Botulinum toxin is used to treat pelvic floor tension myalgia; however, its safety profile is poorly understood. We report an ischiorectal fossa abscess after pelvic floor injections of botulinum toxin. Physicians need to be aware of this possible complication, consider alternate injection techniques and antiseptic preparation before injection.
Case Report
A 39-year-old immunocompetent gravida 1 para 1 with 2.5-year history of painful bladder syndrome and pelvic floor tension myalgia (PFTM) was treated for refractory pelvic pain. Treatments included a pain management specialist, pelvic floor physical therapy (PFPT), gabapentin, duloxetine, baclofen vaginal suppositories, oral narcotics, trigger point injections of marcaine and kenalog, and finally intramuscular botulinum toxin (BoNT).
Two weeks before presentation the patient developed increasing pelvic pain unrelieved with therapy or trigger point injections. Spasm of the obturator internus and pubococcygeus muscles was present. A spinal needle within a rigid guide was used to inject 100 units of BoNT (diluted in 10 mL sterile saline and dived into four 2.5 mL injections). Initially, her pain improved; however, 3 days later she presented to the emergency department with severe right buttock pain different in location and nature from her prior pelvic floor pain.
A tender firm 4 × 3 cm area was noted at the right gluteal fold. No palpable vaginal or rectal mass was appreciated. She was afebrile. Laboratories showed white blood cell count 14.4, H/H 11.5/33.8. Computerized tomographic (CT) scan of the pelvis demonstrated a right perianal 3.9 × 3.4 cm fluid collection with surrounding soft tissue stranding ( Figure 1 ) . The patient was admitted for serial examinations and broad spectrum antibiotics—ampicillin, gentamicin, and metronidazole. Her pain increased over the next 24 hours. Repeat examination demonstrated expansion to an 8 × 8 cm fluctuant mass filling the ischiorectal fossa ( Figure 2 ) . Erythema and induration were present on the right buttocks and vaginal sidewall. Incision and drainage were performed through a 2-cm incision made along the gluteal fold. Given the proximity of the abscess to the skin, CT-guided drainage was not necessary. Copious purulent discharge was drained. The space was then copiously irrigated and packed with 1-cm plain packing strips. She was transitioned to metronidazole and ciprofloxacin orally. Wound cultures grew Klebsiella, Escherichia coli , coagulase negative staphlococus, and nonhemolytic streptococcus; negative for anaerobes. The postoperative course was uncomplicated. The wound was repacked daily and healed over 6 weeks.
