The most common causes of fatty liver disease are overweight/obesity and alcohol consumption. I have written an article on Practo entitled  'All you need to know about about fatty liver disease.' Do go through for details on evaluation and treatment of fatty liver disease. For fistula visit a general surgeon who can examine and then decide line of treatment

[ ] Fatty liver can be due to alcohol intake or due to obesity ,can be due non Alcoholic fatty liver disease (NAFLD).Generally these are reversible if care taken means need to do physical exercise , need to decrease weight. Quit alcohol if being consumed. There are some medicines which boost up liver and helps in regaining function of liver , advised when required.