What is the treatment for a peri-rectal abscess?

From the Guidelines

The treatment for a peri-rectal abscess typically involves surgical drainage as the primary intervention, which should be performed promptly to relieve pain and prevent complications, as recommended by the most recent guidelines 1, 2, 3.

Key Considerations

• The surgeon makes an incision over the abscess, drains the pus, and may leave the wound open to heal from the inside out.
• Antibiotics alone are generally insufficient for treatment but may be prescribed as adjunctive therapy, particularly for patients with systemic symptoms, immunosuppression, or extensive cellulitis, as suggested by recent studies 3.
• Common antibiotic choices include metronidazole 500mg three times daily plus ciprofloxacin 500mg twice daily for 7-10 days, or amoxicillin-clavulanate 875/125mg twice daily for 7-10 days.
• Pain management with acetaminophen or NSAIDs is important during recovery.
• Warm sitz baths (sitting in warm water) for 10-15 minutes several times daily can help with healing and comfort.

Post-Operative Care

• Patients should maintain good perianal hygiene and follow up with their healthcare provider to ensure proper healing and to check for fistula formation, which occurs in approximately 30-50% of cases.
• The role of wound packing after anorectal abscess drainage remains unproven, and its use should be left to individual unit policy and patient discussion, as stated in recent guidelines 2.

Special Considerations

• In patients with anorectal abscess and concomitant fistula, fistulotomy at the time of abscess drainage may be considered only in cases of low fistula not involving sphincter muscle, as recommended by recent guidelines 1.
• In patients with anorectal abscess and an obvious fistula involving any sphincter muscle, a loose draining seton may be placed, as suggested by recent studies 1.
• The timing of surgery should be based on the presence and severity of sepsis, and fit, immunocompetent patients with a small perianal abscess and without systemic signs of sepsis may be considered for outpatient management, as recommended by recent guidelines 1, 2.

From the FDA Drug Label

INTRA‑ABDOMINAL INFECTIONS, including peritonitis, intra‑abdominal abscess, and liver abscess, caused by Bacteroides species including the B. fragilis group (B. fragilis, B. distasonis, B. ovatus, B. thetaiotaomicron, B vulgatus), Clostridium species, Eubacterium species, Peptococcusniger, and Peptostreptococcus species. SKIN AND SKIN STRUCTURE INFECTIONS caused by Bacteroides species including the B. fragilis group, Clostridium species, Peptococcus niger, Peptostreptococcus species, and Fusobacterium species The treatment for a peri-rectal abscess may involve antibiotics and surgical procedures. Metronidazole tablets are indicated in the treatment of serious infections caused by susceptible anaerobic bacteria.

• Indicated surgical procedures should be performed in conjunction with metronidazole tablet therapy.
• In a mixed aerobic and anaerobic infection, antimicrobials appropriate for the treatment of the aerobic infection should be used in addition to metronidazole tablets 4.

From the Research

Treatment for Peri-Rectal Abscess

The treatment for a peri-rectal abscess typically involves incision and drainage (I&D) of the abscess, often in conjunction with antibiotics.

• The goal of I&D is to drain the abscess and reduce the bacterial load, while antibiotics are used to prevent further infection and promote healing 5, 6.
• A study published in 2020 found that inadequate antibiotic coverage after I&D of complicated peri-rectal abscess resulted in a six-fold increase in the re-admission rate 5.
• Another study from 1995 found that abscess resolution occurred in all patients after adequate drainage, and antibiotics appeared to be useful only as adjunct therapy 6.

Antibiotic Therapy

Antibiotic therapy is an important aspect of treating peri-rectal abscesses, particularly in cases where the abscess is complicated or there is a high risk of infection.

• A systematic review and meta-analysis published in 2019 found that antibiotic therapy following incision and drainage of anorectal abscesses was associated with a 36% lower odds of fistula formation 7.
• However, the use of antibiotics is not without controversy, and the choice of antibiotic and duration of treatment should be guided by the results of culture and sensitivity testing 8.
• A study from 2009 found that methicillin-resistant Staphylococcus aureus (MRSA) was a prevalent and underrecognized pathogen in perirectal abscesses, and that antibiotics coverage was often inadequate 8.

Risk Factors for Complications

Several risk factors have been identified for complications after treatment of peri-rectal abscesses, including:

• Preoperative sepsis, bleeding disorder, and non-Hispanic black and Hispanic races 9.
• Morbid obesity, preoperative sepsis, and dependent functional status 9.
• Female sex, steroid/immunosuppression, and dependent functional status 9.

Management Strategies

Effective management of peri-rectal abscesses involves early, adequate drainage, with antibiotics in an adjunct role 6.

• The use of imaging modalities and thorough examination under anesthesia may help to prevent inadequate drainage and improve patient outcomes 9.
• A standard oral protocol combining antibiotics covering typical gram-positive, gram-negative, and anaerobic organisms should provide adequate coverage after surgical drainage 5.