Reactivated cytomegalovirus proctitis in an immunocompetent patient presenting as nosocomial diarrhea: a case report and literature review

BACKGROUND Reactivated cytomegalovirus (CMV) infection has been known to cause significant morbidity and mortality in immunocompromised patients. However, CMV disease rarely develops in immunocompetent patients, and reported cases often present with a mild, self-limiting course, without severe life-threatening sequelae. While the colon is the most common gastrointestinal site affected by CMV disease in immunocompetent patients, rectal involvement is rarely reported. CMV proctitis can present in two distinct forms, primary and reactivated. However, reactivated CMV proctitis is rarely reported as a causative etiology of nosocomial diarrhea, except in transplant patients. Herein we present a case of reactivated CMV proctitis in an immunocompetent patient, presenting as nosocomial diarrhea. Previously reported cases of reactivated CMV proctitis in immunocompetent patients are also reviewed. CASE PRESENTATION A 79-year-old female was admitted because of metabolic encephalopathy caused by dehydration and hypernatremia. The patient's consciousness level returned rapidly after fluid supplementation. However, she subsequently presented with abdominal pain and diarrhea on day 8 of admission. Abdominal contrast-enhanced computed tomography on day 10 of admission demonstrated inflammation around the rectum, suggesting proctitis. Colonoscopy on day 16 of admission showed a giant ulcer at the rectum. Pathology of rectal biopsy confirmed CMV infection. The patient recovered without sequelae after 38 days of valganciclovir treatment. Follow-up colonoscopy revealed a healed ulcer over the rectum. Ten cases in the literature, plus our case, with reactivated CMV proctitis in immunocompetent patients were reviewed. We found that most patients were elderly (mean, 72 years) with a high prevalence of diabetes mellitus (54.5%). Cardinal manifestations are often non-specific (diarrhea, hematochezia, tenesmus), and eight (72.7%) developed CMV proctitis following a preceding acute, life-threatening disease, rather than as an initial presentation on admission. These manifestations frequently develop during hospitalization, and are thus often regarded as nosocomial diarrhea. CONCLUSIONS Clinicians should be aware of the possibility of nosocomial onset of reactivated CMV proctitis in patients hospitalized due to a preceding critical illness, although the benefits of antiviral therapy remain unclear.