LFTs Flashcards
What is ALT?
Alanine aminotransferase
What is AST?
Aspartate aminotransferase
What is ALP?
Alkaline phosphate
What is GGT or Gamma GT?
Gamma glutamyl transferase
Which liver function markers indicate inflammation and why?
ALT and AST (aminotransferases)
Liver enzymes in hepatocytes which leak into the blood stream when liver cells are damaged.
High in hepatitis
Which amino transferase is more specific to the liver?
ALT as AST can be raised in muscle damage
Where is ALP found?
Enzyme mainly in the bile ducts of the liver
What does and increase in ALP suggest regarding the liver?
Obstructive or cholestatic disease
ALP can also be raised in bone disease. What additional enzyme can be tested along with ALP to check the problem is liver related?
GGT will also be raised with ALP if its a liver problem.
What can cause a low albumin?
Chronic liver disease- especially if it is getting worse.
Proetin deficiency
Which clotting factors are produced in the liver?
Fibrinogen, Factor 2 (prothrombin), 7, 9 and 10.
ANd protein C, S and antithrombin which aid fibrinolysis
What causes pre-hepatic jaundice?
Excessive RBC breakdown which overwhelms the livers ability to conjugate bilirubin => Unconjegated hyperbilirubinaemia.
Haemolytic anaemia, Gilbert’s syndrome
What causes hepatocellular jaundice?
Liver dysfunction.
Liver loses ability to conjugate bilirubin. Cirrhosis can compress the intrahepatic portions of the biliary tree causing obstruction => Mixed (conjugated and unconjugated bilirubin in the blood.
Alcoholic liver disease, Viral hepatitis, Medication, autoimmune hepatitis, HCC, Primary sclerosing cholangitis
What causes post hepatic jaundice?
Obstruction of biliary drainage. Bilirubin is conjugated in the liver but cannot get into gut and spills into blood => conjugated hyperbilirubinaemia. Gall stones (intraluminal) Wall causes (cholangiocarcinoma, strictures) Outside of the wall compression (pancreatic cancer or abdo mass)
What colour is conjugated bilirubin (soluble) in the urine?
Brown- so an excess of conjugated billirubin (post hepatic or hepatocellular) makes the urine very dark brown (coca cola)
What is albumin?
A marker of liver synthesising function
What is the half life of ALP?
A week. May lag behind disease and continue after treatment.
What is the classic faeces/rine picture for cholestatic disease?
Pale faeces and dark urine.
How is bilirubin transported in the blood?
Bound to albumin
Which clotting factors does the liver synthesise?
Fibrinogen (factor 1)
Prothrombin (factor 2)
Factor 5, 7, 9, 10, 12 and 13.
What does PT time measure?
Time it takes for prothrombin to be converted to thrombin.
What does an elevated PT suggest?
Reduced synthetic function of the liver. Not necessarily pro haemorrage as the liver also synthesis protein C, S and antithrombin and these will also be reduced in poor liver function.
What causes, excluding liver function can prolong the prothrombin time?
Drugs (warfrin)
Bile malabsorbtion causing relative Vit K deficiency
Consumptive (sepsis)/congenital (Haemophillia) coaguopathies
The reference ranges for LFTs change around the country. Can people have liver disease and normal LFTs?
Yes- all in the history and presentation
What drugs can cause a change in LFTs?
Antibiotics, antidepressants, Statins, NSAIDs (naproxen and diclofenac), anti-epileptics, anti-TB drugs, OTC drugs
What is the half life of albumin?
10 days
WHat is the ALT half life?
47 hours
What is the AST half life?
17 hours
Which is more liver specific AST or ALT?
ALT
What is the LFT picture for Acute hepatocyte injury?
AST:ALT ratio >2 is suggestive of alcohol cause (normal is 0.8)
What are the mimic/overlap conditions of acute hepatic injury?
Coeliac disease (Use tTG to exclude) Muscle disorders (Use Creatinine to exclude) Adrenal deficiency Anorexia
What is the test for Autoimmune hepatitis?
Anti smooth muscle antibodies serology
What is the test for Wilsons disease?
Caeruplasmin- Low because the copper accumulates in tissues rather than serum
What is the test for haemochromatosis?
Ferratin (acute phase protein) raised above 500
What are the causes of isolated hyperbilirubinaemia that is unconjugated?
Haemolytic anaemia.
Impaired hepatic bilirubin uptake (heart faiule or portosystemic shunts (TIPSS), Drugs (rifampicin)
What is the genetic disease whichleads to impaired bilirubin conjugation?
Gilbert’s syndrome.
Can also occur in hyperthyroidism and advanced liver disease
What can lead to hyperbilirubinaemia that is conjugated?
Extrahepatic: Cholelithiasis, PSC, Cholingiocarcinoma, Head of Pancreas mass, acute/chronic pancreatitis.
Intrahepatic: Sepsis/hypoperfusion, cirrosis, TPN, acute hepatitis, Drgs (steroid, ripampicin, chlorpromazine.
What are the signs of acute liver failure? IMPORTANT
Jaundice, coagulopathy and encephalopathy
What is a Fibroscan?
test used to measure the elasticity of the liver- tries to aviod biopsies.
What are the signs of congestive hepatitis?
Dilated IVC and hepatic vein with right heart failure.
What causes splenomegaly in young people?
EBV or CMV- no contact sports
When do you worry about herpes simplex virus?
Pregnant or immunocomprimised.
Not everyone has a rash and it is foetotoxic
