Gangrene
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Gangrene

Fluid And Haemodynamic Disorders

Pathology

Gangrene

Gangrene (or gangrenous necrosis) is a form of necrosed tissue with super added putrefaction.

It can be explained as a type of necrosis caused by a critically insufficient blood supply. This potentially life-threatening condition may occur after an injury or infection, or in people suffering from any chronic health problem affecting blood circulation. The primary cause of gangrene is reduced blood supply to the affected tissues, which results in cell death. Diabetes and long-term smoking increase the risk of suffering from gangrene. Gangrene is not a communicable disease; it does not spread from person to person, though the infection associated to some forms can. The types of gangrene differ in symptoms, and include dry gangrene, wet gangrene, gas gangrene, internal gangrene, and necrotizing fasciitis. Surgical removal of gangrenous tissue and antibiotics and in some cases amputations are the mainstays of treatment for gangrene. After the gangrene is treated, the underlying cause is addressed. This includes lifestyle modification such as smoking cessation, better control of diabetes, revascularization or, rarely, medical therapy to stop vascular spasm or the production of cold-induced vascular obstruction by cold-precipitated cryoglobulins.

Gangrene Image

The type of necrosis is coagulative due to ischemia- Ischemia or ischemia is a restriction in blood supply to tissues, causing a shortage of oxygen and glucose needed for cellular metabolism (to keep tissue alive).

The Three main types of Gangrene are:

  1. Dry Gangrene
  2. Wet Gangrene
  3. Gas Gangrene

1. Dry Gangrene

Dry gangrene is a form of coagulative necrosis that develops in ischemic tissue, where the blood supply is inadequate to keep tissue viable. This form of gangrene begins in the distal part of limb. For example in toes and feet due to arteriosclerosis.

Pathological Changes:

The affected area is dark black, shrunken and dry. The line of separation usually brings about the complete separation. The line of separation consists of granulation tissue.


2. Wet Gangrene

This occurs mostly in tissues which are moist. Eg: Mouth, lung, cervix, etc.

Pathological Changes:

The affected area is edematous, dark, putrid, swollen, soft, rotten. No clear line of demarcation. Has a poor prognosis (compared to dry gangrene) due to sepsis resulting from the free communication between infected fluid and circulatory fluid. Microorganisms (Clostridium perfringens or Bacillus fusiformis, for example), which cause tissue to swell and emit a fetid smell. The toxic products formed by bacteria are absorbed, causing systemic manifestation of sepsis and finally death.


3. Gas Gangrene

This special type of gangrene caused due to clostridia.Gas gangrene is a bacterial infection that produces gas within tissues. It can be caused by Clostridium, most commonly alpha toxin-producing C. perfringens, or various nonclostridial species. Infection spreads rapidly as the gases produced by bacteria expand and infiltrate healthy tissue in the vicinity. Because of its ability to quickly spread to surrounding tissues, gas gangrene should be treated as a medical emergency. Gas gangrene is caused by bacterial exotoxin-producing clostridial species, which are mostly found in soil, and other anaerobes such as Bacteroides and Anaerobic Streptococci. These environmental bacteria may enter the muscle through a wound and subsequently proliferate in necrotic tissue and secrete powerful toxins, which destroy nearby tissue, generating gas at the same time. Gas gangrene can cause necrosis, gas production, and sepsis. Progression to toxemia and shock is often very rapid.

Pathological Changes:

The affected area is swollen, crepitant, painful and edematous due to accumulation of gas bubbles in tissue. The affected area is foul smelling.


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