Kidney inflammation. Light micrograph of kidney tissue in a case of glomerulonephritis. This is a chronic (long-term) form. Nephritis refers to kidney inflammation. Glomerulonephritis refers to inflammation of the filtering structures of a kidney, its glomeruli (round structures, two seen here). In the chronic form, the renal glomeruli and tubes atrophy, turn fibrous, and fail. 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 the underlying cause.