Disorders of the liver, biliary system and pancreas Flashcards
What are the three broad functions of the liver?
Filter: absorbs venous blood from the intestines via the portal vein Excretion: removes unnecessary metabolites via the bile duct Metabolism: secretes useful nutrients into the systemic circulation via the hepatic vein
What clinical sign is the hallmark of liver failure?
Metabolic flap caused by hepatic encephalopathy
What is the cause of acute liver injury and how does it present?
Acute injury caused by sudden trauma or insult e.g. Drug overdose, physical trauma Normally presents as a disturbance in the metabolic functions of the liver e.g. Acidosis, renal failure (sometimes jaundice)
What are the causes of chronic liver disease and how does it present?
chronic liver disease is caused by long standing low grade damage, for example one or more insults that cause persistent inflammation. Damage normally compromises all the liver’s main functions.
How does decompensation affect liver disease?
Decompensation in patients with chronic liver disease occurs due to secondary influences or illnesses which cause a steep decline in liver function E.g. Infection, dehydration, drugs, bleeding This exposes the livers weakness and ‘lack of reserve’ However in most cases with treatment function can be restored.
Name 3 common complications and effects of cirrhosis
Ascites Portal hypertension (intrahepatic) Renal failure
Describe the factors that lead to ascites
Ascites is the build up of fluid in the peritoneal cavity. Peripheral arterial vasodilation causes a reduction in effective blood volume promotes salt and water retention in the kidneys In patients with liver disease there low serum albumin which reduces plasma oncotic pressure Portal hypertension exerts a hydrostatic pressure that causes increased production of lymph and transudation of fluid into the peritoneal cavity.
describe the features of biliary colic
Pain associated with the temporary obstruction of the common or cystic bile duct by a gallstone. Pain is characterised as severe, constant crescendo. Normally associated with eating fatty foods.
Describe the mechanism of obstructive jaundice
Obstructive jaundice is extra-hepatic and is caused by a large obstruction of bile flow in the biliary tract, normally in the common bile duct.
Inability of the gall bladder to secrete bile results in an excess of bilirubin, which is absorbed into the blood. Some is excreted by the kidneys but increasing levels in the blood result in jaundice.
Describe the differences between acute and chronic pancreatitis
Acute pancreatitis:
Sudden onset of acute epigastric pain and radiates to the back.
Raised serum amylase (x3)
90% of cases caused by gall stones and/or alcohol
Necrotising pancreatitis - Grey Turner’s sign/Cullens sign
Most patients make a full recovery
Chronic pancreatitis:
Presents as episodic/constant epigastric pain that radiates to the back. Anorexia and weight loss
Serum amylase is often normal
Mostly caused by alcohol
Chronic inflammation causes a loss of acini which is replaced by fibrosis. Commonly causes pseudocyst formation.
List 6 potential causes of acute pancreatitis
gall stones
ethanol (alcohol)
trauma
steroids
mumps
autoimmune
scorpion sting
hyperlipidemia
ecrp
drugs
What blood tests would you do to test for liver distress?
Aminotransferases: ALT/AST
These are present in hepatocytes and leak into the blodo when there is liver cell damage. ALT is more specific to the liver and only rises with liver disease. AST is also present in the heart, muscle, kidney and brain
Alk Phos/ gamma-GT
Alk Phos is present in canalicular and sinusoidal membranes of the liver but also in other tissues, raised in cholestasis, jaundice and metastases. gamma-GT is present in many tissues and activity is induced by alcohol. Raised ALT/gamma-GT indicates cholestasis
What blood tests are used to assess liver function?
Serum albumin:
This is a marker of synthetic function, and indicates the severity of chronic liver disease
Prothrombin time:
Measure of how long it takes for blood to clot. Prothrombin synthesised in the liver, therefore is a sensitive indicator of acute and chronic liver disease. An abnormal prothrombin time is often caused by liver disease or injury or by treatment with blood thinners.
Others:
Bilirubin: increased serum bilirubin in liver disease
Urea: Low blood urea nitrogen could indicate liver damage
What is included in a liver screen and why is it carried out?
Liver screens are used to help determine the cause of liver disease
Infection: viral markers (HAV, HBV, HCV)
Metabolic:
Serum and urinary copper (Wilsons), iron (haemochromatosis)
a1-antitrypsin deficiency (cirrhosis)
Inflammatory: Raised serum Ig
autoimmune hepatitis
primary biliary cirrhosis
primary sclerosing cholangitis
Malignancies
Name two tests which are used to assess the endocrine and exocrine functions of the pancreas
Endocrine:
Blood glucose
Glucose tolerance test
Exocrine:
PABA test - chemical hydrolysed to p-aminobenzoic acid by chymotrypsin which is conjugated and excreted in the urine.
Pancreolauryl test - fluorescein dilaurate is digested by pancreatic esterase to fluorescin which is excreted in the urine
Faecal elastase: pancreatic enzyme not degraded in the small intestine and normally has high levels.
