What are the signs and symptoms of fatty liver?
Fatty liver disease rarely causes symptoms until the liver disease is far advanced. Fatty liver usually is found or suspected when:
- Abnormal liver tests are found on routine blood testing
- Fat is seen ultrasonographically when ultrasonography of the abdomen is performed for other reasons, for example, the diagnosis of gallstones
- Infrequently when the liver is enlarged on physical examination of a patient
When the liver disease is far advanced (cirrhosis), signs and symptoms of cirrhosis predominate. These include:
- Excessive bleeding due to the inability of the liver to make blood-clotting proteins
- Jaundice due to the inability of the liver to eliminate bilirubin from the blood
- Gastrointestinal bleeding due to portal hypertension that increases the pressure in intestinal blood vessels
- Fluid accumulation due to portal hypertension that causes fluid to leak from blood vessels and the inability of the liver to make the major blood protein, albumin
- Mental changes (encephalopathy) due to the liver's inability to eliminate chemicals from the body that are toxic to the brain. Coma may occur.
- Liver cancer
What is the difference between nonalcoholic fatty liver and steatohepatitis (NASH)?
As discussed previously, the difference between isolated, nonalcoholic fatty liver and steatohepatitis (NASH) is the presence of inflammation and damage to the liver cells in NASH; in both, the liver has increased amounts of fat. Although about a third of the general population has fatty liver, approximately 10% have NASH. Approximately one third of patients with nonalcoholic fatty liver disease have NASH. Although fatty liver and NASH appear to arise under the same conditions, it does not appear that fatty liver progresses to NASH. Thus, whether a patient is to develop fatty liver versus NASH is determined very early during the accumulation of fat, although it is unclear what factors determine this. It is believed that the inflammation and damage of liver cells are caused by the toxic effects of the fatty acids released by fat cells, but fatty acids in the blood are elevated in both fatty liver and NASH. Perhaps the difference is explained by genetic susceptibility as suggested by preliminary data.
The consequences of fat in the liver depend greatly on the presence or absence of inflammation and damage in the liver, i.e., whether there is fat alone or NASH is present. Isolated fatty liver does not progress to important liver disease. NASH, on the other hand, can progress through the formation of scar (fibrous tissue) to cirrhosis. The complications of cirrhosis, primarily gastrointestinal bleeding, liver failure, and liver cancer, then may occur.
What is the relationship between nonalcoholic fatty liver disease, obesity, and diabetes?
As discussed previously, obesity and diabetes have important roles in the development of fatty liver. Whereas one third of the general population (which includes obese and people with diabetes) may develop nonalcoholic fatty liver disease, more than two thirds of people with diabetes develop nonalcoholic fatty liver disease. Among patients who are very obese and undergoing surgery for their obesity, the majority have nonalcoholic fatty liver disease. Moreover, whereas the risk of NASH is less than 5% among lean persons, the risk is more than a third among the obese. Fatty liver increases both in prevalence as well as severity as the degree of obesity increases. The increases begin at weights that are considered overweight - i.e., less than obese.
What is the relationship between nonalcoholic fatty liver disease and the metabolic syndrome?
The metabolic syndrome is a syndrome defined by the association of several metabolic abnormalities that are believed to have a common cause. These metabolic abnormalities result in
Nonalcoholic fatty liver disease is considered a manifestation of the metabolic syndrome and thus occurs frequently with the other manifestations of the syndrome. Occasionally it may occur without the other abnormalities of the syndrome.