I know this dude who has encephalopathy. what is that?

Brain dysfunction: Encephalopathy is a general term that refers to any disturbance in brain function such as level of conciousness, attention, or orientation to time, place or person. It is often used to describe a patient who is disoriented, confused, drowsy, or agitated. This may be due to process in the brain (e.g. Stroke, tumor, hemorrhage, infection, etc) or outside the brain (e.g. Liver or renal disease, etc).

Brain malfunction: Encephalopathy is a non specific term for a syndrome where the brains higher functions like memory, concentration, attention, level of alertness are all impaired. Symptoms can range from delirium and confusion to coma and seizures. Causes vary and include basically any illness that affects the brain or a major organ system that keeps the environment the brain operates in normal.