Diagnosis and Management of Bacterial Meningitis in the Paediatric Population: A Review

Table 4

Investigations for suspected bacterial meningitis.

Investigation	Comment
Blood:
Full blood count	Neutrophilia suggestive of bacterial infection
Serum glucose	Often low; allows interpretation of CSF glucose
Electrolytes, urea, and creatinine	To assess for complications and fluid management
Coagulation studies	To assess for complications
Blood cultures	Positive in 40–90% depending on organism
Inflammatory markers	Elevation suggestive of bacterial infection; procalcitonin of more value; neither can establish nor exclude diagnosis
CRP, procalcitonin
CSF:
Protein and glucose
Microscopy, culture, and sensitivities	Gram stain: S. pneumoniae—gram +ve cocci; N. menigitidis—gram −ve cocci; H. influenzae—gram −ve rod
Latex agglutination^1	Rapid; not 100% specific or diagnostic
PCR^2	Rapid; good sensitivity, techniques improving
Lactate	Routine use not currently recommended
Imaging: Computed tomography of the head	Indicated for focal neurology, signs of increased intracranial pressure (ICP), deteriorating neurological function, previous neurosurgical procedures, or immunocompromised; May show evidence of hydrocephalus, abscess, subdural empyema, or infarction; Normal scan does not entirely exclude risk of raised ICP
Other: PCR on blood or urine	Useful if CSF not obtainable

¹Latex agglutination depends on laboratory availability; including N. meningitidis, S. pneumoniae, H. influenzae type B, Escherichia coli and group B streptococci.
²PCR depends on laboratory availability; including N. meningitidis, S. pneumoniae, H. influenzae type b, L. monocytogenes, HSV, CMV, Enterovirus and Mycobacterium tuberculosis.