Table 1

Clinical case definitions for classification of children with suspected CNS infection
Clinical and initial investigatory criteria Microbiological & virological confirmation
Encephalopathy only Altered consciousness with no evidence of typical abnormalities in imaging or CSF analysis (i.e. CSF white cell count <5/ml)
Encephalitis Altered consciousness with no other cause identified & evidence of typical abnormalities in imaging or CSF analysis (i.e. CSF white cell count ≥5/ml) Defined as ‘microbiologically/virologically confirmed' if a pathogen was identified by culture or PCR of the CSF
Meningism only Meningism (neck stiffness, bulging fontanelle and/or photophobia) without evidence of altered consiousness and no evidence of typical abnormalities in imaging or CSF analysis (ie white cell count <5/ml)
Purulent Meningitis Febrile illness or meningism with no altered consciousness & CSF WCC >1000/ml or between 100 and 1000/ml with a predominance of polymorphonuclear cells and a CSF: plasma glucose ratio <0.5 (or unpaired CSF glucose <5 mmol) Defined as 'microbioloigcally confirmed' if a pathogen was identified by culture or PCR of the CSF or blood
Aseptic meningitis Febrile illness or meningism with no altered consciousness with a normal CSF: plasma glucose ratio (>0.5) & either a CSF white cell count of 5-20/ml, or 20- 1000/ml with a lymphocyte predominance Defined as ‘microbiologically/virologically confirmed’ if a pathogen was identified by culture or PCR of the CSF or blood

Kelly et al.

Kelly et al. BMC Pediatrics 2012 12:145   doi:10.1186/1471-2431-12-145

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