S1749 Human Intestinal Spirochetosis: An Atypical Cause of Symptomatic Colonic Ulceration

Abstract

INTRODUCTION: This case demonstrates an atypical presentation of intestinal spirochetosis in a patient with HIV on anti-retroviral therapy with adequate viral suppression. CASE DESCRIPTION/METHODS: A 56-year-old male presented with one day of hematochezia and abdominal cramping. He had a past medical history of HIV on Highly Active Antiretroviral Therapy with recent undetectable viral load and CD4 count of 1225. On initial assessment, he was tachycardic with frank blood on rectal examination. Hemoglobin was 11.8 with a baseline of 14.7. Computed Tomography scan of the abdomen and pelvis was significant for contrast extravasation in the cecum consistent with active gastrointestinal bleed. His hemoglobin further downtrended to 9.4, but he remained hemodynamically stable. Colonoscopy revealed a solitary twenty mm ulcer in the cecum without active bleeding. Biopsy obtained from the ulcer edge demonstrated intestinal spirochetosis (Warthin-Starry stain positive) and focal acute colitis with lamina propria hemorrhage. Patient remained clinically stable without further episodes of hematochezia and was discharged before biopsies resulted. Unfortunately, he was lost to follow-up. DISCUSSION: Human intestinal spirochetosis is rare in developed countries but when present, they are often found in homosexual males and those with HIV. Stool colonization rates in homosexual men in the US have ranged between 20.6 and 62.5%. It is most commonly caused by Brachyspira aalborgi or Brachyspira pilosicoli. Patients are often asymptomatic but can present with abdominal pain and watery diarrhea. Endoscopic findings are usually non-specific since mucosa may be normal, polypoid, or mildly erythematous. There are only case reports of colonic ulceration. Diagnosis is made by histology with hematoxylin-eosin and Warthin-Starry silver stains which demonstrate spirochetal adhesion along the border of the intercryptal epithelial layer. Treatment is reserved for immunocompromised and symptomatic patients and consists of metronidazole for 10 days with resolution of symptoms. Complete mucosal healing has been observed for those who opt for repeat endoscopy. Our patient is unique since he had sudden large-volume hematochezia without diarrhea and a rather discrete endoscopic finding despite viral suppression and a robust CD4 count. Therefore, clinical suspicion for intestinal spirochetosis should be moderately high in patients with these specific risk factors.Figure 1.: Clean-based cecal ulcer.Figure 2.: Warthin-Starry silver stain of cecal ulcer edge biopsy highlighting spirochetes on the surface epithelium.