NONALCOHOLIC FATTY LIVER DISEASE

NONALCOHOLIC FATTY LIVER DISEASE

Nonalcoholic fatty liver disease is an umbrella term for a range of liver conditions affecting people who drink little to no alcohol. As the name implies, the main characteristic of nonalcoholic fatty liver disease is too much fat stored in liver cells.

Nonalcoholic steatohepatitis, a potentially serious form of the disease, is marked by liver inflammation, which may progress to scarring and irreversible damage. This damage is similar to the damage caused by heavy alcohol use. At its most severe, nonalcoholic steatohepatitis can progress to cirrhosis and liver failure.

Nonalcoholic fatty liver disease is increasingly common around the world, especially in Western nations. In the United States, it is the most common form of chronic liver disease, affecting an estimated 80 to 100 million people.

Nonalcoholic fatty liver disease occurs in every age group but especially in people in their 40s and 50s who are at high risk of heart disease because of such risk factors as obesity and type 2 diabetes. The condition is also closely linked to metabolic syndrome, which is a cluster of abnormalities including increased abdominal fat, poor ability to use the hormone insulin, high blood pressure and high blood levels of triglycerides, a type of fat.

Symptoms

Nonalcoholic fatty liver disease usually causes no signs and symptoms. When it does, they may include:

• Enlarged liver

• Fatigue

• Pain in the upper right abdomen

Possible signs and symptoms of nonalcoholic steatohepatitis and cirrhosis (advanced scarring) include:

• Abdominal swelling (ascites)

• Enlarged blood vessels just beneath the skin's surface

• Enlarged breasts in men

• Enlarged spleen

• Red palms

• Yellowing of the skin and eyes (jaundice)

Causes

Experts don't know exactly why some people accumulate fat in the liver while others do not. Similarly, there is limited understanding of why some fatty livers develop inflammation that progresses to cirrhosis. Nonalcoholic fatty liver disease and nonalcoholic steatohepatitis are both linked to the following:

• Overweight or obesity

• Insulin resistance, in which your cells don't take up sugar in response to the hormone insulin

• High blood sugar (hyperglycemia), indicating prediabetes or actual type 2 diabetes

• High levels of fats, particularly triglycerides, in the blood

These combined health problems appear to promote the deposit of fat in the liver. For some people, this excess fat acts as a toxin to liver cells, causing liver inflammation and nonalcoholic steatohepatitis, which may lead to a buildup of scar tissue (fibrosis) in the liver.

Risk factors

A wide range of diseases and conditions can increase your risk of nonalcoholic fatty liver disease, including:

• High cholesterol

• High levels of triglycerides in the blood

• Metabolic syndrome

• Obesity, particularly when fat is concentrated in the abdomen

• Polycystic ovary syndrome

• Sleep apnea

• Type 2 diabetes

• Underactive thyroid (hypothyroidism)

• Underactive pituitary gland (hypopituitarism)

Nonalcoholic steatohepatitis is more likely in these groups:

• Older people

• People with diabetes

• People with body fat concentrated in the abdomen

It is difficult to distinguish nonalcoholic fatty liver disease from nonalcoholic steatohepatitis without further testing.

Complications

The main complication of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis is cirrhosis, which is late-stage scarring (fibrosis) in the liver. Cirrhosis occurs in response to liver injury, such as the inflammation in nonalcoholic steatohepatitis.  As the liver tries to halt inflammation, it produces areas of scarring (fibrosis). With continued inflammation, fibrosis spreads to take up more and more liver tissue.

If the process isn't interrupted, cirrhosis can lead to:

• Fluid buildup in the abdomen (ascites)

• Swelling of veins in your esophagus (esophageal varices), which can rupture and bleed

• Confusion, drowsiness and slurred speech (hepatic encephalopathy)

• Liver cancer

• End-stage liver failure, which means the liver has stopped functioning

About 20 percent of people with nonalcoholic steatohepatitis will progress to cirrhosis.

Diagnosis

Because nonalcoholic fatty liver disease causes no symptoms in most cases, it frequently comes to medical attention when tests done for other reasons point to a liver problem. This can happen if your liver looks unusual on ultrasound or if you have an abnormal liver enzyme test.

Tests done to pinpoint the diagnosis and determine disease severity include:

Blood tests

• Complete blood count

• Liver enzyme and liver function tests

• Tests for chronic viral hepatitis (hepatitis A, hepatitis C and others)

• Celiac disease screening test

• Fasting blood sugar

• Hemoglobin A1C, which shows how stable your blood sugar is

• Lipid profile, which measures blood fats, such as cholesterol and triglycerides

Imaging procedures

Imaging procedures used to diagnose nonalcoholic fatty liver disease include:

• Plain ultrasound, which is often the initial test when liver disease is suspected.

• Computerized tomography (CT) scanning or magnetic resonance imaging (MRI) of the abdomen. These techniques lack the ability to distinguish nonalcoholic steatohepatitis from nonalcoholic fatty liver disease, but still may be used.

• Transient elastography, an enhanced form of ultrasound that measures the stiffness of your liver. Liver stiffness indicates fibrosis or scarring.

• Magnetic resonance elastography, which combines magnetic resonance imaging with patterns formed by sound waves bouncing off the liver to create a visual map showing gradients of stiffness throughout the liver reflecting fibrosis or scarring.

Liver tissue examination

If other tests are inconclusive, your doctor may recommend a procedure to remove a sample of tissue from your liver (liver biopsy). The tissue sample is examined in a laboratory to look for signs of inflammation and scarring. A liver biopsy may be painful in some patients, and it does have small risks that your doctor will review with you in detail. This procedure is performed by a needle insertion through the abdominal wall and into the liver.

Treatment

The first line of treatment is usually weight loss through a combination of a healthy diet and exercise. Losing weight addresses the conditions that contribute to nonalcoholic fatty liver disease. Ideally, a loss of 10 percent of body weight is desirable, but improvement in risk factors can become apparent if you lose even three to five percent of your starting weight. Weight-loss surgery is also an option for those who need to lose a great deal of weight.

Your doctor may recommend that you receive vaccinations against hepatitis A and hepatitis B to help protect you from viruses that may cause further liver damage.

For those who have cirrhosis due to nonalcoholic steatohepatitis, liver transplantation may be an option. Outcomes of liver transplant in this population group are generally very good.

Potential future treatments

No FDA-approved drug treatment exists for nonalcoholic fatty liver disease, but a few drugs are being studied with promising results.

Alternative medicine

No alternative medicine treatments are proved to cure nonalcoholic fatty liver disease. But researchers are studying whether some natural compounds could be helpful, such as:

• Vitamin E. In theory, vitamin E and other vitamins called antioxidants could help protect the liver by reducing or neutralizing the damage caused by inflammation. But more research is needed.

Some evidence suggests vitamin E supplements may be helpful for people with liver damage caused by nonalcoholic fatty liver disease. But vitamin E has been linked with increased risk of death and, in men, an increased risk of prostate cancer.

• Coffee. In studies of people with nonalcoholic fatty liver disease, those who reported drinking coffee had less liver damage than those who drank little or no coffee. It's not clear how coffee may influence liver damage or how much coffee you'd need to drink in order to benefit.

If you already drink coffee, these results may make you feel better about your morning cup of coffee. But if you don't already drink coffee, this probably isn't a good reason to start. Discuss the potential benefits of coffee with your doctor.

Source: http://www.mayoclinic.org/diseases-conditions/nonalcoholic-fatty-liver-disease/diagnosis-treatment/treatment/txc-20211616