Persistent postoperative fever
Resistant microorganism
The most common cause of a persistent fever after initiating antibiotic therapy is a resistant microorganism. There are potential gaps in coverage for the antibiotic regimens commonly used to treat postcesarean endometritis (TABLE 3).1,4 Assuming there is no other obvious cause for treatment failure, I recommend that therapy be changed to the triple combination of metronidazole plus ampicillin plus gentamicin (or aztreonam). The first drug provides superb coverage against anaerobes; the second covers enterococci. Gentamicin or aztreonam cover virtually all aerobic Gram-negative bacilli likely to cause postcesarean infection. I prefer metronidazole rather than clindamycin in this regimen because, unlike clindamycin, it is less likely to trigger diarrhea when used in combination with ampicillin. The 3-drug regimen should be continued until the patient has been afebrile and asymptomatic for approximately 24 hours.1,3,4
Wound infection
The second most common reason for a poor response to initial antibiotic therapy is a wound (surgical site) infection. Wound infections are caused by many of the same pelvic pathogens responsible for endometritis combined with skin flora, notably Streptococcus and Staphylococcus species, including methicillin-resistant Staphylococcus aureus (MRSA).1,4
Wound infections typically take one of two forms. The first is an actual incisional abscess. The patient is febrile; the margins of the wound are warm, indurated, erythematous, and tender; and purulent material drains from the incision. In this situation, the wound should be opened widely to drain the purulent collection. The fascia should then be probed to be certain that dehiscence has not occurred. In addition, intravenous vancomycin (1 g every 12 h) should be included in the antibiotic regimen to ensure adequate coverage of hospital-acquired MRSA.1,4
The second common presentation of a wound infection is cellulitis. The patient is febrile, and there is a spreading area of erythema, warmth, and exquisite tenderness extending from the edges of the incision; however, no purulent drainage is apparent. In this second scenario, the wound should not be opened, but intravenous vancomycin should be added to the treatment regimen.1,3,4
A third and very rare form of wound infection is necrotizing fasciitis. In affected patients, the margins of the wound are darkened and necrotic rather than erythematous and indurated. Two other key physical findings are crepitance and loss of sensation along the margins of the wound. Necrotizing fasciitis is truly a life-threatening emergency and requires immediate and extensive debridement of the devitalized tissue, combined with broad spectrum therapy with antibiotics that provide excellent coverage against anaerobes, aerobic streptococci (particularly group A streptococci), and staphylococci. The requirement for debridement may be so extensive that a skin graft subsequently is necessary to close the defect.1,4
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