
**Requires investigation due to the risk of serious disease
• Medical review including:
o Examination/enquiry regarding stool colour
Pale stools and dark urine require urgent discussion with a
neonatologist/paediatrician/gastro-enterologist
o Review of previous pathology results
• Routine:
o Total and conjugated bilirubin
If conjugated bilirubin greater than 25 micromol/L refer to Table 10
o FBC + blood film
o Reticulocyte count
o Blood group
o Coomb’s test
(DAT may have a weak false positive for mothers who received Anti D during pregnancy)
o Thyroid function test (TFT) (including TSH and T4)
o Review NBST results*
• If the baby is unwell:
o Discuss with a paediatrician/neonatologist
o Consider further investigations
Septic screen
• If above test results are normal, the baby is well and breastfeeding, it is likely to be breast milk jaundice
Differentials for conjugated hyperbilirubinaemia
• Congenital obstruction and malformations of the biliary system (e.g. biliary
atresia, choledochal cyst, bile duct stenosis)
• Idiopathic neonatal hepatitis
• Infections (Hepatitis B, TORCH, sepsis, intrauterine)
• Metabolic disorders (galactosaemia, hereditary fructose intolerance, Alpha-
1 antitrypsin deficiency, tyrosinaemia, glycogen storage disease type IV,
hypothyroidism)
• Prolonged parenteral nutrition
Investigations for conjugated hyperbilirubinaemia
Conjugated hyperbilirubinaemia requires urgent discussion with a neonatologist/paediatrician/gastro-enterologist • Consider initiating investigations by requesting: o Total serum bilirubin and conjugated bilirubin levels o LFT (including: AST, ALT, GGT, ALP and albumin) o Coagulation screen o Blood gas (with blood glucose) o Liver ultrasound o Ferritin o TFTs (including TSH and T4) o Alpha-1-antitrypsin phenotype o Urine: Cytomegalovirus (CMV) PCR Culture and sensitivity Reducing substances • Additional investigations to consider include: o Urine: Organic acids Amino acids o Serum amino acids o Plasma: Ammonia Pyruvate Lactate
What happens in ABO incompatability?
ABO incompatibility describes an antibody reaction that occurs when mother and baby have different blood groups, typically maternal blood group O, and
baby blood group A or B. Some mothers have naturally occurring anti-A and anti-B antibodies present in the circulation, which can pass across the placenta
and bind to antigenic sites on fetal red cell[s]. Some mothers are sensitised by feto-maternal transfusion of ABO incompatible blood.
How do you manage jaundice in a baby <24 hours old?
A medical emergency:
o Measure and record the serum bilirubin within 2 hours of identifying obvious or suspected jaundice
***Commence phototherapy whilst awaiting serum bilirubin results
o Urgent neonatology/paediatric/medical review required:
Within 6 hours of identifying obvious or suspected jaundice
