Gangrene overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Edzel Lorraine Co, D.M.D., M.D.
Overview
Gangrene is a medical condition that involves necrosis and ischemia of a body tissue, mostly occurring in the digits or extremities. It usually appears as a black discoloration and sloughing of tissues. There are three main types of gangrene, namely wet gangrene, dry gangrene, and gas gangrene.
Historical Perspective
Gangrene originated from a Greek word that meant mortification of a human body part. It was first used as a noun in the British Isles during the 16th century. Surgeons most often used it to refer to the cure of external human conditions.
Classification
There are three main types of gangrene which include wet, dry, and gas gangrene. Sometimes it can be classified according to its site.
Pathophysiology
The three main types of gangrene occur in different mechanisms. Dry gangrene involves a reduction in the perfusion of the arteries results in the compensatory dilation of the arterioles, which eventually results in distal edema, and damage of the endothelial tissue. In wet gangrene, saprogenic microorganisms (Bacillus fusiformis, or Clostridium perfringens) infect the tissues, thereby causing an emission of a foul odor and edema. Multiplication of exotoxins from Clostridium perfringens and group A steptococcus is responsible for the local tissue destruction and systemic infection in gas gangrene.
Causes
According to Hippocratic physicians, gangrene is brought about by three reasons. These include wound constriction that is followed by hemorrhage, body part compression, and necrosis due to bandages.
Differentiating Gangrene from other Diseases
Gangrene can have several mimicking conditions despite the unique presence of necrotic tissue.
Epidemiology and Demographics
Ischemic or dry gangrene is commonly associated with peripheral artery disease (PAD). The most advanced stage of PAD is critical limb ischemia/ chronic limb-threatening ischemia, and it has an incidence rate of 1% in the United States. Gas gangrene is a rare condition, with an annual record of 1000 cases in the United States, 50% of which are due to traumatic injuries, 30% due to post-operative complications, and the rest is due to infections.
Risk Factors
There are several risk factors for gangrene and these include penetrating trauma, blunt trauma, recent surgery, obesity, alcoholism, mucosal breach, skin breach, and immunosuppression.
Natural History, Complications, and Prognosis
Amputation and death are the most common consequence of critical limb ischemia/ chronic limb-threatening ischemia. Gas gangrene has higher fatality rate, ranging from 25% to 100%, if treatment is inadequate or delayed. Increased age, several comorbidities present, and involvement of trunk lead to a poor prognosis.
Diagnosis
History and Symptoms
Chronic limb pain is the usual chief complaint of patients who developed gangrene.
Physical Examination
Patients with gangrene may have varying presentations depending on the type of gangrene they have.
Laboratory Findings
Evaluation of patients with ischemic gangrene is more focused on targeting the risk factors which include hyperlipidemia, diabetes, and renal failure. Laboratory tests to deal with these risk factors are usually requested for ischemic gangrene. Wet gangrene and gas gangrene are assessed with the help of cultures.
X-ray
X-rays are utilized in the evaluation of gas gangrene to identify any present subcutaneous gas.