Accumulation of fat in liver cells which can be detected by radiological imaging or liver biopsy is called fatty liver disease. Detection by liver biopsy is still the gold standard. In a liver biopsy, by definition, more than 5% of liver cells should show fat accumulation. Currently for diagnosis liver biopsy is not done routinely. Radiological imaging methods are more convenient and less risky and hence more often done. Ultrasound and CT scans detect fatty liver only when more than 30% of liver cells have fat in them. Advance MRI scans can detect fatty liver when more than 3% of liver cells have fat. Fibroscan� with CAP parameters are also being used to detect fat in liver and scarring of liver tissues.
What are the causes of fatty liver?
The causes of fatty liver disease are classified as alcoholic and non-alcoholic. Earlier, alcohol consumption of a minimum of 21 drinks per week for men and 14 drinks per week over a 2-year period was considered significant. But these are western standards and Indian data are not actually available. No minimum amount of alcohol consumption is considered safe now.
Alcohol has an additive effect with other causes of liver injury. Among the non-alcoholic causes, the most common (~70%) are being overweight, obesity and diabetes (~75%). The epidemic of obesity and diabetes has increased the number of people with fatty liver disease. And the use of alcohol even in minimal quantities in these conditions increases the risk of serious liver injury. Fatty liver can be present even before diabetes develops in overweight/obese people.
Other causes of fatty liver disease are endocrine diseases (thyroid disorders, etc.), chronic viral hepatitis, blood lipid (cholesterol) disorders (20-80%), medications (steroids, etc.), genetic diseases (Wilson�s disease, etc.), liver diseases during pregnancy and other rare disorders.
There are two types of non-alcoholic fatty liver diseases (NAFLD). Non-alcoholic fatty liver (NAFL) is the benign condition in which only fat accumulates without inflammation of the liver tissue. The non-alcoholic steatohepatitis (NASH) is where fat accumulates along with liver inflammation leading to liver damage and in the long run, it turns into cirrhosis. Many patients with NAFL never develop NASH although some do.
Should one be worried about the fatty liver disease?
Non-alcoholic fatty liver disease was first described in 1980 by Ludwig J of Mayo clinic. Even then it was clear that a patient with fatty liver has the risk of liver inflammation and scarring which can ultimately lead to cirrhosis and liver failure.
The author�s conclusion in 1980 � �we know of no effective treatment� � still holds true. Furthermore, it has become clear that the major cause of death in patients with non-alcoholic fatty liver disease is cardiovascular (heart and artery related)- traditionally associated with diabetes, high blood pressure, abnormal cholesterol in blood and cigarette smoking, etc. World over, the cases of obesity, diabetes, high blood pressure (the so-called lifestyle diseases) are increasing, as are the cases of non-alcoholic fatty liver disease. So, we are not only worried about just liver disease but also about major non-liver related complications.
What are the signs and symptoms of fatty liver?
Most of the people (48-100%) have no complaints about fatty liver and the problem is detected during routine tests for other diseases. Uncommon complaints are of mild pain in the abdomen, noticeable fatigue and decrease in work capacity. In the later stage, the symptoms could manifest as cirrhosis and liver failure like fluid in the abdomen, change in behaviour/ consciousness, bleeding, etc. Features of underlying diseases like diabetes may also be present with such symptoms. Usually the liver size increases and later on the spleen size also increases. Other features are redness of palms and soles, spiders like blood vessels over the torso, etc.
What are the investigations needed?
Tests like liver function test, for hepatitis B and hepatitis C, blood sugar levels, thyroid function, serum cholesterol levels, etc., are usually done. Radiological tests like an ultrasound scan of the abdomen, sometimes CT scan and MRI scans of the abdomen, Fibroscan, etc., can be done. As people having NAFLD are at high risk of heart disease and strokes, tests like ECG, echocardiography, treadmill test, etc., are also prescribed for risk evaluation. Liver biopsy is usually reserved for people when other causes of liver disease cannot be excluded by other tests. As the test is invasive and carries a small but definitive risk of adverse effects, it is usually reserved for the last.
What are the treatment options?
Currently, there is no cure for NASH. Treatment options centres around controlling the conditions causing NASH. Many drugs are being tested, some showing promising early results and should be made available in the next few years. The mainstay of treatment is lifestyle modifications. Losing weight is the first advice given. Weight loss has to be gradual. Too rapid weight loss worsens liver disease. Weight loss should be tried both with exercise and nutritional advice. Alcohol use has to stop completely. Then comes treatment of diabetes, if present, and any other associated conditions. Drugs like Vitamin E and Saroglitazar have shown benefit in a selected group of people. Please use medicines only under medical supervision. You will also be advised to get yourself vaccinated against Hepatitis B and sometimes also against Hepatitis A.
What is the prognosis of NAFLD?
As stated above, NAFL is benign and in most of the people does not progress to NASH.
Currently, it is difficult to predict the progression to NASH and also which individual with NASH will progress further to develop cirrhosis and its complications. The good news is that studies have shown most people with NASH will live as long as people without NASH. However, some people will develop complications. Older people with NASH and diabetes are at increased risk. People with NASH also are at increased risk of heart disease. So, lifestyle modifications are always advised to people with NAFLD. Maintain a healthy weight, exercise regularly and avoid alcohol.