Leukemoid reactions complicating colitis due to Clostridium difficile

Background: We sought to describe the characteristics of patients who had Clostridium difficile colitis complicated by leukemoid reactions (total leukocyte count greater than 35 × 10⁹/L) and to determine whether this complication is associated with higher morbidity or mortality than C difficile colitis without leukemoid reactions. Methods: We performed a retrospective case series analysis of patients with a positive fecal assay for C difficile toxin and a peak leukocyte count greater than 35 × 10 ⁹/L during 1998 and 1999. Twenty cases that met these criteria were compared with 65 randomly selected control patients (patients with a positive C difficile toxin and a peak leukocyte count less than 35 × 10 ⁹/L). Results: The mean peak leukocyte count was 52 ± 18.2 × 10⁹/L (± SD) in the case group and 14.9 ± 6.5 × 10⁹/L in the control group. Patients with a leukemoid reaction had a lower temperature, a lower serum albumin level, and a higher hematocrit value. Multivariable logistic regression showed respiratory tract infection and lower temperature to be independent predictors of a leukemoid reaction. There were 10 deaths (50%) in the leukemoid reaction group and 5 deaths (7.7%) in the control group. All seven patients with a peak leukocyte count greater than 50 × 10⁹/L died, compared with eight deaths (10.3%) among the remaining 78 patients whose peak leukocyte count was less than 50 × 10⁹/L. Conclusion: Patients with C difficile colitis and a leukocyte count greater than 35 × 10⁹/L have a poor prognosis with a much higher mortality rate than patients who have C difficile colitis without a leukemoid reaction.