hepatic steatosis
Summary
Hepatic steatosis is the accumulation of triglycerides within hepatocytes, producing a 'fatty liver' grossly enlarged, yellow, and greasy. It is most commonly caused by alcohol use, obesity/metabolic syndrome (NAFLD), and is reversible if the underlying insult is removed.
Detail
Mechanistically, alcohol metabolism by ADH/ALDH generates excess NADH, which favors fatty acid synthesis and inhibits beta-oxidation, leading to triglyceride accumulation. Histologically, hepatocytes show macrovesicular fat droplets that displace the nucleus to the periphery. NAFLD/NASH is associated with insulin resistance and may progress steatosis to steatohepatitis (with ballooning degeneration, Mallory-Denk bodies, neutrophilic infiltrate), fibrosis, and cirrhosis. Microvesicular steatosis (small droplets, central nucleus) is seen in Reye syndrome, acute fatty liver of pregnancy, and tetracycline/valproate toxicity. Boards classic: an obese diabetic with mildly elevated AST/ALT (ALT > AST in NAFLD; AST:ALT > 2 in alcoholic).
Sources
- First Aid for USMLE Step 1 2024
- Robbins Basic Pathology 10th ed
- Pathoma
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