A Case of Syphilitic Proctitis Mimicking Inflammatory Bowel Disease

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Journal of General Internal Medicine



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LEARNING OBJECTIVE #1: Distinguish differential diagnoses with similar presentations and use appropriate tests to arrive at proper diagnosis LEARNING OBJECTIVE #2: Recognize laboratory data and correlate with scientific evidence and overall clinical picture to deliver appropriate treatment. CASE: Patient is a 36 year old male with history of unprotected anal intercourse with both men and women who presented with constipation and left lower quadrant abdominal pain for four days. Proctitis was noted on imaging. Patient has no known family medical history of inflammatory bowel disease. Patient was also noted to have leukocytosis, fever, and elevated ESR and CRP. Fecal calprotectin was negative. While awaiting culture results, given history, patient was empirically treated with Ceftriaxone and Doxycycline. Screening for HIV, Neisseria gonorrhoeae, Chlamydia trachomatis, stool culture, and stool ova/parasites were negative. Serology screening with rapid plasma reagin test for syphilis was also negative. Patient’s leukocytosis and fever resolved with antibiotics. Constipation also resolved with supportive treatment. However, patient reported painful defecation and we proceeded with colonoscopy. Distal proctitis, with two clean-based shallow ulcers, 8mm and 4mm respectively, was noted with otherwise unremarkable colonoscopy. Ulcer biopsy showed benign colonic mucosa with inflammatory changes, without evidence of IBD, dysplasia or malignancy. Immunoreactive tests for CMV and HSV were negative as well. Based on history, symptoms, and the characteristics of the ulcers, it was concluded that the rectal ulcers were sequelae of infectious etiology – most likely due to Syphilis and that the screening tests were likely false negative. Patient was given a one time dose of intramuscular Penicillin and was discharged to complete the 7 day course of Doxycycline. IMPACT/DISCUSSION: While patient’s initial presenting symptoms were suggestive of IBD, infectious etiology was more likely given history and acuity despite the negative screening tests. It is important to note that up to 20-30% of Syphilis patients can have nonreactive serology screening test. Furthermore, because syphilitic proctitis is more commonly associated with primary syphilis, it is possible that the acuity could have yielded a negative screening test. Moreover, syphilitic proctitis can present similarly to IBD. Colonoscopy, while warranted in this case, can have nonspecific findings. Therefore, making medical decisions based on overall clinical picture ensured that the patient received appropriate diagnosis and treatment. CONCLUSION: - Consider the overall clinical picture as laboratory data can sometimes be falsely positive or negative. - Appreciate differential diagnoses that can present similarly as well as the benefits and limitations of diagnostic tests. - Obtain sensitive but pertinent information in a respectful manner to aid in diagnosis and educate patients on preventative measures


Digestive System Diseases



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