Jaundice

Question 1

What is jaundice?

Answer 1

Yellow discolouration of the skin and sclera due to increased plasma bilirubin

Question 2

Bilirubin metabolism
1) What is bilirubin conjugated with in hepatocytes?
2) How does bilirubin change after conjugation?
3) How does post-conjugated bilirubin enter the gut?
4) Some of this bilirubin is taken up by the liver again - what happens to the rest?
5) From this point, what are the 2 things that can happen to the ‘rest’?

Answer 2

1) Glucuronic acid
2) Is now water soluble
3) In bile
4) Converted to urobilinogen by gut bacteria
5) Reabsorbed and excreted by the kidneys, or converted into stercobilin which is excreted in the faeces and colours it brown

Question 3

Prehepatic jaundice
1) Do prehepatic causes of jaundice result in conjugated or unconjugated hyperbilirubinemia?
2) Is bilirubin in this form soluble or insoluble in water, and what is the relevance of this?
3) What are the 2 main mechanism that cause prehepatic jaundice?
4) Name a cause of each of these 2 main mechanisms

Answer 3

1) Unconjugated hyperbilirubinemia
2) Insoluble - doesn’t enter urine
3) Excessive erythrocyte breakdown and dysfunctions of conjugation
4) Excessive erythrocyte breakdown - haemolytic anaemias, malaria
Dysfunctions of conjugation - Gilbert’s disease and Crigler-Naajjar

Question 4

Hepatic jaundice
1) Do hepatic causes of jaundice result in conjugated or unconjugated hyperbilirubinemia?
2) What are the 2 main mechanism that causes this type of jaundice?
3) Name 4 causes of these mechanism
4) Name 2 features that are different between hepatic and prehepatic jaundice due to the difference in whether bilirubin is conjugated or not

Answer 4

1) Conjugated (can also be unconjugated)
2) Liver impairment results in hepatocytes that can’t conjugate bilirubin or there is too much pressure within the liver causing a backlog of conjugated bilirubin into the blood
3) Viruses (hepatitis, CMV, EBV), drugs i.e. paracetamol overdose, halothane, valproate, statins, tuberculosis antibiotics, alcohol, liver cirrhosis, liver carcinoma, haemochromatosis, autoimmune hepatitis, alpha-1 antitrypsin deficiency, Budd-Chiari syndrome, Wilson’s disease, failure to excrete conjugated bilirubin (Rotor and Dubin-Johnson syndromes)
4) In hepatic jaundice: bilirubin in urine, high AST and ALT levels, darker urine, paler stools

Question 5

Post hepatic jaundice
1) Do posthepatic causes of jaundice result in conjugated or unconjugated hyperbilirubinemia?
2) What is the mechanism that causes post hepatic jaundice?
3) Name 2 causes of post hepatic jaundice

Answer 5

1) Conjugated
2) The pathway of conjugated bilirubin in the biliary tree is obstructed causing it to seep into the bloodstream
3) Gallstones, pancreatic tumour, cholangiocarcinoma, primary biliary cholangitis, primary sclerosing cholangitis, Caroli’s disease, drugs i.e. co-amoxicillin, flucloxacillin, steroids

Question 6

How is jaundice managed?

Answer 6

Treatment of the cause