Wet gangrene is characterized by its moist appearance, gross swelling, and blistering. Wet gangrene is a surgical emergency. Pt presented in the ED with wet gangrene, and dry gangrene post op.
(Neschis, 2016)
Ischemia sufficient to threaten a limb occurs when arterial blood flow is insufficient to meet the metabolic demands of resting muscle or tissue. Once patient’s body is unable to maintain the metabolic needs, it goes into anaerobic metabolism, which is seen in labs as high lactic acid. Acute thrombosis of sites of stenosis in which the blood flow impairment was hemodynamically significant can occur and present with acute symptoms., such as pain, pallor, paresthesias, paralysis, pulselessness, and poikilothermia(coldness). Symptoms of parethesias and paralysis may indicate advanced ischemia that is affecting nerve pathways of the extremity. Patient had ischemic ulcer in L foot, and signs of parethesias, pulselessness, and pain.
(Baird, 2016 p590, Porth, 2011 p415)
The presence of ischemia from occlusion to a lower extremity influences the timing of revascularization, debridement, and definitive coverage/closure. Wounds will not be able to heal as well as a result of ischemia and may lead to necrotizing of the soft tissue. It may come in the form of cellulitis, myositis, and fasciitis.
Necrotizing cellulitis include anaerobic infection and Meleny’s syngergistic gangrene. Anaerobic cellulitis can be divided into clostridial anaerobic cellulitis and non-clostridial anaerobic cellulitis. Clostridial anaerobic cellulitis is usually caused by C. perfringens. These organisms may be introduced into the subcutaneous tissue via trauma, surgical contamination, or spread of infection from the bowel to the perineum, abdominal wall, or lower extremities. The presence of foreign debris and necrotic tissue in a wound provides an appropriate environment for the proliferation of clostridial cells. Nonclostridial anaerobic cellulitis is caused by various non-spore-forming anaerobic bacteria(Bacterioides specis, peptostreptococci, and others) either alone of mixed with facultative organisms such as coliform bacilli, streptococci, staphylococci. Meleney’s synergistic gangrene is a rare infection that occurs in post-operative patient. It’s characteristic is a slowly expanding ulceration that is confined to the superficial fascia and results from a synergistic interaction between S. aureus and microaerophillic streptococci.

Necrotizing myositis, also known as spontaneous gangrenous myositis is relatively rare. It is a necrotizing infection of skeletal muscle caused by group A Streptococcus or other beta-hemolytic streptococci. It may be preceded with skin abrasions or blunt trauma. The infection will progress over several hours and involve muscle groups and soft tissue. If the patient develops streptococcal toxic shock syndrome, then they have an onset of hypotension. These patients will not have evidence of gas formation in tissue on physical or radiographic examination.
Necrotizing fasciitis in an infection of the deeper tissues that results in progressive destruction of the muscle fascia and overlying subcutaneous fat. Infection is usually spread along the muscle fascia due to it’s relatively poor blood supply. The process progresses rapidly over several days, from erythematous area to change in skin color from red-purple to patches of blue-gray. Within three-five days onset, skin breakdown with bullae will occur and frank cutaneous gangrene can be seen. By this time, the involved area is no longer tender but has become anesthetic secondary to thrombosis of small blood vessels and destruction of superficial nerves in the subcutaneous tissue. There are two types of necrotizing fasciitis.
Type I of necrotizing fasciitis is a mixed infection caused by aerobic and anaerobic bacteria. Risk factors include diabetes, PVD, immune compromised, and recent surgery. Type II necrotizing fasciitis is generally monomicrobial. It is caused by group A Streptococcus or other beta-hemolytic streptococci that is either alone or in combination with other pathogens, most commonly S. aureus. Patient’s culture came back with growth of Staphlococcus aureus.
(Stevens, 2016)
The Society for Vascular Surgery Lower Extremity Threatened Limb Classification System, WIfI, is a system for classifying the severity of limb threat that is intended to reflect clinical considerations that impact management and amputation risk. WIfI is an acronym for wound, ischemia, and foot infection. Each category has a different grade.
For wound, a grade 0 is rest pain; no wound; no ulcer; no gangrene. Grade 1 is a small shallow ulcer(s) on distal leg or foot, any exposed bone is only limited to distal phalanx(ie. Minor tissue loss, limb salvageable with possible simple digital amputation or skin coverage). Grade 2 involves a deeper ulcer on distal leg or foot with exposed bone, joint, or tendon, or shallow heel ulcer without involvement of the calcaneus( ie. Major tissue loss: salvageable with >3 digital amputations or standard transmetatarsal amputation plus skin coverage). Grade 3 is an extensive deep ulcer of the forefoot and/or midfoot, or full thickness heel ulcer with or without involvement of the calcaneus(ie. Extensive