non alcoholic fatty liver disease Flashcards
what is non alcoholic fatty liver disease?
fatty infiltration of liver in absence of secondary cause - >5% steatotic hepatocytes
what is NASH?
non alcoholic steatohepatitis. NAFLD plus inflammation.
what is the disease progression of NAFLD?
NAFLD: hepatic steatosis (fatty infiltration of liver)
becomes NASH -with hepatocyte injury and inflammation. this step is reversible
becomes advanced fibrosis. this step is reversible
becomes cirrhosis
what factors increase risk of progression to next stage of NAFLD?
T2DM and poor diabetic control
weight gain
metabolic syndrome
inactivity
diet -high sat/trans fat, sugar, and fructose intake
inactivity
increasing age but probably secondary cause
genetics -PNPLA3, TMFF6
OSA
what factors increase the chance of regression to previous stage of NAFLD?
weight loss
exercise (independent of weight loss)
med diet
good diabetic control
coffee consumption
pathophysiology of NAFLD in patient friendly wording?
excess fat in the body means that more fat is going into the liver. it also means that the liver is making more fat and it’s harder for the liver to get rid of fat once it’s made it.
if smart patient/asking about diabetes: insulin resistance leads to inappropriate breakdown of fat which causes more fat going into the liver and more inflammation in the liver
how do you diagnose NAFLD?
one of:
- raised ALT and/or GGT and evidence of steatosis on imaging
- imaging evidence of steatosis
- raised ALT and/or GGT and evidence of insulin resistance /central obesity/metabolic risk factors even if imaging is negative
PLUS all of:
- no history of excess alcohol
- no know pre-existing liver disease
- no hepatotoxic drugs
- negative blood screen for other liver diseases.
liver biopsy may be needed if diagnostic uncertainty -pragmatic diagnosis
what is the cutoff alcohol intake for it to be non alcoholic liver disease instead of alcoholic?
less than 2.5 units a day for females
less than 3.75 for men
what are some signs of advanced liver disease on examination?
jaundice, spider naevi, palmar erythema, ascites, hepatomegaly, splenomegaly, hepatic encephelopathy
what is the most common LFT abnormality in NAFLD?
raised GGT
what is the significance of ALT and AST in NAFLD and what do you have to think about while interpreting it?
ALT is in normal range in up to 80% of NAFLD patients.
ALT typically falls with advanced fibrosis and increasing age
AST to ALT ratio increases as fibrosis advances
which LFTs suggest advanced fibrosis?
high AST:ALT ratio
low albumin
raised billirubin
which antibody is raised in half of NAFLD patients?
IgA
what is the significance of testing for ferritin and transferrin and what would you see in NAFLD?
screening for HH -high both
1/3 of patients with NAFLD have high ferritin and normal transferrin
how good is USS at detecting NAFLD?
good test for 1st line
if there is less than 30% steatosis might miss it -needs further investigation if high risk even if negative
