Why is there hematuria in nephritic syndrome and not in nephrotic syndrome?

Different physiology: The blood vessels in the glomeruli are damaged by inflammation in the nephritic syndrome sufficient for at least a few of them to bleed. They merely leak protein in the nephrotic syndrome, in which obvious inflammation in the classic sense is not visible but protein-retaining molecules in the gbm are lost. Famously, the membranoproliferative glomerulonephritis family produces both syndromes.