S7 Liver And Pancreas Pathology Flashcards
What are the functions of the liver?
Metabolism of proteins and lipids
Detoxification
Synthesis of bile and albumin
Stores glycogen
Describe bile flow from the gallbladder to the duodenum
From the gallbladder, bile enters the cystic duct, then the common bile duct, then the ampulla of vater
What is found in the portal triad?
Portal vein, hepatic artery, bile duct
What are kupfer cells?
Specialised cells lining sinusoids containing many macrophages, making them an efficient detoxifying system.
Outline the production of bilirubin
Bilirubin is the breakdown product of haem.
Unconjugated bilirubin is bound to albumin and carried to liver where it is conjugated with glucoronic acid.
Conjugated bilirubin then passes into colon where it is metabolised into urobilinogen, then oxidised to stercobillin and urobillin
What is jaundice?
Yellow discolouration of skin due to high levels of bilirubin
Describe the features of pre-hepatic jaundice
Caused by Increased levels of haem/bilirubin (e.g from haemolytic anaemia)
Liver cannot conjugate it so raised levels of unconjugated bilirubin
results in Mild jaundice (pale yellow), only one with normal light urine
Describe the features of intra-hepatic jaundice
Caused by reduced liver function (e.g cholestasis)
Contains both unconjugated and conjugated bilirubin
Moderate jaundice (orange yellow)
High AST and ALT
Describe the features of post-hepatic jaundice?
Caused by obstruction to bile drainage into duodenum (e.g. gallstones)
Raised levels of conjugated bilirubin
Severe jaundice (green yellow)
High ALP
What is the role of liver function tests?
Indicate liver DAMAGE rather than function.
Describe albumin as an LFT
Made by the liver,
Hypoalbuminaemia shows reduced liver function.
Will cause oedema as less oncotic pressure so fluid leaks
Describe prothrombin time (INR) as an LFT
Increased time indicates reduced liver function as fewer clotting factors
Name 3 hepatic enzymes used in LFTs
ALT
AST
ALP
Describe ALT as an LFT
Increased following hepatocyte damage, e.g. toxins, alcohol.
More specific for liver dysfunction than AST
Describe AST as an LFT
Increased following hepatocyte damage, but also found in cardiac and skeletal muscle, so ALT more specific to liver
However in alcoholic liver disease and cirrhosis; AST>ALT
Describe ALP as an LFT
Found in cells lining bile ducts (canaliculi), so increased in bile duct obstruction (cholestasis).
NB also increased in bone disease and pregnancy. Can do Gamma GT to specify if ALP raised from liver damage or other cause.
What imaging method is best for liver disease?
Ultrasonography
What is hepatitis and what is it caused by?
Inflammation of the liver due to hepatocyte inflammation or breakdown.
Caused by alcohol or drug use.
What is the effect of hepatitis on the liver?
Liver fibrosis produces a shrunken hard nodular liver. This leads to replacement of hepatocytes by fibrous tissue causing reduced albumin and clotting factor production.
What are the symptoms of hepatitis?
RUQ pain
Jaundice
Fever
What do blood tests show in hepatitis?
Normal albumin, high bilirubin, high ALT, normal ALP
What is cirrhosis and how does the liver appear?
Chronic irreversible liver disease.
Hepatocyte necrosis causes nodular regeneration and fibrosis.
What are the symptoms of cirrhosis?
Ascites, swollen legs, jaundice, weight loss.
What may blood tests show in cirrhosis?
Low albumin, prolonged INR, raised ALT/ALP.
What is the treatment for cirrhosis?
Liver transplant
How does alcoholic liver disease cause cirrhosis?
Alcohol first causes fatty change, then alcoholic hepatitis, then eventually cirrhosis (only irreversible one).
Hep B/C can cause cirrhosis. What is it also a risk factor for?
Hepatocellular carcinoma
How does fatty liver disease cause cirrhosis? (Non alcoholic)
Accumulation of triglycerides causes fatty change then cirrhosis
How does Hereditary haemochromatosis cause cirrhosis?
Abnormal iron metabolism where excess iron is deposited in regions such as liver
How does Wilson’s disease cause cirrhosis?
Abnormal copper metabolism where reduced copper secretion causes accumulation is tissues and liver. Get kayser-fleishcer ring around eye
How does Primary sclerosing cholangitis cause cirrhosis?
Through fibrosis of intra or extrahepatic bile ducts.
Usually in men
Causes high ALP and presence of ANCA
How does primary biliary cirrhosis cause cirrhosis?
Destruction of intrahepatic ducts.
Usually in women
Causes high ALP and presence of AMAs
How does cirrhosis cause portal hypertension?
Cirrhosis leads to PH due to the build-up of blood in the portal venous system and compression of veins
How does cirrhosis cause ascites?
In cirrhosis, the fibrotic liver cannot expand much and compresses e.g the portal vein.
This causes increased hydrostatic pressure, which coupled with low oncotic pressure (reduced albumin synthesis) leads to ascites
How does portal hypertension lead to varices (porto-systemic anastomosis)?
Blood shunts from the portal system to systemic circulation causing distension of veins there resulting in varices
Describe oesophageal varices
Enlarged submucosal veins as more blood goes to azygous/left gastric veins
Describe umbilical varices (caput medusa)
Shunt of blood from the portal vein to umbilicus via the ligamentum teres
Describe rectal varices
Occurs between superior, middle and inferior rectal veins, can cause haemorrhoids
What is hepatorenal syndrome?
Development of AKI in the presence of cirrhosis.
How does cirrhosis cause hepatorenal syndrome?
Portal hypertension causes arterial vasodilation and activation of RAAS. This causes renal artery vasoconstriction and consequently less kidney perfusion
What can cause biliary duct obstruction?
Gallstones
Carcinoma of the head of the pancreas
How are gallstones formed?
Abnormal concentrations leading to precipitation of bile constituents
What is a biliary colic?
Temporary obstruction of gallstone in cystic or common bile duct.
Precipitated by eating a fatty meal, causes RUQ pain, no inflammation.
What is cholecystitis?
Inflamed gallbladder due to gallstone in cystic duct. Causes severe RUQ pain and tenderness over gallbladder.
What is cholangitis?
Infection of bile duct (E. Coli) from obstruction by gallstone.
Present with pain, inflammation and jaundice (Charcot’s triad)
How can liver metastases occur?
Liver filters blood, cancer cells can lodge this filter. Hepatic artery and portal vein can get blocked.
What is acute pancreatitis?
Premature activation of pancreatic proteases which autodigest the pancreas.
What can cause acute pancreatitis?
Gallstone in ampulla of vater
Alcohol
What are the symptoms of acute pancreatitis?
Epigastric pain that radiates to the back, vomiting
Which lab tests are used to diagnose pancreatitis?
Raised serum amylase
What is chronic pancreatitis?
Due to acute pancreatitis leading to pancreatic fibrosis.
Caused by alcohol abuse.
Pancreas becomes calcified causing severe epigastric and back pain.
What is the most frequent pancreatic cancer type and presentation?
Ductal adenocarcinoma.
Symptoms later develop showing obstructive jaundice, epigastric/back pain, weight loss.
