Puerperal infection following vaginal delivery primarily involves the placental implantation site, decidua and adjacent myometrium, or cervicovaginal lacerations. The pathogenesis of uterine infection following cesarean delivery is that of an infected surgical incision. Bacteria that colonize the cervix and vagina gain access to amnionic fluid during labor. Postpartum, they invade devitalized uterine tissue. Parametrial cellulitis next follows with infection of the pelvic retroperitoneal fibroareolar connective tissue. With early treatment, infection is contained within the parametrial and paravaginal tissue, but it may extend deeply into the pelvis.
Fever is the most important criterion or the diagnosis of postpartum metritis. Intuitively, the degree of fever is believed proportional to the extent of infection and sepsis syndrome. Temperatures commonly are 38 to 39°C. Chills that accompany fever suggest bacteremia or endotoxemia. Women usually complain of abdominal pain, and parametrial tenderness is elicited on abdominal and bimanual examination. Leukocytosis may range from 15,000 to 30,000 cells/�L, but recall that delivery itself increases the leukocyte count (Hartmann, 2000). Although an ofensive odor may develop, many women have foul-smelling lochia without evidence for infection, and vice versa. Some other infections, notably those caused by group A j-hemolytic streptococci, may be associated with scant, odorless lochia (Anderson, 2014).
If nonsevere metritis develops following vaginal delivery, then treatment with an oral or intramuscular antimicrobial agent may be suicient (Meaney-Delman, 2015). For moderate to severe infections, however, intravenous therapy with a broad-spectrum antimicrobial regimen is indicated. Improvement follows in 48 to 72 hours in nearly 90 percent of women treated with one of several regimens discussed below. Persistent fever after this interval mandates a careful search for causes of refractory pelvic infection. hese include a parametrial phlegmon-an area of intense cellulitis; an abdominal incisional or pelvic abscess or infected hematoma; and septic pelvic thrombophlebitis. In our experience, persistent fever is seldom due to antimicrobial-resistant bacteria or due to drug side efects. he woman may be discharged home after she has been afebrile for at least 24 hours, and further oral antimicrobial therapy is not needed (French, 2004; Nlackeen, 2015).
Choice of Antimicrobials. Although therapy is empirical, ini tial treatment following cesarean delivery is directed against elements of the mixed lora shown in Table 37-1. For infections following vaginal delivery, as many as 90 percent of women respond to regimens such as ampicillin plus gentamicin. In contrast, anaerobic coverage is included for infections following cesarean delivery (Table 37-2).
In 1979, DiZerega and colleagues compared the efectiveness of clindamycin plus gentamicin with that of penicillin G plus gentamicin for treatment of pelvic infections following cesarean delivery. Women given the clindamycin-gentamicin regimen had a 95-percent response rate, and this regimen is still considered by most to be the standard by which others are measured (F rench, 2004; Mackeen, 2015). Because enterococcal cultures may be persistently positive despite this standard
TABLE 37-2. Antimicrobial Regimens for Pelvic Infections Following Cesarean Delivery
Clindamycin + gentamicin "Gold standard," 90-97% eficacy, once-daily gentamicin dosing acceptable