Simultaneous occurrence of Clostridium difficile and Cytomegalovirus colitis in a recipient of autologous stem cell transplantation.

Sir, Diarrhea is a major cause of morbidity among recipients of autologous bone marrow transplantation (BMT). The cause is often multifactorial. The use of antineoplastic agents, antibiotics, radiotherapy, alterations in diet and various pathogens have all been implicated. Here we describe a case in a recipient of autologous transplantation who developed life-threatening diarrhea from two different pathogens. A 59-year old male with anaplastic large cell lymphoma underwent an autologous stem cell transplant with BEAM conditioning in first partial remission. After experiencing a stormy post-transplant period with ICU admission due to sepsis and pneumonia he returned to the ward on day +20. (neutrophil engraftment occurred on day +13). Subsequently he developed profuse diarrhea. Abdominal X-ray and CT scan revealed gross bowel dilatation with thickening of the wall of the descending colon wall and thickening of several loops of the small bowel. Sigmoidoscopy revealed abnormal mucosa covered by pseudomembranes: no samples were taken for histologic examination. Clostridium difficile toxin was isolated and the patient was treated with oral metronidazole and vancomycin for 13 days. As there was no improvement he underwent a second sigmoidoscopy and a rectal biopsy. This demonstrated the typical viral inclusions consistent with CMV colitis (Figure 1). At the same time whole blood CMV PCR testing was found to be positive. He commenced a two-week course of ganciclovir that resulted in resolution of his diarrhea and conversion to CMV PCR negativity. Clostridium difficile is a major cause of nosocomial diarrhea. It accounts for almost all cases of pseudomembranous colitis and up to 20% of antibiotic-associated diarrhea. The severity and the prevalence of the infection in immunocompromised patients and especially in those who undergo BMT has not been fully evaluated. In a retrospective study by Bilgrami et al.1 in 200 autologous transplant recipients the incidence was 7%, with 14 patients experiencing 15 episodes at a median of 33 days after stem cell infusion. All patients responded to standard treatment and no fatalities were reported due to Clostridium difficile. CMV infection and disease remains a major problem following allogeneic BMT. Despite a similar incidence of infection, the incidence of CMV disease is extremely low in recipients of autologous transplantation. In a study by Wingard et al.2 the investigators reviewed the occurrence of CMV infection in 143 recipients of autologous transplants. Evidence of CMV infection was detected in 45% of patients but only 2% developed disease (pneumonitis) and died. CMV enteritis is a well recognized complication in immunocompromised patients.3-7 To our knowledge no documented cases have been previously reported in recipients of autologous transplantation. Another unusual feature of our case is the simultaneous occurrence of two pathogens with similar clinical manifestations creating diagnostic problems. In conclusion diarrhea is a common event in patients having received an autologous transplant. Despite the fact that many other causes are far more common, CMV colitis should be considered in the differential diagnosis. Concomitant infection with other pathogens such as Clostridium difficile may mask the diagnosis and we recommend that patients not responding to initial treatment should undergo sigmoidoscopy and biopsy.