Perianal secretion

Specialty: Gastrointestinal.

• Purulent or serous anal drainage
• active perianal fistula
• anal suppuration

Why it occurs

• Complex perianal fistula secondary to a previous poorly drained or unresolved anorectal abscess (cryptoglandular origin)
• Perianal fistulizing Crohn's disease (recurrent complex perianal fistulas due to transmural inflammation)
• Chronic perianal hidradenitis suppurativa with involvement of local apocrine glands
• Infected pilonidal cyst with fistulous tract branching towards the anal perineal region
• Sexually transmitted infections (gonocytosis, chlamydiasis, lymphogranuloma venereum, primary rectal syphilis) with suppurative proctitis.

Initial workup

Anal inspection under anesthesia or careful proctological examination with blunt stylet and anoscopy to map the internal and external os | 360-degree high-resolution endoanal ultrasound (to characterize the relationship with the sphincters) | Magnetic resonance imaging of the pelvis with fistula protocol (non-invasive study of choice to define supra- and trans-sphincteric tracts) | Serology for STIs, specific microbiological cultures, and fistula edge biopsy if Crohn's disease or malignancy is suspected.

Standard management

• Empirical antibiotic therapy directed at anaerobic and gram-negative flora — ciprofloxacin 500 mg every 12 hours combined with metronidazole 500 mg every 8 hours orally for 10-14 days
• Immunomodulators or biological anti-TNF therapy in fistulizing Crohn's disease — infliximab 5 mg/kg IV in induction and maintenance scheme
• Non-opioid oral analgesics — paracetamol 1 g every 8 hours or metamizole 575 mg every 8 hours to prevent opioid-induced constipation
• Sitz baths with lukewarm water without antiseptic additives (to promote continuous drainage and relax the sphincter).