Fibrinoid necrosis

Fibrinoid necrosis is a specific type of necrosis or cell death, that occurs in certain conditions such as rheumatic fever, polyarteritis nodosa, and malignant hypertension. It is characterized by the deposition of fibrin-like proteinaceous material in the arterial walls.

Overview

Fibrinoid necrosis is a morphologic term that refers to a type 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 arteries. 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.

Pathogenesis

The pathogenesis of fibrinoid necrosis involves the deposition of immune complexes in the walls of arteries. These immune complexes trigger an inflammatory response, which leads to the activation of the coagulation cascade and the formation of fibrin. The fibrin then leaks out of the vessels and deposits in the arterial walls, leading to the characteristic appearance of fibrinoid necrosis.

Clinical Significance

Fibrinoid necrosis is a hallmark of several diseases, including rheumatic fever, polyarteritis nodosa, and malignant hypertension. In rheumatic fever, fibrinoid necrosis can occur in the heart valves, leading to valvular heart disease. In polyarteritis nodosa, it can occur in the small and medium-sized arteries, leading to organ damage. In malignant hypertension, it can occur in the renal arterioles, leading to renal failure.

Diagnosis

The diagnosis of fibrinoid necrosis is made by histopathological examination of a biopsy specimen. The characteristic appearance of fibrinoid necrosis is a bright pink and amorphous appearance in H&E stains.

Treatment

The treatment of diseases associated with fibrinoid necrosis involves managing the underlying condition. This may involve the use of anti-inflammatory drugs, immunosuppressive drugs, or antihypertensive drugs, depending on the specific disease.

See Also

• Necrosis
• Rheumatic fever
• Polyarteritis nodosa
• Malignant hypertension

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  Fibrinoid necrosis
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  Churg-Strauss syndrome - high magnification
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  Histopathology of a rheumatoid nodule