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

Objectives: Eosinophiliais rare in severe sepsis in temperate areas. We present a case of suspectedsevere sepsis with eosinophilia that proved fatal and was subsequently diagnosedas drug rash with eosinophilia and systemic symptoms. We aim to determine howcommon eosinophilia in severe sepsis is in the tropics, where there is a higherbackground rate of eosinophilia due to parasitic infection.

Design: Retrospectiveanalysis of prospective cohort study.

Setting: Tertiaryhospital in tropical northern Australia.

Patients: Prospectivelyrecruited cohort including all patients at least 15 years old admitted to a350-bed teaching hospital in northern Australia between May 6, 2007, and May 5,2008, with community-onset severe sepsis.

Interventions: None.

Measurements andMain Results: Peripheral eosinophil counts on days 1 and 3 ofadmission and at the time of discharge were recorded for each patient.Eosinopenia was defined as less than 0.1 × 109/L and eosinophilia as greaterthan 0.6 × 109/L. The median eosinophil count on day 1 was 0.0 (interquartilerange, 0.0–0.1; range, 0.0–0.7 × 109/L). Out of 245 patients, 243 patients(99.1%) had a normal or low eosinophil count at admission. Lower countscorrelated with higher Acute Physiology and Chronic Health Evaluation II scoreand 28-day mortality (p = 0.02 for both correlations). The median countrose during the course of admission to 0.2 (interquartile range, 0.1–0.4) atthe time of discharge (p < 0.001 compared with day 1 count). Patientswith eosinophilia at discharge were more likely to be Indigneous orremote-dwelling than those without eosinophilia, suggesting an unmasking ofpreexisting eosinophilia as sepsis resolves.

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