Protean Proctidites: The Diagnostic Challenges of Rectal Chlamydia-A Case Series

Introduction: Chlamydia trachomatis (C. trachomatis) is a common sexually transmitted bacterial infection with rising incidence. Diagnosis can be challenging as the infection is often asymptomatic. Additionally, lack of awareness of the condition can contribute to missed diagnosis in patients with proctitis symptoms. We present a case series of 2 patients with rectal chlamydia highlighting their distinct clinical presentations and diagnostic challenges. Case Description/Methods: Case 1: A 33 year-old man with human immunodeficiency virus (HIV) on antiviral therapy presented with rectal pain and bleeding for 2 months with multiple emergency room visits and a surgical evaluation. Unable to tolerate an anoscopy due to pain, he received therapy for a possible anal fissure. Labs showed a normocytic anemia and an undetectable HIV viral load. Computed tomography (CT) of the abdomen showed rectal and distal sigmoid thickening. Colonoscopy showed a 5 cm rectal ulcer and ulcerations in the anal canal and biopsies demonstrated active inflammation. A rectal swab was positive for C. trachomatis. The patient was prescribed a 21 day course of doxycycline and his rectal pain and bleeding quickly improved. Case 2: 55 year old man with history of gastric adenocarcinoma had anterior rectal wall thickening noted on routine CT surveillance. He was asymptomatic. Flexible sigmoidoscopy showed erythema in the rectal wall with a single small ulcer. Biopsy showed reactive inflammatory changes. Following the procedure he noted episodes of hematochezia and endorsed receptive anal intercourse prompting testing with rectal swab which confirmed C. trachomatis. He was treated with doxycycline. Discussion: Individuals at risk of rectal C. trachomatis are often not screened in extragenital sites, possibly due to lack of awareness, which leads to higher disease incidence. Patients’ presentations can vary, and symptoms can mimic other processes like NSAID use, solidary ulcer syndrome, or malignancy. Doxycyline is the preferred treatment due to azithromycin having treatment failure rates as high as 22% due to low rectal penetration and antimicrobial resistance. Giving the rising prevalence, it is imperative that the diagnosis of rectal chlamydia be considered in sexually active patients or patients with proctitis symptoms. Routine screening should be considered to help identify asymptomatic infections early and to combat the spread of this disease.