Inaccurate diagnosis in infants with pertussis. An eight-year experience.

A review was conducted of all patients seen at Upstate Medical Center, Syracuse, NY, from June 1975, to June 1983, whose nasopharyngeal specimens were positive by specific Bordetella pertussis-fluorescent antibody stain. Sixty-one patients were identified; 46 were hospitalized and 15 were outpatients. The age and immunization status of the two groups were compared. Admission diagnosis, indices of illness severity, and clinical course were assessed for the hospitalized patients. Review of the house officers' initial differential diagnoses disclosed that pertussis was considered in the diagnosis in only 45% of the cases. Bronchiolitis was the next most commonly listed diagnosis. Frequent vomiting and severe coughing were the most helpful clinical findings leading to an accurate diagnosis. Abnormal chest roentgenograms and elevated white blood cell counts were present in a minority of our patients, whether the initial diagnosis was correct or not. Younger and less-immunized patients had more severe and prolonged clinical courses. This study demonstrates that the diagnosis of pertussis is often missed or delayed because clinical findings are similar to those of other respiratory infections in infancy. Suspicion of the diagnosis in children with nonspecific respiratory illness is required for early diagnosis, treatment, and prevention of spread to susceptible individuals.