Jaundice and chronic liver disease (not done) Flashcards
What are the basic functions of the liver?
Synthesis
Detoxification
Immunity
Storage
What does the liver synthesize?
Clotting factors
Bile acids
Metabollites (carbs, lipids, proteins)
Hormones - Angiotensinogen, Insulin-like growth factor
What important protein is synthesized in the liver. Why is it relavent to GI?
Albumin
Low levels of albumin can indicate pathology of the liver and kidneys
What are the detoxification functions of the liver?
Turning ammonia into urea
Detoxification of drugs
Billirubin metabolism
Breakdown of insulin and other hormones
Highlight the immune functions of the liver
- Combating infections
- Clearing the blood of particles and infections, including bacteria
- Neutralizing and destroying all drugs and toxins
What does the liver store?
Glycogen
Vitamins A, D, B12 & K
Copper
Iron
What are the different liver function tests?
Billirubin
Aminotransferases
Alkaline phosphotase
Gamma GT
Albumin
Prothrombin time
Creatinine
Platelet count
What is bilirubin?
By-product of Haeme metabolism
Produced in the spleen from old RBC’s
What is the purpose of Bilirubin testing?
Elevated as a result of:
- Pre-hepatic: Haemolysis
- Hepatic: Parenchymal damage
- Post hepatic: Obstructive
What are aminotransferases?
Enzymes that are present in hepatocytes
AST and ALT are both types of aminotransferase
What is the purpose of aminotransferase testing?
The ratio of AST:ALT can indicate Alcoholic liver disease (ALD)
Can suggest parenchymal involvement
What is alkaline phosphotase?
Enzyme present in bile ducts (+ bone, placenta and intestines)
What is the purpose of alkaline phosphotase testing?
Elevated with obstruction or liver infiltration
What is Gamma GT and why do we test for it?
Non specific liver enzyme
Levels are elevated by alcohol usage (also by NSAID usage)
Useful to confirm liver source of Alkaline phosphotase (ALP)
Why do we test for albumin levels?
Low levels suggest chronic liver disease
Can be low in kidney disorders and malnutrition
Why do we test the prothrombin time?
Extremely important test fo liver function as it shows the degree of liver dysfunction
For this reason, it is used to decide the stage of liver disease, who needs/gets a liver transplant
Why do we test for creatinine?
Determines survival chances from liver disease
Critical assessment for who needs a liver transplant
(technically shows kidney function not liver)
Why do we test for platelet count?
Platelet count is low in cirrhotic subjects as a result of hypersplenism
Indirect marker of portal hypertension
What are the symptoms of a failing liver?
- Jaundice
- Ascites
- Variceal bleeding
- Hepatic encephalopathy
What is jaundice?
Yellowing of the skin, sclerae, and other tissues caused by excess circulating bilirubin
How much bilirubin is needed for jaundice to be detectable?
Detectable when total plasma bilirubin levels exceed 34 µmol/L
What is a differential diagnosis for jaundice?
Carotenemia
(increased beta-carotene levels in the blood due to diet)
What is the intermediate between Haeme and Bilirubin?
Biliverdin
What is the difference between Pre-hepatic, hepatic and post hepatic bilirubin?
Pre-hepatic - Bilirubin is unconjugated and is complexed with albumin (in blood)
Hepatic - Bilirubin conjugates with glucuronic acid
Post-hepatic - Conjugated bilirubin in bloodstream
Increased quantity of bilirubin (jaundice) that is PRE-hepatic indicates what?
Increased quantity of bilirubin - as a result of Haemolysis
or
Impaired transport
What does increased hepatic levels of bilirubin indicate?
Defective uptake of bilirubin
Defective conjugation
Defective excretion
Increased post hepatic levels of bilirubin is an indicator of what?
Defective transport of bilirubin by the biliary ducts
What features on a history would indicate pre-hepatic jaundice?
H/o Anaemia
Acholuric jaundice (inherited condition)
What features on a history would indicate hepatic jaundice?
Risk factors for liver disease (IVDU, drug intake)
Decompensation (ascites, variceal bleed,encephalopathy)
What features on a history would indicate post-hepatic jaundice?
Abdominal pain
Cholestasis (Pruritus, pale stools, high coloured urine)
What clues on clinical examination would indicate pre-hepatic jaundice?
Pallor
Splenomegaly
What clues on clinical examination would indicated hepatic jaundice?
Stigmata of CLD (spider naevi, gynaecomastia)
Ascites
Asterixis (liver flap)
What features on clinical examination would indicate post-hepatic jaundice?
Palpable gall bladder (Courvoisier’s sign)
What investigations would you do for jaundice?
Abdominal US scan
Liver screen:
- Hepatitis B & C serology
- Autoantibody profile, serum immunoglobulins
- Caeruloplasmin and copper
- Ferritin and transferrin saturation
- Alpha 1 anti trypsin
- Fasting glucose and lipid profile
Why is an abdominal ultrasound scan useful for jaundice?
- Differentiates extrahepatic and intrahepatic obstruction
- Delineates site of obstruction
- Delineates cause of obstruction
- Documents evidence of portal hypertension
- Preliminary staging of extent of disease e.g. cancer spread
