Simultaneous CMV Colitis, minimal change Disease, and tubulointerstitial nephritis in an immunocompetent Adult: A rare diagnostic Challenge

Introduction Cytomegalovirus (CMV) is classically associated with opportunistic infections in immunocompromised hosts. However, it can also cause significant morbidity in immunocompetent individuals, particularly under physiological stress. This case highlights an unusual presentation of CMV colitis coexisting with minimal change disease (MCD) and tubulointerstitial nephritis (TIN) in an immunocompetent adult. Case Presentation: A 39-year-old woman presented with progressive lower extremity weakness, diarrhea, substantial weight loss, and reduced urine output. Initial labs revealed anemia, hypoalbuminemia, acute kidney injury, and elevated inflammatory markers. Despite negative infectious workup, renal biopsy demonstrated MCD with TIN. Colonoscopy revealed ulcerations; histology with CMV-positive immunohistochemistry confirmed CMV colitis. The patient was treated initially with ganciclovir 350 mg twice daily, followed by valganciclovir 900 mg twice daily and supportive therapy, resulting in rapid clinical and laboratory improvement. Discussion This case demonstrates how CMV can affect immunocompetent individuals, mimicking inflammatory bowel disease and precipitating renal complications. Coexisting use of pennyroyal herbal tea may have contributed to nephrotoxicity. A multidisciplinary approach, including timely endoscopy and renal biopsy, was critical for diagnosis and management. Conclusion CMV colitis should be included in the differential diagnosis of chronic diarrhea in immunocompetent adults. Secondary forms of MCD and TIN should be considered in systemic inflammatory contexts.