From the Guidelines
NAFLD (Non-Alcoholic Fatty Liver Disease) and NASH (Non-Alcoholic Steatohepatitis) are two related but distinct liver conditions, with the main difference being the presence of inflammation and liver cell damage in NASH, which is not seen in NAFLD 1.
Key Differences
- NAFLD is characterized by the accumulation of excess fat in liver cells, but without significant inflammation or liver cell damage 1.
- NASH, on the other hand, is a more aggressive form of liver disease, characterized by inflammation and liver cell damage, in addition to excess fat accumulation, which can lead to scarring and fibrosis of the liver 1.
Diagnosis and Treatment
- A definitive diagnosis of NAFLD or NASH can only be made by a liver biopsy 1.
- Treatment should be tailored to each individual's specific needs and medical history, with lifestyle modifications such as weight loss, exercise, and a healthy diet being recommended 1.
- In some cases, medications such as vitamin E or pioglitazone may be prescribed to help reduce liver inflammation and improve insulin sensitivity, but their use should be individualized and monitored by a healthcare provider 1.
Complications and Risks
- NASH is a leading cause of hepatocellular carcinoma (HCC) and liver transplantation in the U.S. 1.
- Patients with NAFLD are at increased risk for cardiovascular disease and extrahepatic cancer 1.
- The risk of progression to cirrhosis and liver failure is higher in NASH than in NAFLD 1.
From the Research
Definition and Difference
- Non-Alcoholic Fatty Liver Disease (NAFLD) is a spectrum of liver abnormalities, including isolated steatosis, non-alcoholic steatohepatitis (NASH), advanced fibrosis, and cirrhosis 2.
- NAFLD encompasses a disease continuum from steatosis with or without mild inflammation (non-alcoholic fatty liver), to NASH, which is characterized by necroinflammation and faster fibrosis progression than non-alcoholic fatty liver 3.
- The key difference between NAFLD and NASH is the presence of inflammation and hepatocyte injury in NASH, which can progress to cirrhosis and hepatocellular carcinoma 4, 5.
Clinical Characteristics
- NAFLD is often asymptomatic, but can be suspected due to abnormal aminotransferases or a bright liver on abdominal ultrasound 5.
- NASH is characterized by fatty change with inflammation and evidence of hepatocyte injury, such as ballooning degeneration, and presence of fibrosis is a sign of chronicity 4.
- Age >45 years, obesity, and diabetes have been associated with an increased risk of liver fibrosis and progression to cirrhosis in NAFLD patients 5.
Diagnosis and Classification
- The diagnosis of NAFLD is based on a history of no or limited daily alcohol intake, presence of hepatic steatosis by imaging or histology, and exclusion of other liver diseases 4.
- NAFLD could be both the result and the cause of metabolic syndrome, with a vicious cycle operating between these conditions 4.
- The diagnosis of NASH requires a liver biopsy, which is the gold standard for diagnosis, but non-invasive modalities such as predictive models, serum biomarkers, and radiological techniques are being developed 2, 6.