A medical episode is a health event or series of events that is distinct from your normal state of health. It has a clear beginning and end and while it can be related to a chronic illness, a medical episode is separate. For example, you may have chronic arthritis of the knee, but suddenly an acute flare-up makes you unable to walk. The acute flare-up would have a distinct beginning, would run a distinct length of time, and will likely revert back to the chronic state; this would be considered a medical episode.