jaundice Flashcards
what is physiological jaundice
Jaundice that begin day 2-3 and lasts for 10 day
What causes physiological jaundice
- more red blood cells with a shorter life span
- immature level unable to break down bilirubin
- immature gut means no bacteria to break down to urobillin meaning increased enterohepatic circulation
What is considered pathological jaundice
- <24hrs old
- rapid rise of bili >100
- sick newborn with jaundice
- serum bili >250 at 48hrs or >300 by 72hrs
- Failure to respond to phototherapy
- prolonged jaundice >14d in term and >21 in preterm
- cnjugated bili >35
- Pale, chalky stools and dark urine
What causes increase of bilirubin in the body
- ABO incompatibility
- inherited red cell membrane defects e.g. spherocytosis
- Erythrocyte enzymatic defects (G6PD] deficiency pyruvate kinase deficiency)
- sepsis
- polycythemia - macrosomia in diabetic mums
What causes a decreased clearance of bilirubin
Inherited defects in the gene that encodes UGT1A1
eg. Gilberts syndrome, Crigler-Najjar syndrome
What is Crigler Najjar syndrome
- disorder of bilirubin conjugation
- causes severe unconjugated hyperbilirubinemia
- can result in bilirubin-induced neurologic dysfunction
What inheritence pattern does Crigler Najjar syndrome have
rare, autosomal recessive
What causes Crigler-Najjar syndrome
absent or defective uridine diphosphate glucuronosyltransferase-1A1 (UGT1A1) enzyme
When do you suspect Crigler-Najjar syndrome
persistent unconjugated hyperbilirubinaemia
no underlying liver disease
no evidence of haemolysis
management of T1 Crigler Najjar syndrome
- avoid dehydration
- avoid medications that displace bilirubin
- chronic phototherapy
- liver transplant is curative.
what causes an acute exacerbation of crigler Najjar
- fasting
- infection
- hemolysis
- cholelithiasis
- cholecystitis
- general anesthesia.
What happens with an acute exacerbation of Crigler Najjar
- increase bilirubin production (hemolysis)
- reduce bile flow and bilirubin elimination (fasting, cholelithiasis, cholecystitis)
- and/or reduce plasma albumin
Management of acute exacerbation of Crigler Najjar
- intensive phototherapy
- albumin infusions
- plasmapheresis
management of T2 Crigler Najjar
phenobarbital
What is Gilberts syndrome
most common inherited disorder of bilirubin glucuronidation due to mutations in the UGT1A1 gene
What inheritence pattern is Gilberts syndrome
autosomal recessive
How do you diagnose Gilberts syndrome
hyperbillirubinaemia in the absence of haemolysis
What is breast milk jaundice
persistent benign hyperbilirubuniaemia beyond 2-3 weeks.
usually peaks within 2 weeks then resolves over 3-12 weeks
what is lactation failure jaundice
- inadequate intake of oral fluids and calorie intake resulting in weight loss + hypovolaemia
- Usually occurs in first week of life
- leads to hyperbilirubinaemia and sometimes hypernatraemia
What is kinicterus
- type of brain damage that can result from high levels of bilirubin
- can cause cerebral palsy and hearing loss.
what clinical signs would suggest a conjugated bilrubinaemia
dark urine
pale stools
What is biliary atresia
- extrahepatic bile ducts are obliterated by inflammation and subsequent fibrosis
- leading to biliary obstruction and jaundice.
- fatal if untreated
- unknown cause
what are the signs of biliary atresia
persistent jaundice (starts shortly after birth)
Pale stool
Dark urine
Failure to thrive
What investigation findings will you find in biliary atresia
- conjugated hyperbilirubinaemia
- GGT will be raised
What is usually the diagnostic method of choice for biliary atresia
histology by percutaneous biopsy
What is the medical management of biliary atresia
- antibiotics to prevent cholangitis.
- Ursodeoxycholic acid : encourage bile flow.
- Fat-soluble vitamin supplementation and nutritional suppor
What is the main surgical intervention for biliary atresia
Kasai portoenterostomy - usually performed before 8w old
If this fails, liver transplant
What is prolonged jaundice
> 14 days in term infant
>21 days in pre-term infant
What investigations should be done for prolonged jaundice
- conjugated and total serum bili
- FBC and blood film
- Blood group and DAT
- TFTs
- urine microscopy and culture
- urine for reducing substances
- LFTs
what is unconjugated bilirubin
produce of the breakdown of red cells, which circulates mostly bound to albumin.
Some is ‘free’ and able to pass to the brain
What is conjugated bilirubin
unconjugated bilirubin is metabolised in the liver to produce conjugated bilirubin which then passes into the gut and excreted in stool.
Small amount is re-absorbed in the enterohepatic circulation
Causes of prolonged unconjugated jaundice
- Haemolysis due to rhesus, ABO hereditary spherocytosis, enzyme deficiency (G6PD, pyruvate kinase)
- Brest milk jaundice
- infections inc. UTI
- endocrine - hypothyroid/hypopiruitarism
- metabolic causes - glucuronyl transferase deficiency/galactosaemia.
- sepsis
- liver disease
What causes breast milk jaundice
- dehydration
- poor gut motility
- failure to pass meconium
All increase enterohepatic circulation of bili.
Causes of prolonged conjugated jaundice
- intrauterine infection - TORCH
- biliary atresia
- neonatal hepatitis
- choledochal cyst
- parenteral nutrition
- Metabolic: CF/a1-antitrypsin/galactosaemia
- intrahepatic cholestasis - syndromic/familiar
