Jaundice Flashcards
Note- More useful cards on approach to jaundice in AIP section
How can jaundice be classified?
By the site of the issue causing the jaundice:
Pre-hepatic- e.g. Haemolysis
Hepatic- e.g. Hepatitis, AFLD
Post-Hepatic/Obstructive- Cholecystitis
Note- Alternatively can be classified as to wether there is elevated conjugated or unconjugated bilirubin
Which form of bilirubin is lipid soluble/not water soluble?
Unconjugated bilirubin- it is not water soluble so does not enter the urine
Conjugating bilirubin allows it to be excreted in the urine as this form is water soluble
What is the role of hepatocytes in bilirubin metabolism?
Hepatocytes are responsible for conjugating bilirubin, forming water soluble conjugated bilirubin
Where is conjugated bilirubin excreted into from hepatocytes?
Into the bile, which drains via bile canaliculi and then into bile ducts to the Gall Bladder where it is stored
How is bile released from the Gall Bladder? (what route and what triggers it)
Bile is released from the gall bladder after eating, it plays a role in emulsifying fat to improve digestive processes
It is released into the duodenum at Ampulla Vater (formed by the union of the common hepatic duct and pancreatic duct)
What happens to conjugated bilirubin in the GI tract?
Converted to urobilinogen- some is then re-absorbed into the blood and is excreted in the urine. The rest is converted to sterobilin which is excreted in the faeces- makes the poo brown
What is an early sign of hyper bilirubinaemia?
Yellowing of the sclera
What are some causes of jaundice due to raised un-conjugated bilirubin?
Unconjugated bilirubin is not excreted in the urine so the urine of these patients will not appear darker than usual.
Increased red cell break down- Haemolytic anaemias, Ineffective Haematopoeisis (leading to breakdown by macrophages- e..g. Sickle Cells
Increased production- Infective erythropoiesis, Malaria
Impaired hepatic uptake- Drugs (paracetamol/rifampicin)- Ischaemic Hepatitis
Impaired conjugation- Gilbert’s (UGT enzyme defective, causes harmless transient jaundice with stress on body). Crigler Najjar syndrome- no UGT at all leads to high levels of unconjugated bilirubin- usually fatal due to brain damage
What are some hepatic causes of jaundice?
Cirrhosis Viral Hepatitis HCC Enzyme defects- Gilbert's, Crigler-Najjaar Fatty Liver Disease- Alcoholic or non-alcoholic Drugs Wilson's Disease- causing liver injury Liver metastases Auto-immune hepatitis
What are some post hepatic causes of jaundice?
Cholecystits Pancreatic Cancer- Head of the pancreas, must rule out if painless jaundice Primary biliary cholangitis Primary sclerosing cholangitis Cholangiocarcinoma
What is an important consequence of bile outflow obstruction?
Fat malabsorption which results in impaired absorption of fat soluble vitamins (A, D, E K)- vital for clotting and bleeding is a big risk
Causes fatty, pale stools
What are the most common type of gall stones?
Cholesterol stones- 75-90%. Pale in colour. May also contain calcium carbonate so are sometimes visible on X-Ray (Not always)
Pigmented Stones- Smaller amounts of bilirubin stones which are dark and pigmented
Brown stones- sign of infection in the gall bladder/bile ducts. Typically E.Coli.
What type of gall stones are usually visible on X-Ray?
Bilirubin stones as they normally contain calcium too (Calcium bilirubinate). Formed from un-conjugated bilirubin.
What are some risk factors for gall stones?
Female
Fat (Obesity)
Fertile (Pregnancy)
Forty (Increasing age)
What is a gallstone ileus?
Gall stone in the cystic duct prevents outflow of bile. This leads to cholecystitis- inflammation and distention of the gall bladder occurs. Inflamed walls of the gall bladder press on the small bowel and inflammatory process causes there to be a fistula formed between gall bladder and small bowel. Large stones can then pass into the bowel and cause an ileus- impacting in the GI tract typically at terminal ileum/ileocoecal valve leading to obstruction
