Pragmatic and evidence-based approach to paediatric cerebrospinal fluid reference limits for white cell count and concentrations of total protein and glucose

Bulging fontanelle in febrile infants as a predictor of bacterial meningitis

It is 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, self-limiting diseases. The objective was to determine whether there is an association between bulging fontanelle and bacterial meningitis in febrile infants. This retrospective cohort study included febrile children with a bulging fontanelle who underwent lumbar puncture at Meir Medical Center from 2005 through 2015. A total of 764 children ages 2-18 months underwent lumbar puncture during the study period. Among them, 304 had a bulging fontanelle and fever on evaluation and cerebrospinal fluid pleocytosis was found in 115 (37.8%), including 1 case of bacterial meningitis (0.3%). None of the infants described on admission as appearing well on presentation was found to have bacterial meningitis. Of the 764 children who underwent lumbar puncture, 10 infants were diagnosed with bacterial meningitis, and only one (10%) presented with a bulging fontanelle.Conclusion: The finding of a bulging fontanelle has very low sensitivity and specificity for bacterial meningitis. Most causes of a bulging fontanelle in febrile infants are self-limiting diseases. The routine approach of performing a lumbar puncture in febrile infants with a bulging fontanelle should be reconsidered. What is Known: • It is common to perform a lumbar puncture in febrile infants with a bulging fontanelle, to rule out bacterial meningitis. • However, there are only few researches regarding the relationship between bulging fontanelle and bacterial meningitis. What is New: • The finding of a bulging fontanelle has very low sensitivity and specificity for bacterial meningitis • The need for routine lumbar puncture in these cases should be reconsidered.

Extremely Elevated Cerebrospinal Fluid Protein and Glucose Level in a Neonate with Hypernatremic Dehydration

We describe the case of a term newborn who presented with hypernatremic dehydration on day 19 of life. The baby was otherwise hemodynamically stable with no evidence of focal or asymmetric neurological signs. The laboratory tests at the time of admission were negative except for hypernatremia and the extremely elevated levels of cerebrospinal fluid (CSF) protein (717 mg/dL) and glucose levels (97 mg/dL). The hypernatremic dehydration was corrected as per the unit protocol over 48 hours. Repeat CSF analysis done after 5 days showed normalization of the protein and glucose levels. Serial follow-up and neuroimaging showed no evidence of neurological sequelae. Unique feature of our case is this is the first case reporting such an extreme elevation of CSF protein and glucose levels that have had no bearing on neurodevelopmental outcome at 1 month and 3 months of follow-up.