liver Flashcards
what vessels supply blood to the liver
- hepatic artery - branch of the coeliac axis (25%)
- portal vein - drains most of the GI tract and spleen (75%)
what is the network between hepatocytes
bile canaliculi which join to form thin bile ductules near the portal tract which in turn enter bile ducts in the portal tracts
- the hepatic ducts join at the porta hepatitis to form the common hepatic duct
what connects the gall bladder to the lower end of the common hepatic duct
cystic duct
what does the gallbladder store
It lies under the right lobe of the liver and stores and concentrates hepatic bile - it has a capacity of 50ml
what forms the central bile duct
cystic and hepatic ducts, narrowing at its distal end to pass into the duodenum
- the CBD and pancreatic duct open into the 2nd part of the duodenum through a common channel at the ampulla of vater
where is the liver found
the right hyporchondrium
how many segments make up the liver
8 - each segment has its own portal pedicle, permitting individual resection at surgery
what are sinusoids
low pressure vascular channels that receive blood from terminal branches of the hepatic artery and portal vein at the periphery of lobules and deliver it into central veins.
what is the caudate lobe
independent part of the liver, supplied by the right and left hepatic artery and portal vein. Blood from the caudate lobe drains directly into the vena cava
what is the acinus
the functional hepatic unit which consists of parynchyma supplied by teh smallest portal tracts containing portal vein radicals, hepatic arterioles and bile ductules
what is jaundice
Jaundice is a condition in which the skin, whites of the eyes and mucous membranes turn yellow because of a high level of bilirubin, a yellow-orange bile pigment.
when is jaundice detectable clinically
when serum bilirubin is over 50 umol/L
what can jaundice be divided into
- haemolytic jaundice
- congenital hyperbilirubinaemia
- cholestatic jaundice
what is haemolytic jaundice
Increased bilirubin load for the liver cells due to increased breakdown of RBCs
- usually mild jaundice
what causes haemolytic jaundice
Haemolytic anaemia
clinical features of haemolytic jaundice
- jaundice
- splenomegaly
- gallstones
- leg ulcers
what is congenital hyperbilirubinaemia
defects in conjugation
what is unconjugated bilirubin
not water soluble and therefore doesn’t pass into the urine
Acholuric jaundice = Jaundice without bile pigments in the urine.
what are unconjugated types of jaundice
- Gilberts syndrome
- Crigler-Najjar syndrome
what are conjugated types of jaundice
- Dubin-Johnson and Rotors syndromes
- Benign recurrent intrahepatic cholestasis
- Progressive familial intrahepatic cholestasis syndromes
what is cholestatic jaundice (acquired)
cholestatic, or obstructive, jaundice, occurs when essentially normal liver cells are unable to transport bilirubin either through the hepatic-bile capillary membrane, because of damage in that area, or through the biliary tract, because of anatomical obstructions such as gallstones or cancer.
what is extra hepatic cholestasis
due to a large duct obstruction of bile flow at ant point in the biliary tract distal to the bile canaliculi
what is intra hepatic cholestasis
occurs because of the failure of bile secretion, which may be caused by intrinsic defects in bile secretion of inflammation in the intrahepatic ducts
what causes extra hepatic cholestasis
- common duct stones
- Carcinoma in the bile duct, head of pancreas or ampulla
- Biliary stricture
- Sclerosing cholangitis
- Pancreatic pseudocyst
what causes intra hepatic cholestasis
- viral hepatitis
- drugs
- alcohol
- cirrhosis
- autoimmune cholangitis
what are the signs and symptoms of extra and intra hepatic cholestasis
- jaundice
- pale stools
- dark urine
- serum bilirubin is conjugated
what are the 2 most useful tests for jaundice
- viral markers ( for HAV, HBV, HCV )
- ultrasound - to exclude an extra hepatic obstruction and to diagnose any features comparable with chronic liver disease
what is acute liver failure
acute liver injury with encephalopathy and deranged coagulation (INR>1.5) in a patient with a previously normal liver
what causes acute liver failure
- viruses
- drugs eg paracetamol, antibiotics, antidepressants
- toxins
- hepatic failure in pregnancy
- vascular causes
- metabolic causes
- malignancies
what are clinical features of acute liver failure
- jaundice
- small liver
- signs of hepatic encephalopathy
- Fetor hepaticus
- fever
- vomitting
- hypotension
- hypoglycaemia
- spascitiy
- cerebral oedema
what investigations should be carried out for acute liver failure
- routine tests
- there is hyperbilirubunaemia, high serum aminotransferases and low levels of coagulation factors . Aminotransferases are not useful indicators of the course of the disease as they tend to fall along with the albumin with progressive liver damage
- an electroencephalogram is sometimes helpful in grading encepathology
- ultrasound will define size of liver and may indicate underlying liver pathology
management of acute liver failure
- no specific treatment
- supportive therapy
- 20% mannitol if increased intracranial pressure
- suspected infection = antibiotics
- transplant
what is autoimmune hepatitis
Inflammatory liver disease of unknown cause characterized by suppressor T cell defects with autoantibodies directed against hepatocyte surface antigens. Type 2: children and young adults, type 1: adults
signs and symptoms of autoimmune hepatitis
Most present with autoimmune signs: fever, malaise, urticarial rash, polyarthritis, pleurisy, pulmonary infiltration or glomerulonephritis. Also may present with signs of chronic liver disease
what are investigation findings for autoimmune hepatitis
Raised AST, ALT, serum bilirubin and Alk Phos, hyper gammaglobulinaemia (esp IgG), positive autoantibodies
how to manage autoimmune hepatitis
- prednisolone daily for at least 2 weeks followed by a slow reduction to a maintenance dose
- Azathrhioprine should be added as a steroid sparing agent
