Liver and Pancreas Pathology Flashcards
What is the hepatic portal system?
2 consecutive capillary beds
First drain from the gut, second in the liver
Outline the anatomy of the gallbladder connecting the liver and duodenum
R and L hepatic duct = common hepatic duct
Cystic duct to gallbladder
Common bile duct + pancreatic duct = ampulla of vater
Join the 2nd portion of duodenum
What are the functions of the liver?
Metabolism
Storage = glycogen, lipoprotein, TGs
Protein prod = albumin, coag factors
Detox = CYP450, decrease drug efficacy
Bile production
Venous drainage of the gut goes where?
Portal vein —> liver
Briefly outline the structure of the liver
Portal vein from gut
Sinusoids to central canal
Hepatocytes
Bile canaliculus to bile duct
Hepatic artery to sinusoids
Swelling of hepatocytes results in what?
Occlusion of sinusoids and bile canaliculus
What major vessels make up the portal system?
Portal vein = carrying nutrients
Hepatic artery = supplying oxygen to the liver
Outline RBC breakdown
Lifespan 120 days
Extravascularly in macrophages in spleen/liver
Bilirubin hydrophobic so needs to be bound to albumin – carried to liver
In liver – conjugated with glycoronic acid by UDP glucuronyl transferse
Conjugated bilirubin = water sol
Secreted by hepatocytes into bile canaculi
Released into duodenum
Converted to urobilinogen
1) bacteria convert to stercobilin - excreted in faeces
2) absorbed back int the bloodstream, goes to kidneys, excreted as urobilin
Broadly speaking how do we measure liver dysfunction
Failure of anabolism
Failure to catabolise and excrete
Marks of hepatocyte damage/dysfunction
Hypoalbuminaemia reflects what?
Severe liver dysfunction
What can a prolonged prothrombin time reflect?
Significant liver dysfunction = failure to prod coag factors
Explain how jaundice can reflect liver pathology
Bilirubin conjugated for removal by the liver
This step is unable to take place when liver damage is present
= bilirubin still present = build up = jaundice
What are the types of jaundice?
Pre-hepatic = too much bilirubin (haemolytic anaemia)
Intra-hepatic = failure to conjugate and/or secrete bilirubin (hepatitis, cirrhosis)
Post-hepatic = failure of biliary tree to convey the conjugated bilirubin to duodenum (biliary tree obstruction) (itching = pruritis)
What is cholestasis?
Decreased bile flow
How does bilirubin affect the urine?
Conjugated = water sol
If serum levels are raised = excreted in urine = dark yellow colour
Can be measured with dipstick
How does urobilinogen affect the urine?
Will not noticeably colour the urine
Can be measured with a dipstick
What is pruritis?
Itching
Build up of bile salts
Outline the signs and symptoms of pre-hepatic jaundice
Mild jaundice
V.dark stools
Urine normal
No pruritis (as able to process bile salts)
On investigation what is seen in pre-hepatic jaundice?
Raised serum bilirubin (due to high RBC breakdown)
Increased urinary urobilinogen (due to high bilirubin being delivered to the gut)
No conjugated bilirubin in urine (kidney working fine)
Outline the signs and symptoms of intra-hepatic jaundice
Moderate jaundice
Normal stools
Dark urine (conjugated bilirubin)
No pruritis (as able to process bile salts)
On investigation what is seen in intra-hepatic jaundice?
Raised serum bilirubin (liver not working properly)
Normal urinary urobilinogen (kidney convert to urobilin)
Conjugated bilirubin in urine (some conjugated bilirubin not being secreted into the bile, goes to the blood, is water sol so arrears in the urine)
Outline the signs and symptoms of post-hepatic jaundice
Severe jaundice
Stools pale (low stercobilin in the gut as blocked bile release)
Urine dark (bilirubin)
Pruritis (retention of bile salts)
On investigation what is seen in post-hepatic jaundice?
Raised serum bilirubin (the liver outlet is blocked, it cant go anywhere so it appears in the blood)
Decreased urinary urobilinogen (not in the gut to go the the kidneys)
Conjugated bilirubin present in urine (water sol, present in the blood, excreted in the urine)
What are the markers of hepatocyte damage/dysfunction?
ALT = released by damaged hepatocytes
Alk Phos = present in bile duct and bone (high in young people due to high bone turnover)
GGT = present in bile duct and to lesser extent in hepatocytes
