All you have to know about NASH
Nonalcoholic steatohepatitis (NASH) is a condition that causes inflammation and accumulation of fat and fibrous tissue in the liver. Although a similar condition can occur in people who abuse alcohol, NASH occurs in those who drink little or no alcohol.
The exact cause of NASH is unknown. However, it is seen more frequently in people with certain medical conditions such as diabetes, obesity, and insulin resistance.
It is not clear how many people have NASH because it causes no symptoms. However, NASH is diagnosed in about 10 to 20 percent of people who have a liver biopsy. Most people are between the ages of 40 and 60 years, although the condition can also occur in children. NASH is seen more often in women than in men.
The cause of NASH is not clear, although research is ongoing in an attempt to find effective treatments. For now, treatment focuses on controlling some of the medical conditions associated with it (such as diabetes and obesity) and monitoring for progression.
Conditions associated with NASH
Although the cause of NASH is unknown, it is most frequently seen in people with one or more of the following conditions.
Obesity — More than 70 percent of people with NASH are obese – most between 10 and 40 percent heavier than their ideal body weight.
Diabetes — Up to 75 percent of people with NASH have type 2 diabetes.
Hyperlipidemia — About 20 to 80 percent of people with NASH have hyperlipidemia (high blood triglyceride levels and/or high blood cholesterol levels).
Insulin resistance — Insulin resistance refers to a state in which the body does not respond adequately to insulin. Insulin resistance often occurs in people with hyperlipidemia who are obese; this group of symptoms is known as the metabolic syndrome and is frequently seen in people with NASH.
Drugs and toxins — Several drugs used to treat medical conditions have been linked to NASH, including amiodarone, tamoxifen, steroids (eg. prednisolone, hydrocortisone), and synthetic estrogens.
Pesticides that are toxic to cells have also been linked to NASH.
Symptoms
Most people with NASH have no symptoms. Rarely, NASH is diagnosed in people with fatigue, a general feeling of being unwell, and vague discomfort in their upper right abdomen, although it is not clear if these symptoms are related to NASH.
Diagnosis
NASH is most often discovered during routine laboratory testing. Additional tests help confirm the presence of NASH and rule out other types of liver disease. Imaging tests (such as ultrasound, CT scan, or magnetic resonance imaging) may reveal fat accumulation in the liver but cannot differentiate NASH from other causes of liver disease that have a similar appearance. A liver biopsy may be required to confirm NASH.
Liver function tests — Blood tests to measure the liver function measure levels of substances produced or metabolized by the liver. These levels can help to diagnose NASH and differentiate NASH from alcoholic hepatitis. Levels of two liver enzymes (aspartate amino transferase [AST] and alanine amino transferase [ALT]) are elevated in about 90 percent of people with NASH.
Other blood tests — Additional blood tests are useful for ruling out other causes of liver disease. These usually include tests for viral hepatitis (hepatitis A, B, or C), and may include tests for less common cause of liver disease.
Liver biopsy — Although other tests may suggest a diagnosis of NASH, liver biopsy is required to confirm it, is helpful in determining the severity of NASH and may provide clues about the future course of the condition. The procedure involves collecting a small sample of liver tissue, which is sent to a laboratory for microscopic examination and biochemical testing.
Treatment
There is no cure for NASH. Treatment aims to control the conditions that are associated with NASH, such as obesity, diabetes, and hyperlipidemia. Several experimental treatments are being studied with drugs that treat insulin resistance.
Weight loss — Weight reduction can help to reduce levels of liver enzymes, insulin, and can improve quality of life. Weight loss should be gradual (no more than 3.5 lbs or 1.6 kg per week) since rapid weight loss has been associated with worsening of liver disease.
Treatment of insulin resistance and other medication — Several drugs are available for people with insulin resistance, and they are being studied in patients with NASH with variable benificial results; eg Thiazolidinediones, UDCA, Vit. E
Prognosis
NASH is typically a chronic condition (i.e, it persists for many years). It is difficult to predict the course of NASH in an individual. The good news is most people with NASH will not develop serious liver problems. Furthermore, liver function tests are stable over time in most people with NASH.
However, NASH can progress in some people. One study that tracked liver damage over time showed that the condition improved in about 3 percent of people, remained stable in 54 percent of people, and worsened in 43 percent of people. The most serious complication of NASH is cirrhosis, which occurs when the liver becomes severely scarred. Older diabetic women may be at increased risk.
(The writer is a Consultant Physician)
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