Liver damage signs and interpretation of LFTs Flashcards
What are the signs of liver disease?
Jaundice Hepatomegaly Spider naevi Palmar erythema Gynaecomastia Bruising - due to abnormal clotting Ascites Caput Medusae Asterixis
Splenomegaly occurs in cirrhosis due to portal hypertension
What is a useful marker for hepatocellular injury?
ALT - as it is found in high concentration within hepatocytes and enters the blood following hepatocellular injury
What is a useful marker for cholestasis?
ALP - it is particularly concentrated in the liver, bile duct and bone tissue and is often raised in response to cholestasis
How do we compare the rise in ALT and ALP?
> x10 increase in ALT and x3 increase in ALP = cholestasis
Can have a mixed picture involving both hepatocellular injury and cholestasis
What liver marker needs to be checked if ALP is raised?
If there is a rise in ALP, important to check GGT levels:
Raised GGT = biliary epithelial damage, bile flow obstruction, alcohol, or drugs e.g. phenytoin
Raised ALP with raised GGT = cholestasis
What is a raised ALP in the absence of raised GGT indicative of?
Suggests non-hepatobiliary pathology: Bony metastases or primary bone tumour (e.g. sarcoma) Vitamin D deficiency Recent bone fracture Renal osteodystrophy
What is the cause of jaundice without raised ALT and ALP?
Isolated rise in bilirubin:
Gilbert’s syndrome (most common)
Haemolysis - check blood film, FBC, reticulocyte count, haptoglobin and LDH levels to confirm
What investigations can be used to assess synthetic liver function?
Serum bilirubin
Serum albumin
Prothrombin time (PT)
Serum blood glucose
How can the colour of the urine and stools be used to identify the cause of jaundice?
Normal urine + normal stools = pre-hepatic cause
Dark urine + normal stools = hepatic cause
Dark urine + pale stools = post-hepatic cause (obstruction)
What the causes of unconjugated and conjugated hyperbilirubinaemia?
Unconjugated:
Haemolysis (e.g. haemolytic anaemia)
Impaired hepatic uptake (e.g drugs, CCF)
Impaired conjugation (e.g Gilber’s syndrome)
Conjugated:
Hepatocellular injury
Cholestasis
What can cause albumin levels to fall?
Liver disease (e.g. cirrhosis) causing reduced production of albumin
Inflammation triggering acute phase response which temporarily decreases liver’s production of albumin
Excessive loss of albumin due to protein-losing enteropathies or nephrotic syndrome
What can happen to prothrombin time in liver disease?
PT can increase and lead to thinner blood and bruising
How can AST/ALT ratio be used to determine the likely cause of LFT derangement?
ALT>AST is associated chronic liver disease
AST>ALT is associated with cirrhosis and acute alcoholic hepatitis
AST:ALT ratio normally >2. A ratio >3 is strongly suggestive of acute alcoholic hepatitis
