What is the treatment for a perirectal abscess?

Treatment of Perirectal Abscess

The definitive treatment for perirectal abscess is surgical incision and drainage, which should be performed promptly to prevent expansion of the abscess and progression to systemic infection. 1

Diagnosis

• Perirectal abscess typically presents with pain as the most common symptom (98.9% of cases), along with swelling, cellulitis, and tenderness in the perianal region 2
• Diagnosis is usually based on patient history and physical examination, including digital rectal examination, which identifies an abscess in 94.6% of patients 2, 1
• Imaging studies (CT, MRI, or endosonography) are not routinely required but should be considered in cases with atypical presentation, suspected deep supralevator abscesses, or in patients with suspected inflammatory bowel disease 1, 3

Surgical Management

• Incision and drainage is the cornerstone of treatment for all perirectal abscesses 1, 3
• The timing of surgery should be based on the presence and severity of sepsis 1, 3
• The incision should be kept as close as possible to the anal verge to minimize the length of a potential fistula while ensuring adequate drainage 1
• For larger abscesses, multiple counter incisions are preferred over a single long incision to prevent delayed wound healing 1
• During the procedure, examination should be performed to identify any associated fistula tract 3
• If a low fistula not involving sphincter muscle is identified, fistulotomy can be performed at the time of abscess drainage 3, 4
• For fistulas involving sphincter muscle, a loose draining seton should be placed rather than performing immediate fistulotomy to prevent incontinence 3

Antibiotic Therapy

• Antibiotics are not routinely indicated after adequate surgical drainage in immunocompetent patients 1, 3, 2

• Antibiotic therapy is recommended in the following situations:

  • Presence of systemic signs of infection or sepsis 1, 3
  • Immunocompromised patients 1, 3
  • Incomplete source control 1, 3
  • Significant surrounding cellulitis 1, 3

• When indicated, empiric broad-spectrum antibiotic therapy should cover Gram-positive, Gram-negative, and anaerobic bacteria 1, 5

• Recent evidence suggests that inadequate antibiotic coverage after incision and drainage of complicated perirectal abscess can result in a six-fold increase in readmission rates 5

Setting for Drainage Procedure

• The most recent evidence indicates that emergency department bedside drainage is equivalent to operative drainage in the operating room for adequately treating perirectal abscesses and preventing short-term complications 6
• Fit, immunocompetent patients with small perianal abscesses and without systemic signs of sepsis may be managed in an outpatient setting 1
• Deeper or more complex abscesses may require more extensive drainage in an operating room setting 3

Risk Factors for Complications

• Risk factors for prolonged hospitalization include preoperative sepsis, bleeding disorders, and certain racial backgrounds 7
• Risk factors for reoperation include morbid obesity, preoperative sepsis, and dependent functional status 7
• Risk factors for readmission include female sex, steroid/immunosuppression use, and dependent functional status 7

Follow-up Care

• Close follow-up is essential to monitor for recurrence or fistula development 8
• The recurrence rate after drainage can be as high as 44%, with risk factors including inadequate drainage, loculations, horseshoe-type abscess, and delayed time from disease onset to incision 1
• Routine imaging after incision and drainage is usually not required unless there is recurrence, suspected inflammatory bowel disease, or evidence of a fistula/non-healing wound 1