Nonalcoholic Steatohepatitis (NASH)
Overview
What is nonalcoholic steatohepatitis (NASH)?
Nonalcoholic steatohepatitis (NASH) is liver inflammation caused by a buildup of fat in the liver. NASH is part of a group of liver diseases, known as nonalcoholic fatty liver disease, in which fat builds up in the liver and sometimes causes liver damage that gets worse over time (progressive liver damage).
Although the cause is not known, NASH seems to be related to certain other conditions, including obesity, high cholesterol and triglycerides, and diabetes. Treatment for NASH involves controlling those underlying diseases.
What causes NASH?
The exact cause of NASH is not known. It most commonly affects people who are middle-aged and are overweight or obese, have high cholesterol and triglycerides, or have diabetes. Yet it can occur in people who have none of these risk factors. Excess body fat along with high cholesterol and high blood pressure are also signs of a condition called metabolic syndrome. This condition is closely linked to insulin resistance.
Along with excess fat in the liver, which many people have, several other factors may contribute to the liver damage. These are:
- Resistance to insulin, which means that the body can't use sugar (glucose) in the way it should. Normally, your body makes insulin after you eat a meal that has sugar in it. Insulin helps the extra sugar in your blood get into your muscles and liver. If your body does not respond to insulin in this way, then the sugar level in your blood will stay high. This is how insulin resistance can increase your chance of developing type 2 diabetes.
- Changes in how the liver makes fat and what the liver does with fat that is delivered to it by the intestines.
Other factors that have been known to contribute to NASH include:
- Having had surgeries that shorten the intestines, the stomach, or both, such as jejunal bypass operation or biliopancreatic diversion.
- Using a feeding tube or other method of receiving nutrition for a long time.
- Using certain medicines, including amiodarone, glucocorticoids, synthetic estrogens, and tamoxifen.
What are the symptoms?
NASH is a condition that may get worse over time (called a progressive condition). For this reason, you may have no symptoms until the disease progresses to the point that it begins to affect the way the liver works (liver function). As liver damage gets worse, symptoms such as tiredness, weight loss, and weakness may develop.
It may take many years for NASH to become severe enough to cause symptoms. In some cases, the progress of the condition can stop and even reverse on its own without treatment. But in other cases NASH can slowly get worse and cause scarring (fibrosis) of the liver, which leads to cirrhosis. Cirrhosis means that liver cells have been replaced by scar tissue. As more of the liver becomes scar tissue, the liver hardens and can't work normally.
Who is affected by NASH?
NASH affects about 2% to 5% of people in the United States.1 Middle-aged people who are obese are most commonly affected by NASH.
How is NASH diagnosed?
To diagnose liver disease, your doctor will ask about your medical history, and you will have a physical exam along with some tests to identify possible causes of liver disease. Imaging tests may include an ultrasound, a CT scan, or an MRI scan. A liver biopsy may be recommended to confirm the diagnosis and to see if your liver has been damaged. In a biopsy, a sample of tissue is collected from the liver and examined under a microscope for abnormal signs.
How is it treated?
Although there is no specific treatment for NASH, you can manage the underlying conditions that contribute to the liver damage. This may include reducing your total cholesterol level, losing weight, controlling diabetes, and stopping the use of any medicine that may be causing the symptoms or making them worse. You will also need to avoid drinking excessive amounts of alcohol, because this can make fatty liver disease worse.
Frequently Asked Questions
Learning about nonalcoholic steatohepatitis (NASH):
Being diagnosed:
Getting treatment:
Ongoing concerns:
Living with NASH:
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| Author: | Monica Rhodes | Last Updated: July 18, 2007 |
| Medical Review: | Kathleen Romito, MD - Family Medicine W. Thomas London, MD - Hepatology | |
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