Neonatal jaundice Flashcards
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What can cause physiological neonatal jaundice?
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
Why is neonatal jaundice an important sign to elicit?
Underlying disease
-Haemolytic anaemia, infection, inborn error of metabolism, liver disease
Kernicterus
What is kernicterus?
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
What are the acute manifestations of kernicterus?
Lethargy Poor feeding Severe causes include -Irritability -Increased muscle tone (opisthotonos, arched back presentation) -Seizures -Coma
What are the long term complications of kernicterus?
Choreoathetoid CP (damage to basal ganglia)
Learning difficulties
Sensorineural hearing loss
Why has the incidence of kernicterus dropped?
Common complication of HDN
Anti-D now given
Which infants are at higher risk of developing kernicterus?
Preterm (35-37w) Dark skinned (harder to detect)
What are the causes of jaundice <24hrs?
Haemolytic disorders -Rh incompatibility -ABO incompatibility -G6PD deficiency -Spherocytosis, pyruvate kinase deficiency Congenital infection
What are the causes of jaundice 24hrs - 2w?
Physiological jaundice Breast milk jaundice Infection (e.g. UTI) Haemolysis (e.g. G6PDD, ABO incompatibility) Bruising Polycythaemia Crigler-Najjar syndrome
What are the causes of jaundice >2w?
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
How would rhesus haemolytic disease present?
Anaemic, hydrops, hepatosplenomegaly (rare due to antenatal monitoring)
Haemolysis may also develop to groups other than D, but this is rare
Why does ABO incompatibility occur?
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
How is ABO incompatibility diagnosed?
Absent hepatosplenomegaly (vs Rh)
Hb normal/slightly raised
Positive direct Coombs test
Jaundice peaks 12-72hrs
Which groups are at risk of G6PDD?
Mediterranean, Middle East, Africa
M>F
Certain drugs can precipitate haemolysis
How is spherocytosis diagnosed?
Blood film
Often FHx
Less common than G6PDD
How would congenital infection present with jaundice?
Conjugated bilirubin
Growth restriction
Hepatosplenomegaly
TTP
How is physiological jaundice diagnosed?
Diagnosis of exclusion
What causes breast milk jaundice?
Unconjugated hyperbilirubinaemia
Multifactorial, may involve increased enterohepatic circulation of bilirubin
How can dehydration cause jaundice?
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)
How can acquired infection cause jaundice?
Unconjugated bilirubinaemia from -poor fluid intake -reduced hepatic function -haemolysis -increased enterohepatic circulation UTI often presents this way
How can jaundice severity be assessed?
Transcutaneous bilirubin meter/blood sample
All babies should be checked at 72hrs (if suspected, transcutaneous measurement should be performed)
Which group are at increased risk of jaundice?
Preterm infants
What pathological factors can precipitate jaundice?
Hypoxia, hypothermia, serious illness at increased risk of severe jaundice
Drugs that displace bilirubin from albumin e.g. sulphonamides and diazepam, should be avoided
What management options are available to treat jaundice?
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
What is persistent/prolonged jaundice?
Jaundice >2w, frequently caused by biliary atresia (needs to be recognised as a delay in surgical treatment adversely effects outcome)
What are the causes of prolonged unconjugated hyperbilirubinaemia?
Breast milk jaundice (most common)
Infection, esp UTI
Congenital hypothyroidism (before other symptoms arise)
What suggests conjugated hyperbilirubinaemia?
Dark urine and pale urine
Hepatomegaly and poor weight gain
Main causes include neonatal hepatitis syndrome and biliary atresia
