S2681 A Pain in the Rectum: Syphilis Manifesting as Proctitis

Abstract

Introduction: Anorectal syphilis is often challenging to diagnose due to the atypical clinical presentation and asymptomatic disease course. Patients who engage in high-risk sexual behavior are at increased risk for sexually transmitted infections. We present a unique case of rectal bleeding and diarrhea secondary to anorectal syphilis. Case Description/Methods: A 31-year-old uninsured man presented to the ER with a 1 month history of rectal bleeding, abdominal pain and diarrhea. His past medical history is remarkable for untreated HIV and Factor V Leiden deficiency. He reported being sexually active with multiple male partners and engaging in unprotected anal receptive intercourse. He denied alcohol, tobacco or ilicit drug use. Vital signs were unremarkable on admission. Physical exam was significant for a soft abdomen with palpable tenderness in the lower quadrants without guarding or rebound tenderness. Digital rectal exam was negative for blood, stool, visible lesions or ulcerations. Labratory analysis revealed a hemoglobin of 15.2 g/dL and HIV CD4 count was 877 per mcL. Chemistry panel including liver tests were within normal limits. Computed tomography (CT) of the abdomen revealed mucosal thickening of the rectum with mild fat stranding consistent with inflammation. In the setting of reported hematochezia and abnormal imaging findings the patient underwent colonoscopy which revealed multiple, shallow ulcerations confined to the rectum. Ulcer biopsies were obtained and revealed active proctitis with spirochetes on immunostaining. Treated was initiated with Penicillin G. He had improvement in abdominal pain and resolution of hematochezia. (Figure) Discussion: Syphilitic proctitis is most often associated with pain on defecation, intermittent rectal bleeding and diarrhea. In high risk patient groups, such as MSM and sex workers, clinical suspicion should be high for sexually transmitted infections that affect the anorectal region. Diagnosis of syphilis is based on clinical findings, serological testing and in some cases, tissue biopsy. Primary disease usually occurs at the exterior anal verge, at points of sexual contact. Our case describes syphylitic ulcerations scattered within the rectum without exterior involvement, making it a highly unusual presentation. Although various diagnostic information can be helpful, it is vitally important that physicians rely on their own expertise and knowledge to recognize subtle findings that may help establish a diagnosis, especially in those who are immunocompromised.Figure 1.: Multiple scattered ulcerations in the rectum (white arrows).