Which of the following type of necrosis is seen in blood vessel due to immune complex mediated damage?
Fibrinoid necrosis is a special form of necrosis usually seen in immune reactions involving blood vessels. This pattern of necrosis typically occurs when complexes of antigens and antibodies are deposited in the walls of aeries. Deposits of these "immune complexes," together with fibrin that has leaked out of vessels, result in a bright pink and amorphous appearance in H&E stains, called "fibrinoid" (fibrin-like) by pathologists. Seen in Type III hypersensitivity, microscopic polyangiitis, vegetation of Libman Sack Endocarditis, malignant hypeension. Coagulative necrosis is a form of necrosis in which the architecture of dead tissues is preserved for a span of at least some days . The affected tissues exhibit a firm texture. Ischemia caused by obstruction in a vessel may lead to coagulative necrosis of the supplied tissue in all organs except the brain. A localized area of coagulative necrosis is called an infarct. Liquefactive necrosis, in contrast to coagulative necrosis, is characterized by digestion of the dead cells, resulting in transformation of the tissue into a liquid viscous mass. It is seen in focal bacterial or, occasionally, fungal infections, because microbes stimulate the accumulation of leukocytes and the liberation of enzymes from these cells. \The necrotic material is frequently creamy yellow because of the presence of dead leukocytes and is called pus. For unknown reasons, hypoxic death of cells within the central nervous system often manifests as liquefactive necrosis. Caseous necrosis is encountered most often in foci of tuberculous infection. The term "caseous" (cheeselike) is derived from the friable white appearance of the area of necrosis. On microscopic examination, the necrotic area appears as a structureless collection of fragmented or lysed cells and amorphous granular debris enclosed within a distinctive inflammatory border; this appearance is characteristic of a focus of inflammation known as a granuloma
Coagulative necrosis
Liquefactive necrosis
Fibrinoid necrosis
Caseous necrosis
NEET 2019