Bariatric Surgery: safe in well-compensated chronic liver disease + improves hepatic steatosis and necroinflammation (i.e., features of NAFLD/NASH); however, effects on hepatic fibrosis variable (might progress); pxs w/ NAFLD-related cirrhosis and portal HTN should be excluded; not contraindicated in otherwise eligible patients with NAFLD or NASH.

Liver Transplantation: NAFLD in whom end-stage liver disease develops; NAFLD may recur after transplantation. RFs for recurrent or de novo NAFLD after liver transplantation multifactorial: hyperTG, obesity, DM, and immunosuppressive therapies, partic glucocorticoids.

pxs deny hazardous levels of alcohol consumption (>1 drink/day in women or 2 drinks/day in men) (bc serum aminotransferase incr when exceeding these levels)

strongly a. w/ overweight/obesity + insulin resistance; can also occur in lean individuals (partic common in those w/ a paucity of adipose depots (i.e., lipodystrophy))

Ethnic/racial factors (prevalence low to high: African As, white As, Hispanic As)

most clinically benign extreme: simple accumulation of TG within hepatocytes (hepatic steatosis)

most clinically ominous extreme: cirrhosis + primary liver cancer

risk of developing cirrhosis extremely low in chronic hepatic steatosis, but incr as steatosis becomes complicated by histologically conspicuous hepatocyte death and inflammation (i.e., nonalcoholic steatohepatitis [NASH]: a heterogeneous condition: sometimes improves to steatosis or normal histology, sometimes remains relatively stable for years, sometimes results in progressive accumulation of fibrous scar that eventuates in cirrhosis)

Once NAFLD-related cirrhosis develops: annual incidence of primary liver cancer: 1%.

Abdominal imaging not able to determine which ppl w/ NAFLD have NASH, and specific blood tests to diagnose not available

Studies: serum ALT elevations that cannot be explained by etc + bc prevalence of such “cryptogenic” ALT elevations incr w/ BMI--> presumed that they are due to NASH-->NASH present in 25% of NAFLD--> cirrhosis develops in 6% of NAFLD

risk for advanced liver fibrosis highest in NASH who are >45–50 yrs of age + overweight/obese or w/ DM2

Both hepatocellular carcinoma + intrahepatic cholangiocarcinoma (ICC) reported to occur in NAFLD w/o cirrhosis--> NAFLD may be a premalignant condition.

NAFLD, NASH, and NAFLD-related cirrhosis not limited to adults; obesity + insulin resistance main RFs for pediatric NAFLD

hepatic steatosis: TG synth overwhelms disposal--> accumulation of fat within hepatocytes.

1. -->alter intestinal microbiota--> enhance energy harvest from dietary sources + intestinal permeability--> incr hepatic exposure to gut-derived products--> liver cells generate infl mediators--> inhibit insulin actions.

2. Obese adipose depots--> excessive soluble factors (adipokines)--> inhibit tissue insulin sensitivity

1 +2--> hyperglycemia--> hyperinsulinemia--> promotes lipid uptake, fat synth, and fat storage--> steatosis

TG precursors + metabolic by-products hepatotoxic--> hepatocyte lipotoxicity--> generation of other factors (e.g., infl cytokines, hormonal mediators)--> deregulate systems maintaining hepatocyte viability--> incr hepatocyte death--> release various factors that trigger wound healing responses that aim to replace (regenerate) lost hepatocytes: transient expansion of other cell types (ex myofibroblasts and progenitor cells) that make and degrade matrix, remodel vasculature, and generate replacement hepatocytes, as well as recruitment of immune cells that release factors that modulate liver injury and repair--> NASH (morphologic manifestation of lipotoxicity and resultant wound healing responses)

futile repair, i.e., progressive accumulation of wound healing cells, fibrous matrix, and abnormal vasculature (scarring)--> cirrhosis

current strategies focus on circumventing misrepair by preventing and/or reducing lipotoxic liver injury.

can be accomplished by HX + P/E, liver imaging (ultrasound ok, CT or MRI added expense), and blood tests to exclude other causes

liver may not be enlarged +tests may be completely normal--> confidence in Dx of NAFLD incr by identification of NAFLD RFs (incr BMI, insulin resistance/DM2, other parameters indicative of metabolic syndrome (ex hyperuricemia/gout, cardiovascular disease) in px / family members)

NASH w/ advanced fibrosis: most intensive scrutiny and intervention

blood testing: evidence of hepatic dysfunction (ex hyperbilirubinemia, hypoalbuminemia, prothrombin time prolongation) or portal HTN (ex thrombocytopenia)--> advanced NAFLD

P/E: stigmata of portal HTN (ex spider angiomata, palmar erythema, splenomegaly, ascites, clubbing, encephalopathy)--> advanced NAFLD

seldom complicated by serious adverse sequelae (ex significant bleeding, pain, or inadvertent puncture of other organs)--> relatively safe.

suffers from potential sampling error unless tissue cores of 2 cm or longer acquired

examination of tissue at a single point in time not reliable for determining whether processes are progressing or regressing but risk of serial liver biopsies within short time unacceptable

research to identify superior markers of liver injury: Serum levels of keratin 8 and 18 (epithelial cytoskeletal prs that undergo cleavage during apoptosis--> released into blood as hepatocytes die + appear to parallel severity of liver fibrosis)

Obesity present in 50–90% of subjects; Most also have other features of metabolic syndrome; Some have subtle stigmata of chronic liver disease (spider angiomata, palmer erythema, or splenomegaly); small minority w/ advanced NAFLD: complications of end-stage liver disease (jaundice, features of portal HTN) may be initial findings

A. w/ obesity, diabetes, hyperTG, HTN, and cardiovascular disease, (Other associations: chronic fatigue, mood alterations, obstructive sleep apnea, thyroid dysfunction, and chronic pain syndrome)

presence also independently a. w/ endothelial dysfunction, incr carotid intimal thickness, number of plaques in carotid and coronary arteries

(3) treatment of complications of advanced NAFLD: management of complications of cirrhosis + portal HTN, including primary liver cancers

Lifestyle changes + dietary modification: foundation for NAFLD treatment

loss of min 3–5% of body weight improving steatosis, but greater weight loss (up to 10%) necessary to improve steatohepatitis.

exercise that improve fitness may be sufficient to reduce hepatic steatosis (not others though)

pharmacologic therapies (orlistat, topiramate, and phentermine) to facilitate weight loss experimental.

Metformin: not currently recommended as a treatment for NASH.

thiazolidinediones (pioglitazone and rosiglitazone): Pioglitazone may be safer but caution when considering its use in impaired myocardial function.

Antioxidants: vitamin E should only be considered as a first-line pharmacotherapy for nondiabetic NASH; potentially negative effects on cardiovascular health

Ursodeoxycholic acid (a bile acid ) + betaine (metabolite of choline) : no benefit

Statins: do not cause liver failure in any chronic liver disease--> use of statins to treat dyslipidemia in NAFLD/NASH.

advanced NAFLD (cirrhosis and primary liver cancer) can occur in children + might follow a more aggressive course

certain environmental pollutants seem to exacerbate NAFLD.