Snapshot A 27-year-old female presents to the hospital with a 4-day history of fever and lower right quadrant abdominal pain. Three weeks ago she underwent an emergency cesarean for an active phase arrest. Her temperature is 102.8°F (39.3°C). A tender fluctuant mass is palpated in the lower right quadrant of her abdomen. A pelvic CT scan confirms the diagnosis. She is admitted to the hospital and started on intravenous antibiotics and percutaneous drainage. Introduction Overview a pelvic abscess is an inflammatory collection of purulent material that forms secondary to an infection within the pelvis it is a rare complication of pelvic infections (e.g., pelvic inflammatory disease (PID), endometritis) or pelvic surgeries (e.g., ceserean section) treatment is broad spectrum antibiotics and possible drainage Epidemiology Incidence rare, occurs in < 1% of pelvic surgeries or infections Demographic occurs several weeks-months following surgery or infection Risk factors history of PID most common etiology for pelvic abscess prior pelvic surgery bacterial vaginosis postoperative hematoma Etiology Pathogenesis mechanism ascension of bacteria from the lower genital tract, extension of an existing infection in the pelvis, or seeding of new infection from surgery Usually polymicrobial with predominance of anearobic bacteria (e.g., Bacteroides and Peptostreptococcus spp.) Presentation Symptoms lower abdominal pain malaise chills Physical exam fever abdominal tenderness in lower quadrants fluctuant pelvic, vaginal, or adnexal mass tachycardia tachypnea hypotension in severe or ruptured abscesses Imaging Computed tomography (CT) of pelvis indication imaging study of choice for the evaluation of pelvic abscess findings pelvic mass and low-attenuation centrally and ring enhancement with contrast Ultrasonography indication alternative study for the evaluation of pelvic abscess findings anechoic or hypoechoic pocket, possibly multiloculated Studies Serum labs leukocytosis elevated C-reactive protein (CRP) elevated erythrocyte sedimentation rate (ESR) Differential Septic pelvic thrombophlebitis key distinguishing features will present with persistent fever that does not respond to antibiotics and no evidence of an abscess on imaging Appendicitis key distinguishing features will present with migratory abdominal pain, McBurney point tenderness, Rovsing sign, psoas sign, or obturator sign Pyelonephritis key distinguishing features will present with flank pain, costovertebral angle (CVA) tenderness, and pyuria Treatment Management approach pelvic abscesses are managed conservatively when possible with intravenous antibiotics covering both aerobic and anaerobic bacteria percutaneous drainage and laparotomy are only used in select cases Medical intravenous broad spectrum antibiotics indications first line treatment modalities piperacillin-tazobactam ceftriaxone with either clindamycin or metronidazole Surgical percutaneous drainage indications large abscesses (> 7 cm) no response to antibiotic therapy within 72 hours laparotomy indications suspected ruptured abscess hemodynamic instability no response to medical therapy or percutaneous drainage Complications Ruptured abscess surgical emergency Prognosis > 70% of cases respond to intravenous antibiotics alone