Inflamed and swollen kidney, gross specimen. This is a case of glomerulonephritis. This is the acute (rapidly developing) form. Nephritis refers to kidney inflammation. Glomerulonephritis refers to inflammation of the filtering structures of a kidney, its glomeruli (not seen). It is usually caused by a bacterial infection, and may develop from a streptococcal throat infection. Each glomerulus is a tightly coiled network of blood vessels. When a glomerulus is damaged, blood flow is reduced and so the filtration rate is slowed, impairing the blood-cleaning ability of the kidney. Treatment is of any underlying infection, as well as bed rest to allow recovery.