Light micrograph section through human kidney tissue showing diffuse capillary glomerulonephritis. Nephritis is characterised by inflammation of the capillary loops in the glomeruli of the kidney. It occurs in acute, subacute and chronic forms and may be secondary to infection. Diffuse glomerulonephritis is a severe form of the disease with prolific changes in more than half the glomeruli. The glomerulus appears hypercellular and the capillaries are narrowed or occluded.