A Rare Case of Cytomegalovirus Colitis in an Immunocompetent Patient Mimicking Clostridium difficile Colitis

Abstract

Cytomegalovirus (CMV) colitis usually occurs in immunocompromised patients and can cause significant morbidity and mortality. We report a 68 year old immunocompetent male presenting with abdominal pain and diarrhea who was found to have CMV colitis. 68 year old african american male with a history of end stage renal disease on hemodialysis presented with a one month history of watery diarrhea, diffuse abdominal pain, and weakness. Patient reported a 15-lb weight loss. No blood or mucus seen in the stool. He denied nausea or vomiting, dietary changes, international travel, sick contacts, or recent antibiotic use. Physical examination revealed tachycardia, dry mucous membranes, and a normal abdominal exam. Laboratory data was only remarkable for electrolyte abnormalities: sodium 150 mg/dL, potassium 2.1 mg/dL, and phosphorus 1.1 mg/dL. The patient received intravenous fluids and his electrolytes were corrected. CBC, TSH, urinary 5-HIAA, and celiac panel were normal. Fecal leukocytes, clostridium difficile toxin PCR, rotavirus ELISA, bacterial cultures, giardia, and cryptosporidium antigen were negative. An abdominal computed tomography was concerning for an infectious or inflammatory colitis in the descending and sigmoid colon. ESR, CRP, and fecal calprotectin were elevated. Patient underwent a colonoscopy with biopsies, which revealed diffuse viability with ulcers, exudates and pseudomembranes concerning for clostridium difficile (CD) colitis. Patient was started on oral vancomycin. Despite treatment, his diarrhea did not improve. Later, colonic biopsies surprisingly revealed cytopathic evidence consistent with CMV colitis ( Figure 1 & 2). CMV viral load was elevated at 2592 copies/mL. Human immunodeficiency virus serology was negative. Vancomycin was stopped, and the patient was started on ganciclovir with resolution of diarrhea.1554_A Figure 1. Left image: the arrows indicate CMV “owl's eye inclusions on H & E ( 40x) Right image: corresponding CMV infected cells light up brown with IHC (immunohistochemistry) stain. (40x)1554_B Figure 2. Left Image: the arrows indicate CMV “owl's eye inclusions on H & E ( 20 x) Right Image: corresponding CMV infected cells light up brown with IHC (immunohistochemistry) stain. ( 20 x)CMV colitis rarely occurs in immunocompetent patients making it a diagnostic challenge. Furthermore, it can mimic CD colitis because of some similar overlapping endoscopic findings. Recognizing that CMV colitis may occur in immunocompetent patients can prevent serious morbidity and mortality, especially in those with advanced age and multiple medical comorbidities.