5.2- Diseases of the Liver and Pancreas Flashcards
What 3 tests check liver function?
- Hepatocellular damage
- aminotransferases (ALT/AST)
- gamma glutamyl transpeptidase (y-GT)
- Cholestasis ( bile ducts)
- bilirubin
- alkaline phosphatase; suggests cholestasis or bone breakdown
- Synthetic function (APG)
- albumin
- prothrombin time (clotting)
- glucose
What is jaundice?
yellow pigmentation of the skin and sclera caused by accumulation of bilirubin in tissue
- clinically detectable when bilirubin>40umol/L
- normal range <22 umol/L
How do you classify jaundice?
1) Prehepatic ( haemolytic)
2) Hepatic (parenchymal)
3) Post-hepatic (cholestatic); backup of bilirubin in blood
What is the cause of jaundice?
disruption of the normal metabolism of bilirubin
May arise from any:
- Excessive bilirubin production because of increased haemolysis ( pre-hepatic)
- Reduced capacity of liver cells to secrete unconjugated bilirubin into blood; hepatic/intra-hepatic
- obstruction to drainage of bile, causing backup of bilirubin into liver ; post-hepatic
What is bilirubin?
- breakdown product of RBCs
- unconjugated biliirubin is bound to albumin in blood
- bilirubin is conjugated in the liver ie bound to glucoronic acid+becomes water soluble
- excreted in bile into duodenum
- de-conjugated into urobilinogen
- urobilinogen oxidised to form urobilin and stercobilin, which go into faeces
Once formed, what happens to urobilinogen?
- it gets oxidised in the duodenum to form urobilin and stercobilin, which leave in the stool
- trace of urobilinogen also gets reabsorbed into the eneterohepatic circulation:
and then re-excreted in bile
-also goes to kidneys and colour them yellow
What is pre-hepatic jaundice?
- because of excessive haemolysis due to anything
- liver is unable to cope with excess bilirubin
LAB FINDINGS:
1) Unconjugated hyperbilirubinaemia: (because bilirubin is unconjugated before it gets to the liver)
ie high amounts, is pre-hepatic jaundice
2) Reticulocytosis: immature RBCs (pre-hepatic jaundice)
3) Anaemia
What are the causes of pre-hepatic jaundice?
ie anything that causes haemolysis
- Inherited:
- RBC membrane defects
- Haemoglobinopathies eg sickle cell
- metabolic defects
- Congenital hyperbilirubinaemias
-Gilbert’s syndrome- common a lack of function in the enzyme that conjugates bilirubin
- Crigler-Najjar syndrome-rare
- Dubin Johnson syndrome-rare
- Acquired:
- immune
- mechanical
- infections
- drugs eg NSAIDS, cephalosporins, nitrafurantoin
What is hepatocellular jaundice?
ie hepatic/ intra-hepatic jaundice
- deranged hepatocyte function
- cell necrosis→inability to metabolise or excrete bilirubin
- happens w cholestasis ie slow sloppy movement of bile
What are the lab findings of hepatocellular jaundice?
- mix of unconjugated and conjugated hyperbilirubinaemia
- increased liver enzymes ie AST/ALT, reflects liver damage
- same or increased ALP; causes cholestasis and swollen cells (alkaline phosphatase)
- abnormal clotting
Name 9 causes of hepatocellular jaundice?
- Congenital
- Hepatic inflammation
- Autoimmune hepatitis
- Alcohol
- Drugs eg paracetamol
- Cirrhosis
- Hepatic tumours
- Haemochromatosis-depositions of Fe
- Wilson’s disease- depositions of Cu
What is post-hepatic/cholestatic/jaundice?
(OBSTRUCTIVE JAUNDICE)
- Obstruction of biliary system; can be intrahepatic or extrahepatic
- passage of conjugated bilirubin locked
What are the lab findings of post-hepatic/obstructive jaundice?
- conjugated hyperbilirubeinaemia
- bilirubin in urine ie dark ( bc of backup through liver intoblood; gets excreted into urine instead)
- pale stools ie steatorrhoea
- no urobilinogen in urine ie no bilirubin enters bowel so is not converted to urobilinogen
- increased canalicular enzymes ie ALP ( indicator of cholestasis/blockage of bile)
- raised ALT and AST bc of backing into liver
What are the causes of post-hepatic jaundice? ( Intrahepatic and Extrahepatic)
INTRAHEPATIC:hepatocyte swelling (HDCP)
- hepatitis
- drugs
- cirrhosis
- primary biliary cirrhosis
EXTRAHEPATIC: obstruction distal to bile canaliculi (GBC)
- gallstones
- biliary structure
- carcinoma in:
- head of pancreas
- ampulla
- cholangiocarcinoma ie bile duct
- porta hepatis lymph nodes
What is Courvoisier’s law for post-hepatic jaundice?
- in the presence of a non-tender palpable gallbladder, painless jaundice is unlikely to be caused by gallstones
- GB is often more enlarged when there is biliary obstruction over a shorter period of time eg malignancy
-tender GB seen in:
- acute cholecystitis; tender and distended w a mucocele or empyema related to gallstones
Recap: What are the 3 types of jaundice?
HOT LIVER
Pre-hepatic- Haemolytic
Hepatic- Obstruction
Post hepatic- cholestatic ie tumour
What is hepatitis?
- inflammation of the liver*
- can be acute or chronic
- Acute hepatocyte breakdown; causes Aminotransferase release (AST/ALT) and jaundice
- Prolonged/chronic damage:
- synthetic failure*
- low albumin*
- low clotting factors*
What are the causes of Hepatitis?
- infections-viral
- Toxins ie alcohol/haemochromatosis/ Wilson’s disease/drugs
- Autoimmune
What is viral hepatitis and what are the types?
- Hepatitis A:
-goes in via the faecal-oral route ie contaminated water+ usually acute
6F’s: faeces, flies fluid, field, fluids, fingers, food
- Hepatitis B:
- blood/body flluids/ vertical spread eg cervical transmission
- acute and chronic; may progress to cirrhosis
- Hepatitis C:
- blood spread
- involves chronic liver disease, cirrhosis and hepatocellular carcinoma
What are the different ducts near the liver and GB?
GB responsible for storage and passage of bile from liver to duodenum
Pathological processes which cano happen (OIIN)
- Obstruction
- Inflammation
- Infection
- Neoplasia
