1: Neonatology - Jaundice Flashcards
What causes jaundice
Hyperbillirubinaemia
What % of neonates will experience some form of jaundice
60
What time-frame does physiological neonatal jaundice occur
> 24h.
Usually 2-14d.
What are 4 causes of physiological jaundice
- Shorter RBC lifespan
- Hepatic Immaturity
- Absence Gut Flora
- Exclusive Breast Feeding
Explain hepatic immaturity
Unable to conjugate bilirubin for excretion leading to accumulation
Why may absence of gut flora cause physiological jaundice
Unable to eliminate bile pigment
Why may breast feeding cause jaundice
Feeding difficulties can lead to dehydration, relatively increasing bilirubin.
What does jaundice in first -24h always indicate
Pathological cause
What are four possible causes of jaundice within the first 24 hours
- Rhesus haemolytic disease
- ABO haemolytic disease
- Hereditary spherocytosis
- G6PD deficiency
What test can be used for rhesus haemolytic disease
Direct Coombs Test
What test can be used to detect hereditary spherocytosis
Fragility Test
Define prolonged jaundice in term infant
> 14d
Define prolonged jaundice in pre-term infant
> 21d
What are 5 causes of prolonged jaundice
- Biliary atresia
- Hypothyroidism
- Sepsis - TORCH
- Cystic Fibrosis
- Galactosaemia
What causes unconjugated hyperbillirubinaemia in first 24h
Haemolytic disease:
- Rhesus
- ABO
- G6P
- Hereditary Spherocytosis
What causes conjugated hyperbillirubinaemia in first 24h
TORCH Infection
What causes uncognjugated hyperbillirubinaemia in 2-14d
- Physiological Jaundice
- Breast Feeding Jaundice
What causes unconjugated hyperbillirubinaemia >14d
- Breast Milk Jaundice
- Congenital Hypothyroid
- TORCH
How will conjugated hyperbillirubinaemia present
Pale stools, Dark Urine
What causes conjugated hyperbillrubinaemia >14d
- Biliary atresia
- Neonatal hepatitis
What are 5 risk factors for pathological jaundice
- Low birth weight
- Pre-mature
- Previous sibling affected
- Birth trauma
- Known Rhesus or ABO incompatibility
How will conjugated hyperbilirubinaemia present
Pale Stools
Dark Urine
What causes conjugated hyperbillirubinaemia
Biliary Atresia
Neonatal hepatitis
What does hepatomegaly and splenomegaly associated with jaundice indicate
It is not associated with physiological jaundice - therefore pathological cause
What is breast feeding jaundice
Infant breast feeds it can lead to dehydration. This can reduce clearance of bilirubin
When does breast feeding jaundice occur
Day 2-14
What is breast milk jaundice
Breast Milk contains B-glucoronidase. It reduces conjugation and increases absorption of billirubin causing persistent physiological jaundice
When does breast milk jaundice occur
> 14d
When should all babies be checked for jaundice
Newborn Infant Physical Exam - in 72h. Or 48h if risk factors.
What is first line investigation for jaundice babies
Measure Bilirubin
When should serum bilirubin measurement be used
If neonate less than 24h. Or delivered less than 35W gestation.
When should transcutaneous billrubinometer be used
If neonate more than 24h. Or, delivered more than 35W
If a transcutaneous bilirubinometer shows a bilirubin of more than 250 what should be done
Serum bilirubin
If a jaundice baby is less than 24h, how often should serum bilirubin be measured
Measure within 2h. Then monitor every 6h.
If a jaundice baby is more than 24h, how often should serum bilirubin be measured
6h.
What tests may be used to identify cause of jaundice in first 24-hours
- Coombs Test
- Blood group
If clinically indicated what other tests may be performed
FBC
Blood Film
G6PD enzyme levels
Blood culture
Which gender is G6PD more likely in
Males
If a conjugated billirubinaemia what may be performed and why
US bile duct and GB due to risk of biliary atresia
If bile duct dilated on US what may it indicated
Choledochal cyst
If bile duct is not dilated dilated on US what may be performed
TIBDA scan
What defines term
37-40W delivery
What defines prolonged jaundice in a term baby
> 14d
What defines prolonged jaundice in a pre-term baby
> 21d
What is a prolonged jaundice screen
- Pale Stools/ Dark Urine
- Bilirubin
- FBC
- Blood Group
- Urine culture
- TFTs
What does bilirubin level determine
It is plotted on a graph against time to determine if phototherapy or exchange transfusion is required
What is phototherapy and how does it work
Phototherapy uses UV light to covert bilirubin to soluble products (eg. lumirubin) that can be excreted without conjugation
What are side effects of phototherapy for jaundice
- Eye damage
- Seperation from mother
If jaundice due to ABO or Rhesus incompatibility - what is given alongside phototherapy
IVIG
What is exchange transfusion
Donor warmed blood is given to foetus by umbilical vein and removed from umbilical artery. Aim is to remove high bilirubin
If biliary atresia is suspected how is jaundice managed
Urgent surgical review
What worrying syndrome may hyperbillirubinaemia cause
Acute bilirubin encephalopathy
When does acute bilirubin encephalopathy occur
First few days of life
How will acute bilirubin encephalopathy present
- Lethargy
- Hypotonia
- Irritable
- Poor Feeding
- Shrill Cry
What is kernicterus
Progression from acute bilirubin encephalopathy
What are three RF for kernicterus
- Rapidly rising Increase in bilirubin >8.5
- Serum bilirubin >340
- Clinical features bilirubin encephalopathy
How will kernicterus present
- Vertical Gaze Palsy
- Cerebral paresis
- Hearing Impairment
- Athetosis
- Intellectual disability
- Dental enamel hypoplasia
Why would jaundice due to biliary atresia not cause kernicterus
As only unconjguated hyperbillirubinaemia can cross the BBB to cause kernicterus. Conjugated is water-soluble and therefore cannot cross BBB
What is biliary atresia
Obliteration or discontinuity of biliary tract
In which gender is biliary atresia more common
Females
How does biliary atresia present clinically
- Prolonged jaundice
- Dark urine
- Pale stools
What is a sign of biliary atresia
Hepatosplenomegaly
Explain pathophysiology of biliary atresia
Obliteration of biliary tree, leads to cholestasis increases pressure causing portal HTN
What investigations are ordered in biliary atresia
LFTs
USS
TBIDA scan
What may be seen on LFTs in biliary atresia
High conjugated bilirubin
Normal total bilirubin
Abnormal liver transaminases
What may be seen on USS in biliary atresia
Non-patent biliary tree
What may be seen on TBIDA scan in biliary atresia
Non-patent biliary tree
What is management of biliary atresia
Hepatoportenterostomy = anastamosis between liver and small intestine
