Pelvic abscess associated with vaginal delivery is a rare finding. Abscess formation more than 1 month after vaginal delivery is very uncommon. To our knowledge there has been only 1 report of delayed presentation of pelvic abscess 1 month after vaginal delivery.¹ This is the second case of a young woman with a pelvic abscess occurring 30 days post–vaginal delivery.

Case Presentation
A 30-year-old woman presented to the emergency department complaining of fever, chills, and diarrhea. She said she had had vaginal delivery with median episiotomy 30 days ago, and she was tolerating food well until 3 days ago. Her medical history was significant for essential hypertension, a femoral fracture that had been treated with an intramedullary nail, and a cesarean section (for her first delivery). She was taking a daily antihypertensive—amlodipine besylate (Norvasc, Amvaz).

She was admitted to the hospital. Her vital signs at admission were: temperature, 104°F; pulse, 112 beats/min; blood pressure, 131/70 mm Hg. Her white blood cell count was 37.7 x 10⁹/L. Physical examination showed feculent material in the vagina and a healing episiotomy incision. Fourth-degree perineal tears secondary to her vaginal delivery appeared to be well healed at the time of this current presentation. She had a small rectovaginal fistula, which was being treated conservatively.

The patient was hydrated with intravenous fluids and was started on broad-spectrum antibiotics empirically. Computed tomography (CT) scan of the abdomen and the pelvis showed a large, multiloculated pelvic abscess (Figure). The abscess was complex and septated, measuring 12 x 6 cm (craniocaudal length, 7 cm). It extended along the right pelvic sidewall, with its posterior aspect positioned between the cervix and rectum.

The abscess caused rectosigmoid displacement to the contralateral side. Air was evident in the cervix and vagina. All other structures were normal. Blood cultures were positive for viridans group streptococci. Abscess cultures showed Streptococcus intermedius. Antibiotic coverage was adjusted, and the patient then had CT-guided drainage of the abscess. Catheters were left in place for residual drainage. The patient defervesced and was discharged. Follow-up colonoscopy was normal.

Discussion
The proposed etiology of abscess formation after vaginal delivery is laceration of the vaginal wall during the delivery, which then exposes otherwise sterile compartments to the native bacterial flora of the vagina. A study of surveillance data from medical records of 2746 women who received postpartum care at one institution showed an overall 5.5% infection rate after vaginal delivery.² More important, 94% of all postpartum infections were detected after hospital discharge, and 74% of the patients were treated for the infection in hospitals other than where they delivered.² 

Most women with postpartum infection will present with mastitis, urinary tract infections, and episiotomy- site infections.² Although rare, delayed presentation of pelvic abscess must be considered in women who present with fever, chills, and gastrointestinal symptoms more than 1 month postpartum.

Postpartum adrenal, liver, retroperitoneal, and splenic abscesses have all been reported.^3-6 Such abscesses have all occurred less than 1 month postpartum; our patient, however, presented with an abdominopelvic abscess at 1 month postpartum.

The appearance of the abscess on the CT scan implicates the bowel as a possible source. The abscess is clearly displacing the rectosigmoid colon, and part of the multiloculated mass is between the cervix and the bowel. In addition, a fourth-degree perineal laceration has entered the lumen of the colon; however, lack of anaerobes in the culture is perplexing and contradicts this analysis.

Microperforation of the uterine scar during vaginal birth that was preceded by a previous delivery by caesarean section has been reported, if rarely,⁷ but in such a situation, air would be present in the peritoneal cavity. Microperforation of an old scar is a very painful event and is sometimes masked by epidural anesthesia. Finally, the performance of episiotomy at the time of vaginal delivery provides the vagina as a source for the pelvic abscess.^8,9

In one study, 30% (147 of 482) of the pregnant women had positive cultures for viridans group streptococci, and of these, S intermedius was responsible for 13% of the positive cultures.¹⁰ 

The abscess culture of our patient revealed S intermedius as a sole isolate. We determined that the most probable source of this patient’s abscess was the genital tract. This is consistent with a randomized, controlled trial that showed that restriction of episiotomy in multiparous women in this study resulted in significantly fewer perineal tears. Furthermore, all third- and fourth-degree perineal tears in multiparous women in this study were associated with the use of median episiotomy.¹¹

A minimally invasive approach (ie, CT-guided drainage) for this patient was successful. At 30 days of follow-up, the patient remained asymptomatic.

Conclusion
Although the classic teaching regarding the timing of presentation of a pelvic abscess after vaginal delivery is 5 to 10 days, delayed presentation can occur later than this time frame, as our case clearly demonstrates.  

References
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2. Yokoe DS, Christiansen CL, Johnson R, et al. Epidemiology of and surveillance for postpartum infections. Emerg Infect Dis. 2001;7:837-841.

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11. Klein MC, Gauthier RJ, Jorgensen SH, et al. Does episiotomy prevent perineal trauma and pelvic floor relaxation? Online J Curr Clin Trials [serial online]. July 1, 1992;doc 10.