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Toronto Notes 2019 Liver Gastroenterology G35 Non-Alcoholic Fatty Liver Disease
Definition
• spectrumofdisorderscharacterizedbymacrovesicularhepaticsteatosis,sometimeswithinflammation and/or fibrosis
• mostcommoncauseofliverdiseaseinNorthAmerica
Etiology
• pathogenesisnotwellelucidated;insulinresistanceimplicatedaskeymechanism,leadingtohepatic steatosis
• histologicalchangesindistinguishablefromthoseofalcoholichepatitisdespitenegligiblehistoryof alcohol consumption
Risk Factors
• likelyacomponentofthemetabolicsyndromealongwithT2DM,HTN,hypertriglyceridemia • rapidweightlossorweightgain
Clinical Features
• oftenasymptomatic
• maypresentwithfatigue,malaise,andvagueRUQdiscomfort
• elevatedserumtriglyceride/cholesterollevelsandinsulinresistance
Investigations
• elevatedserumAST,ALT±ALP;AST/ALT<1
• presentsasechogeniclivertextureonultrasound
• non-invasive testing of fibrosis: FIB4, NAFLD fibrosis score, Fibrotest, Fibroscan
• liverbiopsycannotdistinguishfattyliverfromalcoholvsnon-alcoholicfattyliver,butconsideredwhen
investigating alternative etiologies or assessing for level of fibrosis
Treatment
• mainstayisgradualweightloss(0.5-1kg/wk)asrapidweightlosscanworsenliverdisease ■ ideally, aim to lose at least 7-10% of body weight
• someevidenceforvitaminE(800Udaily)ifthereishepaticinflammation • someevidenceforbenefitsofcoffeedrinking(3cups/d)andvitaminD
Prognosis
• mostdiefromcardiovascularorcerebrovasculardisease
• betterprognosisthanalcoholichepatitis
■ <25% progress to cirrhosis over a 7-10 yr period
• riskofprogressionincreasesifinflammationorscarringoccursalongsidefatinfiltration(non-alcoholic
steatohepatitis)
• otherclinicalindicatorsofunfavourableprognosis:DM,age,metabolicsyndrome,higherlevelsof
fibrosis
Acute Liver Failure (formerly Fulminant Hepatic Failure)
Definition
• severedeclineinliverfunctioncharacterizedbycoagulationabnormality(INR>1.5)and encephalopathy
• insettingofpreviouslynormalliver
• rapid(<26wkduration)
Etiology
• drugs(especiallyacetaminophen),hepatitisB(measureanti-HBc,IgMfractionbecausesometimes HBV-DNA and even HBsAg rapidly becomes negative), hepatitis A, hepatitis C (rare), ischemic, idiopathic
Treatment
• correcthypoglycemia,monitorlevelofconsciousness,preventGIbleedingwithPPI,monitorfor infection and multiorgan failure (usually requires ICU)
• considerliverbiopsybeforeINRbecomestoohigh
• chiefvalueofbiopsyistoexcludechronicdisease,lesshelpfulforprognosis
• livertransplant(King’sCollegecriteriacanbeusedasprognosticindicator):considerearly,especiallyif
time from jaundice to encephalopathy >7 d (e.g. not extremely rapid), age <10 or >40, cause is drug or unknown, bilirubin >300 μmol/L, INR >3.5, creatinine >200 μmol/L