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Stages of NASH

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By Editorial Team

3 min read

Reviewed by: HU Medical Review Board | Last reviewed: May 2024

Nonalcoholic steatohepatitis (NASH) is a liver disease that should be taken seriously. NASH is an advanced stage of nonalcoholic fatty liver disease (NAFLD). NAFLD is the most common liver disease in the world.1,2

Often referred to as a “silent disease,” NASH quietly progresses through different stages. It impacts liver health without noticeable symptoms until it reaches advanced stages. Understanding the stages of both NAFLD and NASH is crucial for early detection and management of the condition.1

Stage 1: Steatosis

During the beginning stages of NAFLD, fat builds up in the liver. This is called steatosis. While some fat in the liver is normal, an excessive amount can lead to inflammation and damage to the liver over time.2

In stage 1, people do not experience any noticeable symptoms. But liver function tests may detect abnormal levels of liver enzymes. Typically, steatosis can be detected if there is 20 to 30 percent of fat in the liver. But even 5 to 10 percent of fat in the liver is considered abnormal.2-4

At this stage, it is possible to reduce your risk of NAFLD and NASH. You can do this by:3

  • Losing excess body weight
  • Eating a healthy diet
  • Exercising regularly
  • Managing other health conditions that are risk factors for liver disease (type 2 diabetes, obesity, and cardiovascular disease)

Stage 2: Nonalcoholic steatohepatitis (NASH)

As fat continues to accumulate, inflammation of the liver gets worse. Stage 2 involves fat buildup, inflammation, and liver cell damage.2

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Symptoms may start to appear at this stage, such as:1,3

  • Fatigue
  • Generally not feeling well (malaise)
  • Pain or discomfort in the upper right stomach area (where the liver is located)

Stage 3: Advanced fibrosis

Stage 3 occurs when chronic inflammation in the liver leads to scarring. Scarring in the liver is known as fibrosis. As scar tissue grows, it can disrupt liver function and impair blood flow through the organ. Fibrosis occurs slowly over time, gradually worsening liver health if left untreated. However, at this stage, the damage is still reversible if the causes of NAFLD are addressed.2,3

With stage 3, people may have more noticeable symptoms, though many do not. These symptoms can include:1,3

  • Pain in the upper right stomach area
  • Shortness of breath
  • Swelling in the stomach or legs
  • Bruising or bleeding easily

Stage 4: Cirrhosis

The most advanced stage of NASH is cirrhosis. This is when extensive scarring and damage have occurred in the liver. At this level, the damage to the liver cannot be reversed.2,4

Cirrhosis can lead to severe complications such as end-stage liver disease, liver failure, and liver cancer. With cirrhosis, death rates sharply increase. At this stage, a liver transplant may be needed.2,4

At stage 4, symptoms can include:1,3

  • Itchy skin
  • Abdominal pain and swelling
  • Red palms
  • Yellowing of the skin and eyes (jaundice)
  • Spider-like blood vessels on the skin
  • Confusion or drowsiness
  • Bruising or bleeding easily
  • Swelling of the legs

How stages of NASH are diagnosed

The first step in getting diagnosed is to see your primary care doctor. From there, they may refer you to a hepatologist, a doctor who specializes in the liver. A NASH diagnosis may involve:4,5

  • A physical exam and medical history
  • Liver function tests – These are blood tests that measure how well your liver is functioning.
  • Imaging tests – Examples include ultrasound, computed tomography (CT) scan, elastography, and magnetic resonance imaging (MRI).
  • Liver biopsy – In this procedure, a sample of the liver is taken and studied by a pathologist.

Other tools can help determine how severe liver damage is. One such tool is called the fibrosis-4 (Fib-4) calculator. This is a noninvasive tool used to help evaluate the severity of liver fibrosis and guide treatment decisions. It calculates the likelihood of advanced fibrosis or cirrhosis based on:2,6

  • Age
  • Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels – These are enzymes found in the body that help with metabolic processes. High levels of these enzymes can indicate potential liver problems.
  • Blood platelet count – When scarring happens, platelets can get trapped and are not circulated as they should be. Decreased platelets in the blood can be a sign of more advanced fibrosis.

A low Fib-4 score suggests a lower risk of advanced fibrosis. A high score may indicate the need for further evaluation and monitoring.2,6

Get your liver checked by a doctor

If you have any symptoms or risk factors for NAFLD or NASH, see your doctor. They can help assess your liver function and work toward a diagnosis. Understanding the stages of NASH can help you catch NASH early and get the right treatment.4,5