Nonalcoholic Steatohepatitis (NASH)

What is Nonalcoholic Steatohepatitis (NASH)? Nonalcoholic steatohepatitis (NASH) is a subtype of nonalcoholic fatty liver disease (NAFLD) characterized by progressive disease with triglyceride accumulation, injury to the hepatocytes, and inflammation. It affects approximately 3-6% of the US population, with an increasing prevalence attributed to the increased incidence of the associated risk factors.

What causes NASH?

NASH results from fat deposition within the hepatocytes, likely from increased production or inability to clear the triglycerides. The steatosis causes damage to hepatocytes, resulting in inflammation and subsequent fibrosis. The exact mechanism of the disease is not entirely elucidated but is thought to be influenced by the interplay of genetics, environmental, and metabolic factors. Possible factors implicated in the pathophysiology include:

  • Gut microbiome
  • Oxidative stress
  • Insulin resistance
  • Bile acid metabolism
  • Lipotoxicity

Signs and Symptoms of NASH

Most patients with NASH and NAFLD are asymptomatic or may present with nonspecific symptoms of fatigue or abdominal discomfort. Patients with more severe complaints often have progressed to complications, such as cirrhosis and hepatocellular carcinoma.

Source: Sheka, A. C., Adeyi, O., Thompson, J., Hameed, B., Crawford, P. A., & Ikramuddin, S. (2020). Nonalcoholic Steatohepatitis. JAMA, 323(12), 1175.