Bulging Fontanelle in Febrile Infants as a Clinical Predictor of Bacterial Meningitis

Background: It is a common practice to perform a lumbar puncture in infants presenting with fever and a bulging fontanelle, in order to rule out bacterial meningitis; however, most of these infants have benign and self limited diseases.

Methods: We performed a retrospective cohort study of febrile children with a bulging fontanelle who underwent lumbar puncture at the Meir Medical Center between the years 2005-2015. χ² test and descriptive statistics were used for data analysis.

Results: 764 children aged 2-18 months underwent a lumbar puncture in the Meir Pediatric Department during the study period. A total of 10 infants were diagnosed with bacterial meningitis. Only one infant (10%) presented with a bulging fontanelle.

304 patients had a bulging fontanelle and fever on their evaluation. Amongst them cerebrospinal fluid pleocytosis was found in 115 cases (37.8%), including one case of bacterial meningitis (0.3%). None of the infants described on admissions as appearing either well or moderate on presentation were found to have bacterial meningitis.

The leading diagnoses for bulging fontanelle in febrile infants in our study were upper respiratory tract infections, aseptic meningitis and acute otitis media.

Conclusions: The finding of a bulging fontanelle, particularly if it’s the only relevant sign in the infant’s examination, has a very low sensitivity and specificity for bacterial meningitis. Most of the causes for a bulging fontanelle in febrile infants are self limited diseases. The routine approach of performing a lumbar puncture in febrile infants with a bulging fontanelle should be reconsidered.