Any inflammatory disease has degenerative, exudative and proliferative changes, but some inflammatory diseases are predominantly degenerative, some are predominantly exudative, and some are predominantly proliferative. Degenerative inflammation is often seen in acute inflammatory diseases, often caused by severe infection or poisoning, such as acute severe hepatitis B, when there is extensive necrosis of liver cells, while exudative and proliferative changes are often mild. Metaplastic inflammation such as epidemic B encephalitis, in which there is extensive degeneration and necrosis of nerve cells and less hyperplasia and exudation. Metaplastic inflammation often occurs in parenchymal organs such as the liver, kidneys, heart, and brain, causing dysfunction.