Chapter 135. Gas Gangrene and Other Clostridial Infections (Part 3)

Spontaneous nontraumatic clostridial myonecrosis (gas gangrene). A man in his 50s presented with severe pain in the right upper extremity. Over several hours, he developed progressive swelling and discoloration in that extremity (A), with hemorrhagic ecchymoses and bullae (B). Grams stain of aspirate from bullous lesions revealed gram-positive bacilli (C). The patient underwent amputation of the extremity. Tissue Grams stain (D) also showed gram-positive bacilli, and surgical cultures grew C. septicum. Subsequent evaluation of the patient led to the diagnosis of invasive colonic carcinoma. (Images used with permission of Stephen Calderwood, MD, andwww.idimages.org.)Clostridia have been isolated from suppurative infections...
Nội dung trích xuất từ tài liệu:
Chapter 135. Gas Gangrene and Other Clostridial Infections (Part 3) Chapter 135. Gas Gangrene and Other Clostridial Infections (Part 3) Spontaneous nontraumatic clostridial myonecrosis (gas gangrene). Aman in his 50s presented with severe pain in the right upper extremity. Overseveral hours, he developed progressive swelling and discoloration in thatextremity (A), with hemorrhagic ecchymoses and bullae (B). Grams stain ofaspirate from bullous lesions revealed gram-positive bacilli (C). The patientunderwent amputation of the extremity. Tissue Grams stain (D) also showedgram-positive bacilli, and surgical cultures grew C. septicum. Subsequentevaluation of the patient led to the diagnosis of invasive colonic carcinoma.(Images used with permission of Stephen Calderwood, MD, andwww.idimages.org.) Clostridia have been isolated from suppurative infections of the femalegenital tract, particularly tuboovarian and pelvic abscesses. The major speciesinvolved has been C. perfringens. Most of these suppurative infections are mild,with no evidence of uterine gangrene. C. perfringens has been isolated from asmany as 20% of diseased gallbladders at surgery. One clinical syndrome,emphysematous cholecystitis, is caused by clostridial species at least 50% of thetime. In this syndrome, gas forms in the biliary radicles and the wall of thegallbladder. Emphysematous cholecystitis is seen most often in diabetic patients.Although the mortality rate in this entity is higher than in more common forms ofcholecystitis, there is no evidence of myonecrosis. Clostridia are among the many organisms found in empyema fluid orisolated by transtracheal aspiration from patients with lung abscesses. There is nounique clinical clue to the presence of clostridia (as opposed to other organisms) inthese infections. C. perfringens has been reported as a cause of empyema arisingfrom aspiration pneumonia, pulmonary emboli, and infarction. However, themajority of cases of clostridial empyema are secondary to trauma. Skin and Soft Tissue Infections Various categories of traumatic wound infections due to clostridia havebeen described: simple contamination, anaerobic cellulitis, fasciitis with orwithout systemic manifestations, and anaerobic myonecrosis. Simple Contamination Clostridia are cultured most often from wounds in the absence of clinicalsigns of sepsis. As many as 30% of battle wounds are contaminated by clostridiawithout signs of suppuration, and 16% of penetrating abdominal wounds yieldclostridia on culture despite treatment with cephalothin and kanamycin. In cases oftrauma, clostridia are isolated with equal frequency from suppurative and well-healing wounds. Thus the diagnosis of clostridial infection should be based onclinical rather than bacteriologic criteria. Localized Infection of the Skin and Soft Tissue Without Systemic Signs This condition, originally referred to as anaerobic cellulitis, is a localizedinfection involving the skin and soft tissue and is due to clostridia alone or withother bacteria. There are no systemic signs of toxicity, although the infection mayinvade locally, producing necrosis. These infections tend to be relatively indolent,spreading slowly to contiguous areas. Localized infections are relatively free ofpain and edema. Perhaps because of the lack of edema, gas that is limited to thewound and the immediately surrounding tissue may be more evident than in gasgangrene. In these localized infections, gas is never found intramuscularly.Cellulitis, perirectal abscesses, and diabetic foot ulcers are typical infections fromwhich clostridial species can be isolated. If inadequately treated, these localizedinfections advance by extension through subcutaneous tissue and fascial planesinto muscle and may produce severe systemic disease with signs of toxemia. A localized form of suppurative myositis has been described in heroinaddicts. These patients develop local pain and tenderness in discrete areas(particularly the thigh and forearm), with the subsequent appearance of fluctuanceand crepitance that require surgical drainage. The unusual aspect of theseinfections is that they remain localized without systemic signs of toxicity.Moreover, the affected local areas are not necessarily sites of trauma or heroininjection. Pathologic examination reveals subcutaneous abscesses, purulentmyositis, and fasciitis from which clostridia are recovered in pure culture; onoccasion, mixed infections involving aerobes and anaerobes are found. Woundbotulism has been reported in association with the injection of black tar heroin. Spreading Cellulitis and Fasciitis with Systemic Toxicity This condition involves di ...