LIVER DISEASE

Causes of Nonalcoholic Fatty Liver Disease (NAFLD)

The cause of nonalcoholic fatty liver disease is not clear. Certain factors tend to increase risk, but in some cases, no risk factors show up. However, NAFLD tends to run in families. It also shows up most often in people who are middle-aged and overweight or obese. These people often have high cholesterol or triglycerides and diabetes or prediabetes (insulin resistance), as well.

Other potential causes of fatty liver disease include:

• Medications
• Viral hepatitis
• Autoimmune or inherited liver disease
• Rapid weight loss
• Malnutrition

Alcoholic Liver Disease (ALD)

More than 15 million people in the U.S and Europe abuse or overuse alcohol. Almost all of them -- 90%-100% -- develop fatty livers. 

Fatty liver can occur after drinking moderate or large amounts of alcohol. It can even occur after a short period of heavy drinking (acute alcoholic liver disease).

Genetics or heredity (what is passed down from parent to child) plays a role in alcoholic liver disease in two ways: It may influence how much alcohol you consume and your likelihood of developing alcoholism. And, it may also affect levels of liver enzymes involved in the breakdown (metabolism) of alcohol.

Other factors that may influence your chances of developing alcoholic fatty liver disease include:

• Hepatitis C (which can lead to liver inflammation)
• An overload of iron
• Obesity
• Diet

There are more than a hundred kinds of liver disease.^[2] The most widely spread are as follows:

• Hepatitis, inflammation of the liver, is caused mainly by various viruses (viral hepatitis) but also by some liver toxins (e.g. alcoholic hepatitis), autoimmunity (autoimmune hepatitis) or hereditary conditions.
• Alcoholic liver disease is any hepatic manifestation of alcohol overconsumption, including fatty liver disease, alcoholic hepatitis, and cirrhosis. Analogous terms such as "drug-induced" or "toxic" liver disease are also used to refer to the range of disorders caused by various drugs and environmental chemicals.
• Fatty liver disease (hepatic steatosis) is a reversible condition where large vacuoles of triglyceride fat accumulate in liver cells. Non-alcoholic fatty liver disease is a spectrum of disease associated with obesity and metabolic syndrome, among other causes. Fatty liver may lead to inflammatory disease (i.e. steatohepatitis) and, eventually, cirrhosis.
• Cirrhosis is the formation of fibrous tissue (fibrosis) in the place of liver cells that have died due to a variety of causes, including viral hepatitis, alcohol overconsumption, and other forms of liver toxicity. Cirrhosis causes chronic liver failure.
• Primary liver cancer most commonly manifests as hepatocellular carcinoma and/or cholangiocarcinoma; rarer forms include angiosarcoma and hemangiosarcoma of the liver. (Many liver malignancies are secondary lesions that have metastasized from primary cancers in the gastrointestinal tract and other organs, such as the kidneys, lungs, breast, or prostate.)
• Primary biliary cirrhosis is a serious autoimmune disease of the bile capillaries.
• Primary sclerosing cholangitis is a serious chronic inflammatory disease of the bile duct, which is believed to be autoimmune in origin.
• Centrilobular necrosis of liver can be caused by leakage of enteric toxins into circulation. Salmonella toxins in ileum have been shown to cause severe damage to liver hepatic cells ^[3]
• Budd–Chiari syndrome is the clinical picture caused by occlusion of the hepatic vein, which in some cases may lead to cirrhosis.
• Hereditary diseases that cause damage to the liver include hemochromatosis, involving accumulation of iron in the body, and Wilson's disease, which causes the body to retain copper. Liver damage is also a clinical feature of alpha 1-antitrypsin deficiency and glycogen storage disease type II.
• In transthyretin-related hereditary amyloidosis, the liver produces a mutated transthyretin protein which has severe neurodegenerative and/or cardiopathic effects. Liver transplantation can provide a curative treatment option.
• Gilbert's syndrome, a genetic disorder of bilirubin metabolism found in about 5% of the population, can cause mild jaundice.
• The liver plays an important role in many bodily functions from protein production and blood clotting to cholesterol, glucose and iron metabolism.
• A variety of illnesses can affect the liver.
• Cirrhosis occurs when normal liver cells are replaced by scar tissue as a result of chronic liver disease.
• Symptoms of liver diseases include weakness and fatigue, weight loss, nausea, vomiting, and yellow discoloration of the skin (jaundice).
• The treatment of a particular liver disease depends on its specific cause.