Lhépatose

Hepatic steatosis, also called l'hépatose in French, is the accumulation of fat in liver cells. It is defined histologically when fat droplets constitute more than 5% of hepatocytes, and can be diffuse or focal.

Etiology: Most cases are related to metabolic risk factors such as obesity, insulin resistance, type 2 diabetes, and dyslipidemia (non-alcoholic fatty liver disease, NAFLD). Alcoholic fatty liver disease (AFLD) results from excessive alcohol intake. Other causes include rapid weight loss, certain medications, viral hepatitis, and pregnancy.

Clinical features: Many patients are asymptomatic. When present, fatigue or mild right upper quadrant discomfort may occur. Hepatomegaly may be found on examination. Steatosis can progress to non-alcoholic steatohepatitis (NASH) with inflammation and fibrosis, and in advanced cases to cirrhosis and hepatocellular carcinoma.

Diagnosis: Evaluation combines history, laboratory tests, imaging, and sometimes biopsy. Liver enzymes may be normal or show a mild-to-moderate elevation of ALT and/or AST, often with an AST:ALT ratio less than 1 in NAFLD. Ultrasound is commonly used and shows increased liver echogenicity. MRI or CT can quantify fat; elastography assesses fibrosis. Liver biopsy is the reference standard to distinguish simple steatosis from NASH and to stage fibrosis.

Management: The mainstay is addressing metabolic risk factors: weight loss through diet and exercise, management of diabetes and lipids, and avoidance of alcohol. Pharmacologic treatment is not universally approved; vitamin E and pioglitazone may be considered in select patients with NASH after risk assessment. Regular follow-up to monitor progression is advised.

Prognosis and epidemiology: NAFLD is a common cause of chronic liver disease worldwide, with progression risk linked to the development of inflammation and fibrosis. The prognosis depends on presence and degree of fibrosis and associated comorbidities.