What is the most appropriate management step for a patient with a history of recurrent perianal abscesses, presenting with a tender mass, redness, and a fistula with fluctuation in the perianal area, and normal abdominal examination?

Examination Under General Anesthesia (EUA) with Drainage

The most appropriate management is D - Examination under general anesthesia with immediate surgical drainage. This patient has a fluctuant perianal abscess with an associated fistula and recurrent disease history, which mandates urgent surgical intervention that cannot be adequately performed at the bedside 1.

Why EUA is Mandatory

• Fluctuation indicates a collection requiring immediate surgical drainage, which is the cornerstone of treatment for all perianal abscesses 1.
• EUA should not be postponed even if imaging is unavailable when a perianal abscess is clinically suspected, as recommended by the European Crohn's and Colitis Organisation 1.
• The timing should be within 24 hours for patients without sepsis, diabetes, immunosuppression, or diffuse cellulitis (which would require emergency drainage) 2, 1.
• Complete drainage is essential, as inadequate drainage is the primary risk factor for recurrence 2.

Why Other Options Are Inappropriate

CT Pelvis (Option A) - Incorrect

• Clinical diagnosis is sufficient for typical perianal abscesses 2.
• Do not delay drainage if imaging is not immediately available 1.
• Imaging is only considered for atypical presentations, suspected supralevator/intersphincteric abscesses, or suspected Crohn's disease 2.

Oral Antibiotics with Outpatient Follow-up (Option B) - Incorrect

• An undrained perianal abscess can expand into adjacent spaces and progress to generalized systemic infection 2.
• Antibiotics are not routinely indicated after adequate surgical drainage and are never a substitute for drainage 2, 3.
• Antibiotics only have a role when there is sepsis, significant cellulitis, or incomplete source control 2.

Bedside Needle Aspiration (Option C) - Incorrect

• Incision and drainage is the cornerstone of treatment, not needle aspiration 2, 1.
• The incision should be kept as close as possible to the anal verge to minimize potential fistula length while ensuring adequate drainage 2.
• Needle aspiration cannot provide the complete drainage necessary to prevent recurrence 2.

Critical Management Principles During EUA

• Do not actively probe for the fistula during acute abscess drainage to avoid creating iatrogenic tracts and complicating future management 1.
• If an obvious fistula is identified without probing, place a loose draining seton rather than performing fistulotomy 1.
• Never attempt fistulotomy during acute abscess drainage to minimize tissue disruption and preserve anal function 1.
• Use multiple counter incisions for large abscesses rather than a single long incision, which creates step-off deformity and delays healing 2.

Special Considerations for This Patient

• The history of recurrent presentations with spontaneous drainage strongly suggests underlying fistula-in-ano, which occurs in approximately one-third of perianal abscess cases 1.
• Exclude underlying Crohn's disease in every patient with recurrent anorectal abscess 1.
• Perform endoscopic evaluation of the rectum after the acute phase resolves to determine the most appropriate long-term management strategy 1.
• The patient should be counseled that definitive fistula management will require subsequent treatment planning after the acute sepsis resolves, potentially including sphincter-sparing procedures 1.

Post-Operative Management

• Antibiotics are not routinely needed after adequate surgical drainage unless sepsis or significant cellulitis is present 2, 1.
• Routine imaging after drainage is not required unless there is recurrence, suspected inflammatory bowel disease, or evidence of non-healing wound 1.
• The role of wound packing remains controversial, with some evidence suggesting it may be costly and painful without adding benefit 2.