[Is it necessary to perform a lumbar puncture in the evaluation of the febrile newborn infant without source?]

Lumbar puncture to detect bacterial meningitis is a recommended screening procedure to be performed in febrile newborn infants at admission to hospital.

To evaluate the usefulness of this procedure performed at admission and eventually, in a second look if clinically justified.

There were studied 1,841 febrile newborns consulting at the Emergency Department from January 1992 to December 2000 without source. All of them underwent a sepsis workup. The rate of meningitis incidence was calculated, and we analyzed the frequency of meningitis diagnosed in the initial evaluation and reappraisal.

There were 206 febrile patients with diagnosis of meningitis for an incidence of 11.2%, which 20 were bacterial (1.1%) and 186 aseptic meningitis (10.1%). In the initial evaluation 155 patients were diagnosed with meningitis (155/ 1.774 = 8.7%) and in reappraisal (mean 39,5 +/- 25,2 hours after) there were diagnosed another 51 cases (51/ 135 = 37.8%).

The meningitis was a common diagnosis in febrile newborns without source, with prevalence of aseptic meningitis. In almost 25% of cases we reached to this diagnosis by means of performing lumbar puncture after a reappraisal.