Incision and drainage is the basic tenet of treatment for nearly all infections of the diabetic foot. Streptococcal cellulitis is an exception to this rule. Initial drainage of an abscess can be performed in the emergency department or at the bedside, under local field block or regional ankle block anaesthesia (Fig. 8.1a,b). Drainage means opening up all collections of pus (abscesses), with gentle probing of the superficial and deep tissues for sinus tracts. If present, sinus tracts need to be laid open. Bacteria-laden necrotic tissues are debrided and dependent drainage is established. Sometimes amputation of a toe(s) or ray(s) may be necessary to establish drainage: however, this is best done in the operating theatre. In severe limb-threatening situations, guillotine amputation of the foot may be necessary to stem systemic toxicity. It is important to
emphasize that medical treatment of infection, solely with antibiotics, is insufficient to resolve the majority of diabetic foot infections. In the simplest and most common scenario, surgical debridement of ulcers is the mainstay of treatment. Salvage of the diabetic foot may require aggressive debridement and revascularization.
Gas in the soft tissues is a serious finding requiring an immediate trip to the operating theatre for open drainage of all infected spaces, and intravenous broad-spectrum antibiotics. This presentation is characterized clinically by crepitus, a crackling sensation noted on palpation of the affected soft tissues. This finding is confirmed on
Fig. 8.2 (a) Abscess with cellulitis, right foot. Tense bulla overlying the 5th metatarsophalangeal joint, (b) Incision and drainage, at the bedside.
radiographic examination of the foot. Gas formation by infecting bacteria is common in diabetic foot infections, and is caused by both clostridial and non-clostridial organisms.
One or more incisions may be necessary. Whenever possible, incisions should be directed longitudinally on the foot, so as to avoid the neurovascular structures. It is important to inspect the foot for involvement of the deep compartments, as well as to look for infection that tracks along fascial planes and tendon sheaths. Several trips to the operating theatre may be required. It is incumbent upon the surgeon to plan the incisions with regard to foot function and ultimate surgical repair.
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