Nonalcoholic steatohepatitis: an evolving diagnosis.

Area of Science:

• Hepatology
• Gastroenterology
• Internal Medicine

Background:

• Nonalcoholic steatohepatitis (NASH) is a histological diagnosis characterized by liver fat accumulation, inflammation, and hepatocyte injury in the absence of alcohol use.
• Obesity is a primary risk factor for NASH, with emerging evidence suggesting hyperinsulinism's role in its pathophysiology.
• Patients may present with nonspecific symptoms like fatigue and right upper quadrant pain, and elevated aminotransferases, though these can also be normal.

Purpose of the Study:

• To define Nonalcoholic steatohepatitis (NASH) and its diagnostic criteria.
• To outline the risk factors, clinical presentation, and diagnostic workup for NASH.
• To discuss the prognostic implications and treatment strategies for NASH.

Main Methods:

• Histological examination of liver biopsy is the gold standard for NASH diagnosis.
• Exclusion of other liver disease causes, including viral and metabolic etiologies.
• Assessment of liver enzyme levels (ALT typically > AST in NASH) and imaging studies (ultrasound, CT, MRI) for hepatic steatosis.

Main Results:

• Liver biopsy reveals steatosis, inflammation, hepatocyte injury, and fibrosis in NASH.
• Elevated aminotransferases, particularly ALT > AST, can suggest NASH and help exclude alcohol abuse.
• Imaging can detect significant hepatic steatosis but cannot differentiate benign steatosis from NASH.

Conclusions:

• A liver biopsy is essential for diagnosing NASH, assessing fibrosis for prognosis, and ruling out other liver conditions.
• Weight loss is the cornerstone of treatment for obese patients with NASH.
• While the progression to cirrhosis is uncertain, NASH accounts for approximately 1% of liver transplants.