S4115 Management of Gastrointestinal Spirochetosis

Introduction: Human intestinal spirochetosis (HIS) is a rare infection which is often identified on colonic biopsies. We present a series of patients with HIS in a single center to better understand the clinical significance and treatment of this condition. Case Description/Methods: We present the case of 4 patients who were diagnosed with human intestinal spirochetosis. All 4 patients are men, mean age 48.75 (range 21-86 years). Seventy-five percent of the patients are black and 25% White. Fifty percent of the patients were not immunocompromised, 25% were on immunosuppressive medications for multiple sclerosis, and 25% were immunocompromised with HIV. Seventy-five percent of patients reported chronic diarrhea, and 66% of these patients also reported hematochezia. Twenty-five percent of patients presented due to weight loss alone. In 100% of cases, the diagnosis of HIS was made by random colonic biopsies. Histopathologic examination demonstrated numerous spirochete organisms lining the surface of the colonic mucosa highlighted with the Warthin-Starry stain, and absence of active inflammation or microscopic colitis. 50% of cases had concomitant Helicobacter pylori infection. Seventy-five percent of patients were treated with metronidazole-based therapy for 10-14 days. Twenty-five percent were treated for Helicobacter pylori with omeprazole, clarithromycin, and amoxicillin for 14 days with resolution of symptoms. Following treatment, 100% of patients had an initial resolution of all symptoms, but 25% of patients had a recurrence of diarrheal symptoms 5 months after metronidazole-based therapy. No repeat colonoscopies have been required for these patients. Discussion: Patients with HIS may be asymptomatic or present with diarrhea, abdominal pain, and bloating. In some cases, HIS has been reported in immunocompromised and critically ill patients, but there does not appear to be a correlation between the degree of immunodeficiency and severity of symptoms. The patients in this case series treated with metronidazole had an initial resolution of symptoms, however other studies have shown symptom relapse despite antibiotic use. A recent study found a recurrence of symptoms after treatment with metronidazole due to spirochete translocation from the colonic surface to colonic crypts and residing in goblet cells. This may explain why HIS symptoms may recur after treatment. Further research on the rate of recurrence of this infection with various antibiotics is necessary to determine the most effective treatment approach for HIS.