A condition in which the tissues in the kidney become inflamed and have problems filtering waste from the blood. Nephritis may be caused by infection, inflammatory conditions (such as lupus), certain genetic conditions, and other diseases or conditions. It may also be caused by taking certain medicines or being exposed to certain chemicals. Signs and symptoms include blood and protein in the urine; high blood pressure; swelling of the face, hands, feet, and legs; fatigue; and anemia. If not treated or controlled, nephritis may lead to kidney damage and kidney failure. Also called glomerulonephritis.