Which term describes tissue death due to ischemia?

• A. gangrene
• B. subcutaneous emphysema
• C. agonal edema
• D. bacterial translocation

Answer: (A)

Tissue death caused by a loss of blood supply is known as gangrene. When blood flow is severely reduced, tissue becomes hypoxic and can progress to necrosis; if this necrosis is extensive and often exposes the tissue to infection, gangrene develops. It can present in several forms: dry gangrene from prolonged ischemia with mummified, darkened tissue; wet gangrene when necrosis is accompanied by infection and edema, leading to rapid spread; and gas gangrene when anaerobic, gas-forming bacteria invade necrotic tissue, causing gas production and crepitus. Other terms describe different concepts: subcutaneous emphysema is air in the subcutaneous tissues from trauma or infection; agonal edema refers to edema around the time of death; bacterial translocation is the movement of bacteria from the gut to other body sites.