Jaundice Flashcards
Define biochemical hyperbilirubinaemia
more than the upper limit of normal for the biochemical reference range for bilirubin levels
Define jaundice
clinical manifestation of hyperbilirubinaemia detected by a change of scleral and skin colour
When is jaundice sclera/skin generally visible
biliribin >50 micromol/L
What are howell-jolly bodies?
inclusions of nuclear chromatin remnants
What are heinz bodies?
inclusions of denatured haemoglobin caused by oxidative damage
What are siderocytes?
RBC containing granules of iron that are not part of the cell’s haemoglobin
What are pappenheimer bodies?
inclusion bodies formed by phagosomes that have been engulfing excessive amounts of iron
Solubility of unconjugated (indirect) bilirubin
insoluble
(binds to albumen and is carried in blood)
Can indirect bilirubin appear in the urine?
no
Solubility of conjugated bilirubin
water-soluble
Can conjugated bilirubin appear in urine?
yes
Types of jaundice
pre-hepatic
hepatic
post-hepatic
Describe pre-hepatic jaundice
increase in blood unconjugated bilirubin (problem is with conjugation of bilirubin)
normal LFTs
no bilirubin in urine
no change in urine/faeces (NB haemoglobinuria in haemolysis)
Pre-hepatic jaundice causes
increased RBC breakdown - too much bilirubin delivered to liver
large haematoma
failure of hepatic conjugation (due to genetics - Gilbert’s)
Describe Gilbert’s syndrome
cause of pre-hepatic jaundice at times of stress
not harmful
no clinical problems
faulty function of UGT1
Describe Crigler Najjar syndrome
absent or nearly absent UGT1A1 enzyme activity
prevents shortly after birth with kernicterus
phototherapy
liver transplant
causes build up of unconjugated bilirubin in blood
What is kernicterus?
bilirubin-induced neurological damage
What is breast milk jaundice?
cause of unconjugated hyperbilirubinaemia in healthy newborns who are primarily breastfed
discontinuation of breast feeding and using formula rapidly corrects hyperbilirubinaemia
What is hepatic jaundice?
liver disease process affects the ability to both conjugate bilirubin and secrete the conjugated bilirubin into the biliary canaliculus
Causes of hepatic jaundice
acute liver injury
acute liver failure
chronic liver disease - cholestatic disease (before cirrhosis)
when a patient with cirrhosis develops decompensation
acute en chronic liver failure
Which type of bilirubin is high in hepatic jaundice?
mix of conjugated and unconjugated
Urine/faeces of those with hepatic jaundice
patients will excrete conjugated bilirubin into the urine and conjugated bilirubin will not enter the bowel
dark urine
pale stools
Clues that it might be hepatic jaundice
risk factors for liver disease
clinical signs of chronic liver disease
abnormal US - cirrhosis, ascites, portal hypertension, splenomegaly
other biochemical features of decompensated cirrhosis - prolonged PT, low albumen, low platelets
Cause of post-hepatic jaundice
bile duct obstruction
Complications of cholestasis
cosmetic
pruritis
fatigue/lethargy
increased energy requirements
vitamin ADEK
growth and hormonal disturbances
bone metabolism
Features of post-hepatic jaundice
bilirubin is conjugated
excreted into biliary system
cannot move to bowel due to obstructed flow of bile out of biliary system
cholangiocytes become leaky and bilirubin leaks into blood
no conjugated bilirubin enters bowel
Urine/faeces in post-hepatic jaundice
pale stools
dark urine (conjugated bilirubin enters urine)
What causes pruritis in post-hepatic jaundice?
bile salts not excreted into the bowel
Clues for post-hepatic jaundice
often due to cancers of bile duct or pancreas - weight loss + painless jaundice
raised AlkPhos + GGT
abnormal cross-sectional imaging - CT, MRI
painful obstructive jaundice - normally stone - US then MRCP
look for cholangitis
