<prompt> Answer this question truthfullyWhat is the definition of Nephritic syndrome?  <response>: <reason> Acute nephritic syndrome can be classified according to the etiology of the underlying disease renal vs. non-renal etiology. Similarly, acute nephritis may be classified as idiopathic vs. secondary to other conditions. Finally, diseases may be classified according to the proliferative vs. non-proliferative changes seen on pathology. 