Type of nephritis without pus formation or edema. It may or may not recur. The acute stage involves severe inflammation and back pain, deficient kidney function, swelling, and hypertension. In the subacute stage the kidney enlarges, blood does not reach its surface and red blood cells are damaged (leading to anemia), and its tissue breaks down, releasing excess blood protein into urine. In the chronic stage a small, shriveled, scarred kidney cannot filter nitrogen compounds from the blood, causing uremia. Treatment focuses on symptom relief