Predicting pertussis in a pediatric emergency department population.

Cases of pertussis, a potentially life-threatening illness in infants younger than 6 months of age, are at a 40-year high. Children frequently present to emergency departments for initial evaluation. Quick recognition of the illness allows rapid triage, isolation, and prevention of nosocomial transmission. A retrospective, case-control chart review was conducted of pediatric emergency department patients (0 to 18 years of age) presenting between January 1, 2003, and December 31, 2004. Analysis focused on the exploration of medical history and physical examination variables as predictors using laboratory verification of the presence of pertussis as a binary outcome variable. Infants younger than 2 months who have a cough or choking associated with cyanosis, as well as a cough and rhonchi on physical examination, have a high likelihood of pertussis and should be identified in triage, isolated immediately, and tested for pertussis. This may lead to appropriate therapy for this population and decrease the transmission of pertussis to other patients and staff in the pediatric emergency department.