Glomerulonephritis (glow-meh-rul-on-nef-fritis) is a kidney disorder that causes inflammation in the small blood vessels of the kidneys, or the renal capillaries. It interferes with the kidney's ability to remove waste products from the blood. It can be caused by an infection or an autoimmune disease. Symptoms can include protein and blood in the urine and swelling. Treatment involves medication, such as antibiotics. If left untreated, it can cause severe chronic kidney disease.