1. CLOSTRIDIAL MYONECROSIS (GAS GANGRENE)
ESSENTIALS OF DIAGNOSIS
Sudden onset of pain and edema in and around a contaminated wound.
Prostration and systemic toxicity.
Brown to blood-tinged watery exudate, with skin discoloration of surrounding area.
Gas in the tissue by palpation or radiograph.
Gram-positive rods in culture or smear of exudate.
Gas gangrene or clostridial myonecrosis is a life-threatening muscle infection produced by any one of several clostridia (Clostridium perfringens, C ramosum, C bifermentans, C histolyticum, C novyi, etc). Trauma and injection drug use are common predisposing conditions. Toxins produced in devitalized tissues under anaerobic conditions result in shock, hemolysis, and myonecrosis.
The onset is usually sudden, with rapidly increasing pain in the affected area, hypotension, and tachycardia. Fever is present but is not proportionate to the severity of the infection. In the last stages of the disease, severe prostration, stupor, delirium, and coma occur.
The wound becomes swollen, and the surrounding skin is pale. There is a foul-smelling brown, blood-tinged serous discharge. As the disease advances, the surrounding tissue changes from pale to dusky and finally becomes deeply discolored, with coalescent, red, fluid-filled vesicles. Gas may be palpable in the tissues.
Gas gangrene is a clinical diagnosis, and empiric therapy is indicated if the diagnosis is suspected. Radiographic studies may show gas within the soft tissues, but this finding is not sensitive nor specific. The smear shows absence of neutrophils and the presence of gram-positive rods. Anaerobic culture confirms the diagnosis.
Other bacteria can produce gas in infected tissue, eg, enteric gram-negative organisms, or anaerobes.
Adequate surgical debridement and exposure of infected areas are essential, with radical surgical excision often necessary. Penicillin, 2 million units every 3 hours intravenously, is an effective adjunct. Clindamycin may decrease the production of bacterial toxin, and some experts recommend the addition of clindamycin, 600–900 mg every 8 hours intravenously, to penicillin. Hyperbaric oxygen therapy has been used empirically but must be used in conjunction with administration of an appropriate antibiotic and surgical debridement.
et al. Therapeutic targets in necrotizing soft tissue infections. Intensive Care Med. 2017;43:1717.
et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clin Infect Dis. 2014;59:147.
et al. Interventions for treating gas gangrene. Cochrane Database Syst Rev. 2015;12:CD010577.
2. CLOSTRIDIUM SORDELLII TOXIC SHOCK SYNDROME
ESSENTIALS OF DIAGNOSIS...