Signs and Symptoms of Meningitis
Meningitis should be suspected in any adult presenting with at least two of the four cardinal symptoms: fever, headache, neck stiffness, or altered mental status—present in up to 95% of cases—though the classic triad of all three occurs in less than half of patients. 1, 2
Core Clinical Features in Adults
The most common presenting symptoms in adults include:
- Headache: Present in 58-87% of cases 1
- Fever: Occurs in 77-97% of cases 1
- Neck stiffness: Present in 65-83% of cases 1
- Altered mental status: Reported in 30-69% of cases 1
The classic triad of fever, neck stiffness, and altered mental status is present in only 41-51% of adult cases, so its absence cannot rule out meningitis. 1, 3
Additional Important Signs
- Rash: Identified in 20-52% of adult patients; when present in the context of meningitis, it indicates meningococcal infection in over 90% of cases 1. The rash is petechial or purpuric in 89% of meningococcal cases, though 37% of meningococcal meningitis patients have no rash 4
- Seizures: More common with pneumococcal disease 4
- Focal neurological symptoms: More likely with pneumococcal meningitis 4
- Reduced consciousness: More common in pneumococcal disease as measured by Glasgow Coma Scale 4
- Vomiting: A nonspecific but common symptom 4
Critical Diagnostic Pitfalls
Do not rely on Kernig's and Brudzinski's signs for diagnosis—they have extremely poor sensitivity (5-11% in adults) despite high specificity. 1, 5 These classic meningeal signs should not be used to rule out meningitis 4.
Clinical signs alone have poor diagnostic accuracy for bacterial meningitis, with neck stiffness having only 31% sensitivity in adults. 1, 5
Age-Related Variations
Elderly patients present differently and are more likely to have altered consciousness but less likely to have neck stiffness or fever. 4 The younger the patient, the more subtle and atypical the symptoms may be 1.
Key Clinical Principles
- Absence of classic symptoms cannot be used to rule out bacterial meningitis 1, 3
- Individual symptoms like fever, vomiting, headache, and neck stiffness occur frequently in primary care and are poor discriminators when taken independently 4
- Combinations of symptoms are more useful for identifying serious disease 4
- Concern from either the referring physician or a relative should always be taken seriously 4
- All patients with suspected meningitis require urgent hospital referral for cerebrospinal fluid examination, as this is essential for diagnosis 4, 1
Specific Etiologic Clues
- Pneumococcal meningitis: More seizures, focal neurological deficits, reduced consciousness; more common in older adults 4
- Meningococcal disease: Petechial/purpuric rash in 61% of cases; more common in adolescents and young adults 4, 1
- Listeria: More common in older adults 4
- Viral meningitis: Commonly occurs in adults aged 20s-40s 4
Rapid hospital admission via emergency ambulance should be arranged so the patient arrives within one hour of community assessment, as bacterial meningitis can deteriorate rapidly. 4