Hemolytic uremic syndrome associated with Clostridium difficile colitis

Abstract

Sirs, The most common cause of diarrheal hemolytic uremic syndrome (HUS) in children in North America is Escherichia coli type O 157 H 7 infection [1]. While there are some reports of other organisms being isolated from fecal samples of children with diarrheal HUS, such as viruses [2], salmonella [3], and campylobacter [4], a causal role for these agents in the pathogenesis of HUS has not been convincingly demonstrated. Serological studies in some children thought to have nonE. coli -related HUS have shown a specific immune response to the E. coli O 157 H 7 lipopolysaccharide, indicating a coinfection with the verotoxin-producing E. coli [5]. We recently encountered an 11-year-old child with Clostridium difficile colitis who developed HUS. This young man was admitted with a 5-day history of severe cramping abdominal pain, emesis, and bloody diarrhea. Within 2 days of admission, his hemoglobin and platelet counts dropped, he developed oliguric renal failure, and had evidence of shistocytes on his peripheral blood smear. There was no laboratory evidence of disseminated intravascular coagulation. A stool culture (using the sorbitol MacConkey agar for E. coli detection) on admission (5 days into his illness) was positive only for C. difficile, with no detection of E. coli O 157 H7. Due to this atypical finding, a renal biopsy was performed and confirmed the diagnosis of HUS. A subsequent stool test for shiga toxin (by ELISA) was negative. This child was managed conservatively with fluid restriction, the use of diuretics and anti-hypertensive medications, and was able to avoid dialysis. HUS has been previously reported in association with C. difficile colitis and pseudomembranous colitis [6]. However, in these children fecal samples were not evaluated for the presence of shiga-like toxin, which can be produced by non-O 157 H7 strains of E. coli and result in HUS. Although we did not evaluate our patient for the presence of antibodies to E. coli, the sensitivity of the combined stool studies for detecting HUS-causing E. coli (ELISA and culture) is reported to be very high [7], making E. coli an unlikely co-pathogen. We would definitely recommend adding C. difficile to the list of proven causes of diarrheal HUS in children, and suggest that testing for this pathogen be considered, at least in children with HUS and negative stool studies for E. coli.