Non-alcoholic Fatty Liver Disease (NAFLD) is related to fat deposition in liver, which is related to elevated BMI
NAFLD also linked to metabolic syndrome (elevated TGs, central adiposity, low HDL, high BP, elevated sugar)
Estimated ~25% of US adults have NAFLD
~25% of patients w/NAFLD will progress to Non-Alcoholic Steatohepatitis (NASH), where there is hepatocyte destruction and fibrosis
~25% of those w/NASH will develop cirrhosis, ~30% of whom will develop decompensated dz at 8y, and a small % will develop HCC (over years)
Risk of progression related to degree of deposition, duration, host factors, other concurrent exposures (e.g. Hep C, ETOH, etc)
Risk Factors
For NAFLD: obesity, diabetes, hypertension, hyperlipidemia, PCOS, OSA, age, genetics, other
Symptoms
NAFLD is typically asymptomatic; NASH also asymptomatic until/unless findings of cirrhosis w/portal htn and/or HCC
With NAFLD, major cause of morbidity/mortality is cardiovascular disease, so might have symptoms from that
Liver related symptoms (and disease) can develop more quickly if coexistent liver insult (e.g. ETOH)
Over years, if cirrhosis develops, may develop typical findings of portal htn and advanced liver dz: ascites, jaundice, fatigue, confusion, bleeding, etc.
Physical Exam Findings
Elevated BMI
In asymptomatic phase, may have painless hepatomegaly
If cirrhosis develops, can have typical findings of: jaundice, ascites, edema, spiders, gynecomastia, icterus, splenomegaly, etc.
Tests
For NAFLD, transaminases can be normal; if elevated, ALT typically > AST, with values typically < 5x ULN; INR, albumin, bilirubin, CBC typically normal
Rule out other contributors (e.g. ETOH, Hep C, Hep B, Wilsons dz, Hemochromatosis, alpha-1 anti-trypsin, DILI, autoimmune hep)
Ultrasound or CT often demonstrate fatty infiltration in NAFLD and NASH
Identifying NASH can be done by assessing for fibrosis-induced stiffness via ultrasound elastography or MRI; Biopsy pursued if diagnosis unclear (and results will impact clinical approach)