The liver is a highly vascular structure. A great deal of its total mass is composed of blood vessels. Because it is exposed to a high concentration of blood flow, it is at great risk for injury from toxins carried in the blood. The liver can also be damaged from viruses, bacteria, medications, inflammatory diseases such as autoimmune conditions, by products of metabolism and one of the most common causes, idiopathic. If it sounds like idiot, that's because that's exactly how I feel. I can run myriad of tests and never find the exact cause