Signs and Symptoms of Meningitis
The classic triad of fever, neck stiffness, and altered mental status occurs in less than 50% of bacterial meningitis cases, making diagnosis challenging—clinicians must maintain high suspicion based on any combination of cardinal features and never rely on the absence of meningeal signs to exclude the disease. 1, 2
Core Clinical Features
Cardinal Symptoms (Most Common)
- Headache occurs in 84% of patients and is one of the most sensitive indicators 3
- Fever is present in 74% of cases, though may be absent in elderly patients 1, 3
- Neck stiffness appears in 74% of patients but is less common in older adults 1, 3
- Altered mental status (median Glasgow Coma Scale 11) is present in a significant proportion and indicates severe disease 1, 3
- Vomiting occurs frequently and, along with headache, serves as a more sensitive indicator of meningeal infection 1, 4
Additional Presenting Features
- Rash (petechial or purpuric) strongly suggests meningococcal disease when present—occurring in 92% of meningococcal cases with rash, though 37% of meningococcal meningitis patients have no rash 1
- Seizures occur in approximately 15% of patients and are associated with worse outcomes 5
- Focal neurological signs suggest complications such as cerebral infarction or abscess 1
- Retroorbital pain may accompany severe headache 6
Critical Age-Related Variations
Elderly Patients (>60 years)
- More likely to present with altered consciousness rather than classic meningeal signs 1, 2
- Less likely to have neck stiffness or fever compared to younger patients 1, 2
- Higher incidence of pneumococcal and Listeria meningitis in this age group 1
Young Adults (16-25 years)
- Second peak incidence of meningococcal disease occurs in this demographic 1, 6
- Viral meningitis is more common than bacterial, especially in women aged 20s-40s 1, 6
- May present with more classic features but can still deteriorate rapidly 6
Meningococcal Sepsis-Specific Features
Patients with meningococcal sepsis can deteriorate rapidly with shock developing quickly—these patients require immediate recognition and aggressive resuscitation. 1
- Rapidly evolving rash (petechial, purpuric, or maculopapular) indicates high mortality risk 1, 5
- Signs of shock: hypotension, poor capillary refill time (>2 seconds), cold extremities, altered mental state 1
- Limb ischemia may develop in severe septic complications 5
- 10-20% of meningococcal disease presents as fulminant sepsis with or without meningitis 1
Physical Examination Findings: Critical Pitfalls
Unreliable Signs
Kernig's sign and Brudzinski's sign should NOT be relied upon for diagnosis—they have sensitivity as low as 5-11% and miss approximately 89% of actual meningitis cases. 1, 2, 4
- While these signs have high specificity (up to 95%), their extremely low sensitivity makes them useless for ruling out disease 1, 2
- Absence of these signs does NOT exclude meningitis 2, 7
More Reliable Indicators
- Nuchal rigidity when present has high predictive value 4
- Combination approach: The presence of at least one cardinal feature (fever, neck stiffness, altered mental status) has 99-100% sensitivity—if ALL three are absent, meningitis is effectively ruled out 2
- Papilledema indicates raised intracranial pressure and contraindicates immediate lumbar puncture 1
Associated Risk Factors and Historical Features
Key Historical Elements to Document
- Contact with another person with meningitis or sepsis 1, 6
- Source of infection: otitis media, sinusitis, upper respiratory tract infection (suggests pneumococcal) 1
- Recent travel history 1, 6
- CSF leak: history of trauma, neurosurgery, rhinorrhea, or otorrhea 1, 8
- Immunocompromising conditions: HIV, asplenia, complement deficiency, diabetes 1, 8
High-Risk Populations
- Skull fracture or CSF leak predisposes to pneumococcal meningitis and recurrent disease 1
- HIV-positive patients have higher incidence and mortality from pneumococcal and meningococcal meningitis 1
- Diabetic patients with poor glycemic control are at increased risk, particularly for Group B Streptococcus 8
Warning Signs of Deterioration
Patients can maintain deceptively normal vital signs until sudden cardiovascular collapse, particularly young adults with meningococcal disease—early recognition of subtle perfusion abnormalities is critical. 5
Immediate Red Flags Requiring ICU Transfer
- Glasgow Coma Scale ≤12 or drop of ≥2 points 1, 5
- Continuous or uncontrolled seizures 1, 5
- Rapidly evolving rash suggesting meningococcal sepsis 5
- Respiratory compromise: hypoxia, increased work of breathing 5
- Signs of impaired perfusion: delayed capillary refill, cold/dusky extremities, decreased urine output (despite normal blood pressure) 5
Subtle Early Deterioration Signs
- Progression of altered mental state: confusion, lethargy, decreasing responsiveness 5
- Metabolic acidosis on arterial blood gas 5
- Frequent seizures even if controlled 5
Documentation Requirements
Upon presentation, clinicians must document: presence or absence of headache, altered mental status, neck stiffness, fever, rash (of any description), seizures, and any signs of shock. 1
- Glasgow Coma Scale should be documented on admission and monitored serially 1, 5
- Vital signs including capillary refill time, extremity temperature, and mental status changes 5
- Concern from the referring physician or family members should always be taken seriously, even when classic features are absent 1
Special Considerations
Atypical Presentations
- 1.5% of bacterial meningitis cases present without any meningeal signs (no nuchal rigidity, Kernig's, Brudzinski's, or bulging fontanelles) despite CSF pleocytosis 7
- These patients may present only with unexplained fever, behavioral changes, or seizures 7
- Subacute presentation with cranial nerve palsies suggests tuberculous meningitis 2