Meningitis Diagnosis and Presentation

Clinical Presentation

Fever is a common but not universal finding in meningitis, reported in 77-97% of adult bacterial meningitis cases, meaning 3-23% of patients may present without fever 1, 2
The classic triad of fever, neck stiffness, and altered mental status is present in only 41-51% of bacterial meningitis cases 1, 2
Clinical signs have low diagnostic accuracy for predicting meningitis, with neck stiffness having a sensitivity of 31% 3, Brudzinski sign having a sensitivity of 9% 2, and Kernig sign having a sensitivity of 11% 1, 2
No single clinical sign of bacterial meningitis is present in all patients 4

Cerebrospinal fluid (CSF) examination remains the cornerstone of diagnosis for suspected meningitis, regardless of the presence or absence of classic symptoms 1, 5
CSF analysis is the principal contributor to the final diagnosis of meningitis with the highest diagnostic accuracy 6
CSF white blood cell count is the best diagnostic parameter for differentiating bacterial meningitis from other diagnoses (area under curve 0.95) 6

Certain populations are at higher risk for atypical presentations, including neonates who often present with nonspecific symptoms 4 and immunocompromised patients who may have blunted inflammatory responses 6
Listeria monocytogenes, the third most common cause of bacterial meningitis overall, is particularly common in immunocompromised patients and the elderly 6

No published diagnostic algorithm for distinguishing bacterial from viral meningitis has 100% sensitivity 1, 3
The ESCMID strongly recommends CSF examination in all children with suspected bacterial meningitis, unless contraindications for lumbar puncture are present 4
In adults with suspected bacterial meningitis, meningitis should not be ruled out solely based on the absence of classic symptoms 1, 2