Treatment of Rectal Abscess

Diagnosis and Assessment

A focused medical history and complete physical examination, including digital rectal examination, should be performed to diagnose a rectal abscess 3, 4
Check for undetected diabetes mellitus by measuring serum glucose, hemoglobin A1c, and urine ketones, as diabetes is a common comorbidity in patients with anorectal abscesses 3, 4
For patients with signs of systemic infection or sepsis, request complete blood count, serum creatinine, and inflammatory markers (C-reactive protein, procalcitonin) 3, 5

Imaging is not routinely required but should be considered in cases of atypical presentation 1
Imaging is not routinely required but should be considered in cases of suspected occult supralevator abscesses 1
Perianal Crohn's disease may require imaging 1, 3
Preferred imaging modalities include MRI, CT scan, or endosonography based on clinical scenario and available resources 3

Surgical approach with incision and drainage is the definitive treatment for all anorectal abscesses 2, 6
Timing of surgery should be based on the presence and severity of sepsis 2, 7
For deeper or more complex abscesses, more extensive drainage may be required, potentially with multiple counter incisions 8

If a low fistula not involving sphincter muscle (subcutaneous fistula) is identified, fistulotomy can be performed at the time of abscess drainage 4
For fistulas involving sphincter muscle, place a loose draining seton rather than performing immediate fistulotomy to prevent incontinence 4
Avoid probing to search for a fistula if one is not obvious, as this may cause iatrogenic complications 4, 6

Antibiotics are not routinely indicated for adequately drained anorectal abscesses in immunocompetent patients 9, 8
Antibiotic administration is recommended in the presence of sepsis 6
Antibiotic administration is recommended for immunocompromised patients 2
When indicated, empiric broad-spectrum antibiotic therapy should cover Gram-positive, Gram-negative, and anaerobic bacteria 8
Consider sampling of drained pus in high-risk patients or those with risk factors for multidrug-resistant organisms 9, 6

No definitive recommendation can be made regarding wound packing after drainage based on current evidence 5, 6