Jaundice and Bilirubin Flashcards
(37 cards)
What is jaundice?
Yellow pigmentation of the skin or sclerae, caused by high levels of unconjugated or conjugated bilirubin in the blood
When is jaundice clinically apparent?
Plasma bilirubin concentration >50uM/L
Where is bile stored and concentrated?
Gallbladder
What causes bile to be released?
- CCK (cholecystokinin)
- Vagal response to food
What is bile composed of?
- Bile pigments (Hb breakdown products)
- Bile salts (derived from cholesterol and help emulsify fat)
What is bilirubin?
Hb breakdown product
Give an overview of bilirubin metabolism:
- Formed as a breakdown product of haemoglobin
- Conjugated in the liver to form a water-soluble molecule
- Extricated in the bile
- Metabolised in the gut by bacteria into urobilinogen and stercobilin
- Urobilinogen is reabsorbed and excreted in the liver
What is pre-hepatic jaundice?
Unconjugated hyperbilirubinemia
- Excess production of bilirubin that overtakes the ability of liver to conjugate the bilirubin and excrete into the gut
What can cause pre-hepatic jaundice?
o Haemolytic anaemia o RBC abnormality (sickle cell) o Incompatible blood transfusion o Drug reaction o Hypersplenism
What are the symptoms of pre-hepatic jaundice?
- Skin yellowing
- Pale urine
unconugated bilirubin is water-insoluble so does not enter urine - Dark stools (normal)
What is the reason for the symptoms in pre-hepatic jaundice?
- Liver function in patients with haemolytic jaundice is normal, but because of increased RBC breakdown, glucuronyl transferase is saturated.
- The liver compensates by increasing conjugated bilirubin output, making the stools dark (normal).
- This unconjugated bilirubin cannot be excreted in urine as it is not water soluble, so there is little/no bilirubin the urine causing pale urine
What is hepatic jaundice?
Conjugated and unconjugated hyperbilirubinemia
- Due to parenchymal liver disease (Intrinsic abnormality of the hepatocyte) with inability to either conjugate, uptake or excrete bilirubin.
What can cause hepatic jaundice?
- Congenital
- Acquired
Infection (viral hepatitis)
Cirrhosis (alcohol)
Cirrhosis (NASH)
Damage by toxins or drugs
What are the symptoms of hepatic jaundice?
- Skin yellowing
- Variable Dark urine
- Variable Pale stools
In hepatocellular damage what would the LFTs show?
INCREASED:
- ALT (markedly)
- AST
- GGT
- Bilirubin
- Alk. phos (mildly)
- INR
Rise in ALT, AST»_space; rise in alk phos
DECREASED:
- Albumin
What would you find on examination with hepatic jaundice?
- Dull RUQ pain
- US: liver enlarged/shrunken with or without splenomegaly
What is post-hepatic jaundice?
An impediment to the flow of bile due to a partial or complete obstruction of the extrahepatic biliary passage between the liver and duodenum.
What can cause post-hepatitc jaundice?
• Obstruction of bile duct by stone
• Obstruction of bile duct by tumour
Head of pancreas
Cholangiocarcinoma
Lymph Node metastasis
• Also consider intra-hepatic cholestasis
Primary biliary cholangitis
Primary sclerosing cholangitisWhat is cholestasis?
A decrease in bile flow due to impaired secretion by hepatocytes or to obstruction of bile flow through intra-or extrahepatic bile ducts.
What are the symptoms with post-hepatic jaundice?
- Skin yellowing
- Dark urine
Liver fucntion is normal, so bile is conjugated - Pale stools
No bilirubin in intestine
In post-hepatic jaundice what would the LFTs show?
INCREASED:
- ALT (mildly)
- AST
- ALP (markedly)
- INR (maybe)
can be correctable with Vitamin K
- Bilirubin
Rise in ALT, AST «_space;rise in alk phos
UNCHANGED:
- Albumin
What would you find on examination with post-hepatic jaundice?
- Colicky RUQ pain
Pain that stops and starts abruptly - US/CT: cholelithiasis, dilated biliary tree, SOL (space occupying lesions), gallbladder stones
- Pruritis
When is neonatal jaundice detectable?
Serum bilirubin > 85 micromoles/litre
Which type of jaundice is more common in newborns?
Unconjugated hyperbilirubinaemia
