Clinical and hematologic features do not reliably identify children with unsuspected meningococcal disease

Objective. To determine the frequency of unsuspected meningococcal disease (UMD) in young febrile children with meningococcal infections and evaluate whether clinical and laboratory parameters commonly used in the evaluation of fever can help identify children with UMD. Methods. We reviewed the records of children with meningococcal disease from 1985 to 1996 at four referral centers. Children who were evaluated as outpatients and then discharged to home, from whom Neisseria meningitidis was isolated from blood or cerebrospinal fluid cultures obtained during these outpatient visits, were considered to have UMD. We compared clinical and laboratory parameters between these children and 6414 febrile outpatients 3 to 36 months old with negative blood cultures enrolled in a separate study of occult bacteremia. Results. We identified 381 children with meningococcal disease, of whom 45 (12%) had UMD. Of the 45 with UMD, 37 (82%) were 3 to 36 months old. Compared with the 6414 culture-negative patients, these 37 patients with UMD were significantly younger (8.9 +/- 5.4 vs 14.2 +/- 8.1 months) and had significantly higher band counts (14.3 +/- 11.1 vs 7.3 +/- 7.5%). There were no significant differences, however, in temperature, white blood cell counts, and absolute neutrophil counts. Multivariate analysis identified young age and the band count as independent predictors of UMD. Conclusions. Children ultimately diagnosed with meningococcal disease have commonly been evaluated as outpatients and discharged to home before diagnosis. Of the hematologic parameters frequently used in the evaluation of fever, only the band count differs significantly between young febrile children with UMD and those with negative cultures. Because UMD is uncommon in young febrile pediatric outpatients, however, the predictive value of the band count is low. Thus, the complete blood count is not routinely helpful for the diagnosis of UMD.