Antibiotic failure may point to missed pelvic mass. (Reserve Heparin for Very Large Thrombi).
Roughly 55% of cases of antibiotic failure in pelvic infections are due to an infected mass of some type, such as an abscess, septic pelvic thrombophiebitis, hematoma, or a retained placenta, said Dr. Gibbs, professor and chair of ob.gyn. at the university.
The three lesser causes of poor response to antibiotic therapy with clindamycin plus an aminoglycoside or a similarly broadspectrum regimen each account for about 15% of cases. These are the presence of resistant organisms; existence of another source of infection, such as pyelonephritis, pneumonia, or a catheter; or an infection that for no apparent reason fails initially to respond to appropriate antibiotic therapy but comes around with continued treatment and eventually is cured.
Given the likelihood that a woman whose infection has failed to respond to broad-spectrum antibiotics probably has an infected pelvic mass, it makes sense to routinely search for such a mass in nonresponders. Often, it can be felt during a pelvic examination. A pelvic mass may be missed if it's located retroperitoneally or behind the uterus, or if the patient is exquisitely tender.
Failure to detect a mass upon exam often triggers an imaging study Ob.gyns. can do this themselves using pelvic ultrasound, or a referral to a radiologist is in order.
Three therapeutic options exist when the diagnosis is a frank pelvic abscess or an infected pelvic mass believed to be on its way to becoming one. One is continued intravenous broad-spectrum antibiotic therapy. Although classic teaching holds that abscesses don't respond to antimicrobial therapy, this is clearly not the case. One need look no further than the multiple studies of patients with tuboovarian abscesses up to 5-7 cm in size, where response rates of up to 80% have been reported, Dr. Gibbs said.
The second option is percutaneous drainage under ultrasound or CT guidance. Multiloculated pelvic abscesses may not be amenable to percutaneous drainage in which surgical drainage is required.
The other big concern when an infected pelvic mass is identified, besides pelvic abscess, is septic pelvic thrombophiebitis. The classic presenting pattern is a woman whose pelvic tenderness and constitutional symptoms of pelvic infection are resolving in the face of broad-spectrum antibiotic therapy, but who continues to experience a high and spiking fever. In this case, the diagnosis is made after ruling out other possible causes.
Until a few years ago, standard therapy for septic pelvic thrombophlebitis involved continued intravenous antibiotics and the addition of heparin. But an important randomized trial has shown absolutely no difference in time to cure or recurrence rates in patients who did or did not receive intravenous heparin. As a result, contemporary thinking is that continued broad-spectrum high-dose intravenous antibiotic therapy is all that's necessary in most patients with septic pelvic thrombophlebitis.
"I would reserve heparin for patients who have frighteningly large thrombi," he explained.
"Coumadin should only be used in the rare setting of the patient who has septic emboli. And surgery should be reserved for the patients with septic pelvic throm-bophlebitis with imaging study confirmation who are not getting better with antibiotics. In those cases the infected thrombus will need to be removed," Dr. Gibbs said.
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|Publication:||OB GYN News|
|Date:||May 1, 2002|
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