Bacterial Meningitis in the Absence of Pleocytosis in Children A Systematic Review

One of the main features of bacterial meningitis is pleocytosis. However, when children with meningitis present within hours of onset of symptoms, there is the possibility that the meninges are not yet sufficiently inflamed to lead to a raised cerebrospinal fluid (CSF) white blood cell count. A systematic search was done to identify published studies reporting children with culture- or polymerase chain reaction-proven bacterial meningitis in the absence of pleocytosis. We identified 26 studies describing 62 children (18 neonates). In those in whom fever duration was specified, 32 (80%) of 40 had a fever for less than or equal to 24 hours before lumbar puncture (LP). In those in whom the glucose level was reported, it was normal in 14 (82%) of 17 neonates and 33 (80%) of 41 older infants and children. The protein level was normal in 8 (44%) of 17 neonates and 32 (80%) of 40 older infants and children. Twelve of the 62 children had a Gram stain of their CSF and this was positive in 2 (17%). Simultaneous blood cultures were positive in 5 (28%) of 18 neonates and 21 (68%) of 31 older infants and children. There was no association between the absence of pleocytosis and particular bacteria. All of the 10 children who had a second LP had an abnormal CSF including pleocytosis. These findings indicate that the absence of pleocytosis does not exclude bacterial meningitis reliably and should be interpreted in the context of the duration of illness. CSF samples, particularly those from cases with relatively short symptom duration, should be cultured even when the cell count and biochemistry are normal. A second LP can be helpful when bacterial meningitis is suspected despite a normal initial CSF.

Automated summary

Bacterial meningitis can present without pleocytosis, especially in children who experience symptoms shortly after onset. It is important to culture cerebrospinal fluid samples from patients with relatively short symptom duration, even if cell counts and biochemistry appear normal. A second lumbar puncture may be necessary in suspected cases of bacterial meningitis with initially normal CSF findings.