Stages of Fatty Liver Disease

Fatty liver tends to progress through stages, though many people stay at the first stage for life.

Stage 1: Simple fatty liver (steatosis)

Fat builds up in liver cells with little or no inflammation. There are usually no symptoms. This stage is often reversible.

Stage 2: Steatohepatitis (MASH or NASH)

Inflammation and liver cell injury appear along with the fat. Liver blood tests may be raised. Some people notice tiredness or upper abdominal discomfort.

Stage 3: Fibrosis

Scar tissue starts to form. It is graded from F1 (mild) to F3 (advanced). Early fibrosis can improve if the cause is controlled.

Stage 4: Cirrhosis

The liver becomes hard and scarred and may not work well. Complications such as fluid in the abdomen, bleeding from swollen veins, jaundice and confusion can develop. Damage is largely not reversible, though further harm can be slowed.

Liver cancer risk

People with cirrhosis, and occasionally those with earlier stages, have a higher risk of liver cancer and need regular monitoring.

How stage is assessed

• Liver blood tests
• Ultrasound
• FibroScan (liver stiffness test)
• Blood-based fibrosis scores such as FIB-4
• Sometimes a liver biopsy