necrosis

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Related to coagulation necrosis: coagulative, liquefaction necrosis, Necrotic tissue

necrosis

1. the death of one or more cells in the body, usually within a localized area, as from an interruption of the blood supply to that part
2. death of plant tissue due to disease, frost, etc.

Necrosis

 

the death within the living organism of individual organs or their component tissues or cells.

A necrosis is classified according to the pathological condition that causes it. Thus, frostbite and burns can cause traumatic necrosis; neurotropic necrosis arises with syringomyelia and the nervous form of leprosy; infarcts and gangrene are associated with circulatory, or ischemic, necrosis; caseous necroses occurring in tuberculosis and syphilis are forms of septic necrosis; and fibrinoid necrosis associated with allergic diseases is a type of allergic necrosis.

Necrosis is accompanied by characteristic changes in the cell and in the intercellular substances. The nucleus shrinks and coagulates, a process known as pycnosis, and the cytoplasm breaks up into clumps. The cell eventually lyses, that is, it degenerates and dissolves. The lysis is due to the activation of the lysosomal hydrolytic enzymes, such as ribonuclease, deoxyribonuclease, and acid phosphatase. The activation of the lysosomes occurs as a result of an increase in the permeability of the cell membranes, changes in the osmotic equilibrium, and acidosis—an abnormal increase in the intracellular hydrogen-ion concentration. Fibrinoid changes appear in the connective tissue, and nerve fibers become fragmented and disintegrate into clumps.

The clinical and morphological manifestations and further consequences of necrosis depend on the localization and distribution of the necrosis and on the mechanisms and conditions of origin. The following types of advanced necrotic conditions can develop: dry necrosis, such as Zenker’s degeneration of infected muscles; colliquative, or liquefactive, necrosis, which occurs for example, when a focus of softening arises in the brain in response to cerebral hemorrhage; gangrene; and bed sores. Necrotic tissue tears away; then, either connective tissue grows through it or the necrotic tissue undergoes autolytic or purulent liquefaction. Finally, the necrotic tissue becomes encapsulated and petrified.

The two most serious consequences of necrosis are a loss of function owing to the death of the structural elements of the necrotic tissues or organs and poisoning caused by the actual presence of a necrotic focus and by the inflammation that arises in response to this presence.

V. V. SEROV

necrosis

[nə′krō·səs]
(medicine)
Death of a cell or group of cells as a result of injury, disease, or other pathologic state.
References in periodicals archive ?
Coagulation necrosis was identified in the epidermis, the superficial papillary dermis, and the whole deep reticular dermis.
Caption: Figure 3: (a) EBUS needle gauge 19 inside lymph node (red arrow); no clear coagulation necrosis identified in the image.
It seems that the injury is of thermal nature and most histologic studies reveal electrothermal coagulation necrosis. It is believed that due to electric discharges in tissue the effect of electroporation occurs as well as changes in configuration of proteins that threaten the integrity and walls of the cell.
The resulting cavitation separates the lung at the periphery of the persisting central zone of coagulation necrosis. The histopathology of this transition lesion forms the basis for the analogous radiological air crescent sign, which is an imaging indicator of late IPA.
Several approaches have been used to increase the diameter of coagulation necrosis or tissue breakdown achieved during RFA.
Cellular injury consisted of various combinations of contraction bands, hemorrhage, myocyte hypereosinophilia, nuclear pyknosis, and coagulation necrosis but no neutrophil infiltration.
RFA involves applying thermal energy to a probe inserted into or near a tumor mass to produce coagulation necrosis in a controlled fashion.
Patients with necrotizing sialometaplasia exhibit a spectrum of histologic findings, ranging from coagulation necrosis of the salivary gland acini in early lesions to squamous metaplasia of ducts and reactive fibrosis in late lesions.
This process is distinct from "coagulation necrosis," which is caused by exposure to mineral acids.
Thus, fast and homogeneous tissue heating and subsequently coagulation necrosis occur.[sup][8],[9] This study summarized a 5-year single-center experience regarding the performance of RFA and MWA to treat adrenal metastases, originating from NSCLC.
Electromagnetic waves at frequencies of 900-2450 MHz are used to induce coagulation necrosis. Polar molecules (mainly water dipoles) try to realign themselves with the direction of current in an electromagnetic field.
INTRANODAL NECROSIS (Cystic & Central/ Coagulation): Intranodal necrosis may be seen as a cystic (cystic or liquefaction necrosis) or echogenic (coagulation necrosis) area within the node.