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Nonalcoholic fatty liver disease vs. nonalcoholic steatohepatitis: A guide

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NAFLDNASHDiagnosisDifferencesSummary
Nonalcoholic fatty liver disease (NAFLD) happens when fat builds up in the liver. Nonalcoholic steatohepatitis (NASH) is a serious stage of NAFLD that can cause liver cancer, scarring, and other complications.
Medically reviewed by Alexandra Perez, PharmD, MBA, BCGP
Updated on

NAFLD is a term that refers to a condition that occurs when too much fat accumulates in your liver. NAFLD and excessive alcohol consumption aren’t related, but NAFLD is more common in people with obesity or overweight.

NASH is a serious stage of NAFLD that can cause inflammation in addition to the buildup of fat in your liver. The inflammation may permanently damage your liver and increase the risk of liver cancer and liver failure.

NAFLD

An adult with NAFLD or NASH walking outside in workout gear
Igor Alecsander/Getty Images

NAFLD is one of the most common causes of liver disease in the United States. Specialists estimate approximately 24% of adults in the United States have NAFLD.

Different from alcohol-associated liver disease, NAFLD isn’t linked to excessive alcohol consumption.

There are two types of NAFLD: the more serious nonalcoholic steatohepatitis (NASH) and nonalcoholic fatty liver (NAFL). You may develop either one or another. But sometimes, there may be a switch from one condition to another due to several factors.

Doctors do not know what exactly causes NAFLD, but they believe it may develop due to a combination of genetics, dietary choices, and certain health conditions. You may develop NAFLD without having any risk factors, but certain factors can increase your risk of having this condition, such as:

  • overweight or obesity
  • metabolic syndrome
  • high cholesterol
  • high blood pressure (hypertension)
  • low levels of physical activity
  • eating foods that are processed and high in sugar
  • type 2 diabetes
  • having a health condition related to insulin resistance, such as polycystic ovary syndrome

People with NAFLD do not usually develop any noticeable symptoms, but some of the NAFLD symptoms may include:

  • yellowing of the eyes and skin (jaundice)
  • fatigue
  • weakness
  • abdominal pain in the upper right side
  • weight loss
  • swelling of the legs
  • swelling in the abdomen due to fluid buildup (ascites)

In its early stages, NAFLD does not typically cause any harm. However, if left unmanaged, the illness can progress and cause serious complications.

There is no specific treatment for NAFLD. Doctors usually recommend several lifestyle changes, such as:

  • maintaining a moderate body weight
  • eating a balanced diet rich in fruits and vegetables
  • limiting the intake of added sugars and saturated fats
  • avoiding alcohol (if you drink)
  • engaging in some form of physical activity
  • managing blood sugar and cholesterol levels

If you have hypertension, a doctor might recommend some medications to manage it and prevent or slow the development of NAFLD. Examples include:

Doctors prescribe medications like ezetimibe (Zetia) and pravastatin (Pravachol) to help manage high cholesterol.

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NASH

NASH is a serious form of NAFLD that affects about 1.5–6.5% of people in the United States.

NASH is a condition where fat builds up in the liver and also causes inflammation. This inflammation may lead to liver damage in the form of liver fibrosis (scarring). NASH can also cause permanent liver damage, known as cirrhosis. Liver cirrhosis can cause liver cancer.

The causes and risk factors of NASH are similar to those of NAFLD. If people with NAFLD gain more weight, they may have a higher risk of developing NASH. Other risk factors of NASH may include:

If you have NASH, you may not notice any symptoms, even in the case of cirrhosis. The symptoms of NASH may include:

  • ascites
  • jaundice
  • intense itching
  • increased bruising and bleeding
  • mood changes
  • slurred speech
  • confusion
  • the appearance of spider-like blood vessels (telangiectasia) under the skin’s surface

Similar to NAFLD, there is no specific treatment for NASH. Doctors typically recommend a combination of medications, dietary and lifestyle changes. They usually prescribe medications for treating other coexisting health conditions or prevent potential complications, such as diabetes, obesity, or insulin resistance.

If NASH causes liver cancer or liver failure, you may need to undergo a liver transplant to restore your health.

Diagnosis

As NAFLD may not cause any symptoms, doctors typically diagnose this condition after a standard blood test, and the result shows unusually high levels of liver enzymes.

The result can suggest several types of liver diseases. Doctors may recommend various tests to rule out other conditions before diagnosing NAFLD.

Specialists may conduct a physical exam to examine the signs of insulin resistance or cirrhosis. They may ask you to take certain imaging tests. Sometimes, they may collect a sample from your liver by using a needle inserted into your abdomen for additional laboratory testing.

The imaging tests for NAFLD and NASH may include:

  • CT scan
  • ultrasound
  • MRI
  • elastography to determine the stiffness of the liver and how advanced its fibrosis is

Differences

NAFLD may cause symptoms such as abdominal discomfort and liver enlargement and does not typically cause any liver damage or inflammation. But it can progress into NASH.

NASH, on the other hand, is more serious and can lead to inflammation and severe health complications, such as cirrhosis. NASH can lead to liver failure or cancer.

If you notice any signs or symptoms of NAFLD or NASH, you should speak with a doctor and book a consultation.

Summary

NAFLD is a condition that occurs when fat builds up in your liver. This condition does not typically show many symptoms or cause further complications. NASH is a more advanced stage of NAFLD. NASH is serious and can cause several health complications, including liver cancer and liver failure.

There is no specific treatment for NAFLD and NASH. Doctors typically recommend making dietary and lifestyle changes alongside medical treatment for managing coexisting conditions like hypertension or diabetes. If liver cancer or liver failure occurs, you may need to receive a liver transplant treatment.

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