Abstract
BACKGROUND: Cytomegalovirus (CMV) infections can cause significant morbidity and mortality in immunocompromised individuals. CMV targets dysfunctional lymphocytes. Chronic rituximab (RTX) therapy can cause B-lymphocyte dysfunction, increasing CMV risk. Rarely, CMV infections present with critical illness such as septic shock. CASE SUMMARY: A 64-year-old African American woman presented with generalized weakness and non-bloody watery diarrhea of 4-6 weeks duration. She did not have nausea, vomiting or, abdominal pain. She had been on monthly RTX infusions for neuromyelitis optica. She was admitted for septic shock due to pancolitis. Blood investigations suggested pancytopenia and serology detected significantly elevated CMV DNA. Valganciclovir treatment led to disease resolution. CONCLUSION: This case illustrates an extremely rare case of CMV colitis associated with RTX use presenting with septic shock. High suspicion for rare opportunistic infections is imperative in individuals with long-term RTX use.