The Role of Hyperleukocytosis in Predicting the Severity of Pertussis

Abstract Background: Few reports have described the relationship between WBC count and the severity of pertussis or the timing of ET in patients with hyperleukocytosis.Methods: A retrospective clinical analysis of infants with pertussis and a WBC exceeding 30*10^9/L was performed.Results: A total of 158 patients were enrolled in the study. There were significant differences in the clinical manifestations of cyanosis, fever, highest respiratory rate, and highest heart rate. There were significant differences in all complications except for pulmonary hypertension. In laboratory findings, there were significant differences in organ damage (myocardial markers, ALT), increased inflammation indicators (CRP, PCT), and the incidence of combined bacterial infections. There were significant differences in ICU stay length, mechanical ventilation use, days hospitalized, days until cough relief and days until the WBC fell below 25*10^9/L. A WBC count >55.38 *10^9/L was calculated as the cutoff value with 88.2% sensitivity and 23.4% specificity in predicting ET. A respiratory rate of 59 breaths/min had 94.1% sensitivity and 36.7% specificity in predicting ET. A heart rate of 159 beats/min had 100% sensitivity and 38.1% specificity in predicting ET.Conclusion: WBC count is related to the severity of pertussis. We recommend that ET is considered when the patient’s WBC count exceeds 55*10^9/L, breathing exceeds 60 breaths/min, and/or heart rate exceeds 160 beats/min.