Table 1.

Clinical definition and classification of CNS infection based on laboratory features of CNS infections among children.

Clinical definition (Included criteria)*	Features
Age	0–16 years
Fever	≥38°C
Clinical features	At least one:
	Stiff neck Altered/reduced consciousness Focal neurological signs Convulsion Bulging fontanelle if <12 months of age Irritability if <5 years of age Headache if <5 years of age Prostration • Petechial or purpuric rash
Laboratory investigation	Lumbar puncture performed, or planned at the time of assessment, by clinical team
CNS infection classification based on laboratory feature	Features (in addition to meeting clinical case definition)
Confirmed	Pathogen detected in CSF by culture and/or PCR OR Positive serology in CSF OR Positive blood culture AND purulent CSF (WBC ≥100 cells/μL OR [WBC 10–99 cells/μL AND glucose <2.2 mmol/L or protein >1.0 g/L]) OR Purulent CSF AND positive CSF Gram stain
Probable	Purulent CSF AND absence of identifiable pathogens by culture, Gram stain, PCR, or serology** OR Abnormal CSF (WBC 10–99 cells/μL AND normal protein/glucose) AND positive blood culture and/or positive CSF Gram stain
Suspected	Non-purulent CSF AND absence of identifiable pathogens by culture, PCR, or serology

Note: *For study enrolment, all four criteria had to be met (age, fever, clinical features, and laboratory).

**Pathogen-negative probable cases were re-categorized as suspected cases if laboratory testing was incomplete.

CNS: central nervous system, CSF: cerebrospinal fluid, WBC: white blood cell, PCR: Polymerase Chain Reaction.