Eosinophils in severe sepsis in northern australia: do the usual rules apply in the tropics?

Abstract

Objectives: Eosinophilia is rare in severe sepsis in temperate areas. We present a case of suspected severe sepsis with eosinophilia that proved fatal and was subsequently diagnosed as drug rash with eosinophilia and systemic symptoms. We aim to determine how common eosinophilia in severe sepsis is in the tropics, where there is a higher background rate of eosinophilia due to parasitic infection.

Design: Retrospective analysis of prospective cohort study.

Setting: Tertiary hospital in tropical northern Australia.

Patients: Prospectively recruited cohort including all patients at least 15 years old admitted to a 350-bed teaching hospital in northern Australia between May 6, 2007, and May 5, 2008, with community-onset severe sepsis.

Interventions: None.

Measurements and main results: Peripheral eosinophil counts on days 1 and 3 of admission and at the time of discharge were recorded for each patient. Eosinopenia was defined as less than 0.1×10 9/L and eosinophilia as greater than 0.6×10 9/L. The median eosinophil count on day 1 was 0.0 (interquartile range, 0.0-0.1; range, 0.0-0.7×10 9/L). Out of 245 patients, 243 patients (99.1%) had a normal or low eosinophil count at admission. Lower counts correlated with higher Acute Physiology and Chronic Health Evaluation II score and 28-day mortality (p=0.02 for both correlations). The median count rose during the course of admission to 0.2 (interquartile range, 0.1-0.4) at the time of discharge (p<0.001 compared with day 1 count). Patients with eosinophilia at discharge were more likely to be Indigneous or remote-dwelling than those without eosinophilia, suggesting an unmasking of preexisting eosinophilia as sepsis resolves.

Conclusions: Eosinophilia is rare in severe sepsis, even in the tropics. Patients with suspected severe sepsis and eosinophilia should have diagnoses other than sepsis excluded. One such diagnosis is drug rash with eosinophilia and systemic symptoms.