ABSTRACT
In tissues adjoining infection, small vessels commonly develop thrombotic occlusion leading to necrosis of the tissue. After desloughing, draining or control of infection, normal arterioles recanalize and form granulation tissue promoting healing of the wound. However in certain mixed infections, so common in diabetic foot, virulent strains of staphylococci and streptococci liberate angiotoxic (necrotizing) substances. These angiotoxic factors like alpha-toxin of staphylococci, along with spreading factors like streptokinase and streptococcal hyaluronidase lead to a rapid extension of necrosis by digestion of fibrin barriers and intracellular ground substance. This is a severe, progressive soft tissue infection, which leads to necrosis of subcutaneous tissues down to the level of muscle fascia. Clinically, it begins with a trivial infection in foot or hand leading to rapidly advancing necrosis with erythema, swelling, and dusky discoloration of the overlying skin with hemorrhagic blisters (Figs 32.1 and 32.2). The occlusive process in the small vessels is exaggerated,
more arterioles are obliterated and the original lesions get converted from trivial to ever enlarging areas of necrosis and gangrene. Creeping advancement of this process of infective obliterative angiopathy leads to devastating lesions within a couple of days. There is also evidence of systemic toxicity in the form of fever, tachycardia,
It spreads like a wild fire
Fig. 32.1: Right leg showing erythema, swelling and dusky discoloration
Fig. 32.2: Left foot and leg showing swelling erythema and hemorrhagic bulla
and hypotension. Urgent fasciotomy, fasciectomy, and if required a major amputation needs to be carried out along with an aggressive medical treatment to prevent such a life threatening situation (Figs 32.3 A and B).
