P0813 - Perianal Fistulising Disease Masquerading as Crohn’s Disease: Most Unusual Etiology

Vishwesh Bharadiya, ¹, Shekhar Swaroop, MBBS, MD², Himanshu Narang, MBBS, MD², Umang Arora, MBBS, MD¹, David Mathew, MBBS, MD¹, Sandeep Mundhra, MBBS, MD², Raju Sharma, MBBS, MD¹, Govind Makharia, MBBS, MD, DM¹, Saurabh Kedia, MBBS, MD, DM², Vineet Ahuja, MBBS, MD, DM^1
1All India Institute of Medical Sciences, Delhi, Delhi, India; ²All India Institute of Medical Sciences, New Delhi, Delhi, India

Introduction: Chronic perianal fistulae pose a diagnostic and therapeutic challenge, especially in immunocompromised individuals. We report a case of perianal fistulising disease in an HIV-positive patient, which had a typical presentation mimicking Crohn’s disease and even received biologicals until the real etiology was unmasked.

Case Description/Methods: A 29-year-old male presented with non-healing perianal fistulae, persistent perianal pain, and pus discharge for two years. He also had progressive dysphagia for two months, weight loss, and worsening pancytopenia over a year. Treatment began in 2019 with antibiotics and seton placement. However, a rectourethral fistula developed requiring suprapubic cystostomy. The fistula persisted and in 2021, surgical repair and diversion colostomy were performed, but dehiscence occurred at the incision site. Referral to a gastroenterologist in May 2022 revealed aphthous ulcers in the colon and erosions in the terminal ileum on colonoscopy. Histopathology showed granulomatous inflammation with chronic active colitis and ileitis. Imaging further indicated an inflammatory etiology with symmetrical long-segment mural thickening in the sigmoid colon on MR enterography and a distal loopogram confirmed the presence of a perianal fistulous tract. He was diagnosed with perianal fistulizing CD and received infliximab which worsened his symptoms.
The patient then presented to our center with persistent perianal discharge and odynophagia. A history of high-risk sexual behavior ten years back prompted a retroviral disease workup which revealed HIV infection and syphilis co-infection. An upper GI endoscopy revealed a lower esophageal ulcer with non-specific granulation tissue on histopathology. A colonoscopy showed multiple fistulous openings in the rectum without any ulcers. Imaging showed axillary and mesenteric lymphadenopathy and a perianal abscess without any bowel thickening or enhancement. Antiretroviral therapy (ART) and benzathine penicillin were initiated, leading to improvement in symptoms and healing of the esophageal ulcer.

Discussion: This case highlights the importance of considering infectious etiologies like syphilis in immunocompromised patients with chronic perianal fistulae before diagnosing Crohn’s disease. Perianal fistulising disease is a rare manifestation of secondary syphilis, mimicking Crohn’s disease. A high index of suspicion with early consideration of high-risk behaviors in the patient's history is key to early diagnosis and treatment.



Disclosures:


Vishwesh Bharadiya, ¹, Shekhar Swaroop, MBBS, MD², Himanshu Narang, MBBS, MD², Umang Arora, MBBS, MD¹, David Mathew, MBBS, MD¹, Sandeep Mundhra, MBBS, MD², Raju Sharma, MBBS, MD¹, Govind Makharia, MBBS, MD, DM¹, Saurabh Kedia, MBBS, MD, DM², Vineet Ahuja, MBBS, MD, DM¹. P0813 - Perianal Fistulising Disease Masquerading as Crohn’s Disease: Most Unusual Etiology, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.