Jaundice Flashcards
What is Jaundice?
Yellow discouloration of the sclera and skin due to hyperbilirubinemia
What Bilirubin level causes jaundice?
Greater than 50µmol/L
How is Bilirubin made?
It is a breakdown product of Haem and so it is formed from the destruction of red blood cells
Where is Bilirubin Conjugated?
The liver
What happens to bilirubin when it is conjugated?
It becomes water soluble
How is bilirubin normally excreted?
In bile via the GI tract
In what form is Bilirubin digested in faeces?
As urobiliogen and Stercobilin
How much of urobilogen reabsorbed into the blood stream?
10%
What happens to the Urobilogen reabsorbed into the blood stream?
Excreted via the kidneys
What causes Pre-Hepatic jaundice?
excessive red blood cell breakdown which will overwhelm the liver and its ability to conjugate bilirubin causing high levels of unconjugated bilirubin
What are some examples of Pre- Hepatic Jaundice? (3)
Haemolytic anaemia, Gilberts syndrome, Criggler Najjar Syndrome
What is Hepatocellular Jaundice?
dysfunction of the hepatic cells
The liver will lose the ability to conjugate bilirubin causing and increase in unconjugated bilirubin
If the liver is also cirrhotic it may compress the intra-hepatic portions of the biliary tree which will cause some obstruction
This will cause a mixture of conjugated and unconjugated bilirubin
What are some examples of Hepatocellular Jaundice? (8)
Alcoholic liver disease, Viral hepatitis, Latrogenic (medications) Hereditary haemochromatosis, Autoimmune hepatitis, Primary biliary cirrhosis or primary sclerosing cholangitis, Hepatocellular carcinoma
What is Post-hepatic Jaundice?
Obstruction of biliary drainage
Bilirubin is therefore not excreted leading to increased conjugated bilirubin
What are some examples of Post- hepatic Jaundice? (5)
Intraluminal causes e.g. gallstones, Mural causes e.g. Cholangiocarcinoma, strictures or drug induced cholestasis, Extra mural causes such as pancreatic cancer or abdominal masses e.g. lymphomas
Which type of jaundice causes dark urine and pale stools?
Post hepatic due to the high levels of conjugated bilirubin which is water soluble and excreted in urine and low levels of stercobilin entering the GI tract
What blood test is most important in Jaundice?
LFTs
What do Bilirubin levels show?
the degree of Jaundice
What does Albumin show?
Liver synthesising function
What does AST and ALT show?
Markers of hepatocellular injury
What is the most likely cause if AST:ALT ratio >2?
Alcoholic liver disease
What is the most likely cause if AST:ALT ratio is around 1?
Viral hepatitis
What does Alkaline phosphatase show?
Raised in biliary obstruction but also bone disease, pregnancy and malignancy
What does Gamma GT show?
Specific to biliary obstruction
