What are the physical exam tests for meningitis?

Physical Examination Tests for Meningitis

The key physical examination tests for meningitis include nuchal rigidity, Kernig's sign, Brudzinski's sign, and jolt accentuation of headache, though these tests have limited sensitivity and should not be used to rule out meningitis when clinical suspicion is high.

Classic Meningeal Signs

Nuchal Rigidity

• Resistance to passive flexion of the neck is the most commonly observed meningeal sign 1
• Sensitivity of approximately 30% in adults with suspected meningitis 2
• Higher sensitivity (60-65%) compared to other meningeal signs, but still misses many cases 3

Kernig's Sign

• Positive when pain is elicited by extending the knee while the hip is flexed 4
• Very low sensitivity (approximately 5%) in adults 2
• Higher specificity (85-95%) compared to nuchal rigidity 3

Brudzinski's Sign

• Positive when flexion of the neck causes involuntary flexion of the hips and knees 4
• Similar to Kernig's sign, has very low sensitivity (approximately 5%) 2
• Higher specificity (85-95%) compared to nuchal rigidity or jolt accentuation 3

Jolt Accentuation

• Positive when horizontal rotation of the head (2-3 times per second) worsens headache 1
• Initially reported to have high sensitivity, but more recent studies show moderate sensitivity (40-60%) 3, 5
• In patients with undisturbed consciousness, sensitivity may be higher (75.2%) 5

Diagnostic Value and Limitations

• The classic triad of fever, neck stiffness, and altered mental status is present in only 41-51% of adults with bacterial meningitis 1
• No single physical examination finding has sufficient sensitivity to rule out meningitis 1, 3
• Approximately half of patients with meningitis may not present with typical meningeal signs 3
• Combining several examinations may decrease the risk of misdiagnosis 3

Clinical Approach Based on Setting

Conventional Setting

• Lumbar puncture remains the gold standard for diagnosis unless contraindicated 1
• CT scan should be performed before lumbar puncture if there are focal neurologic findings suggesting disease above the foramen magnum 1

Contingency Setting (Limited Resources)

• Consider meningitis if two or more of the following are present:
  • Severe headache
  • Altered mental status (inability to correctly answer two consecutive questions or follow commands)
  • Meningeal signs (Kernig's sign, Brudzinski's sign, jolt accentuation, nuchal rigidity, photophobia)
  • Other neurological symptoms/signs (seizures, focal signs, papilledema) 1

Crisis Setting

• Consider meningitis with any of the following:
  • Severe headache
  • Altered mental status
  • Meningeal signs
  • Other neurological symptoms/signs 1

Special Considerations

• In children, the most common clinical characteristics are fever (92-93%), headache (78%), neck stiffness (40-82%), and vomiting (58-67%) 1
• Meningeal signs have poor test characteristics in differentiating bacterial from viral/aseptic meningitis 1
• In neonates, meningitis often presents with nonspecific symptoms rather than classic meningeal signs 1
• A petechial rash is identified in 20-52% of adults with bacterial meningitis and is indicative of meningococcal infection in over 90% of cases 1

Clinical Pitfalls

• Absence of meningeal signs does not rule out meningitis, especially in immunocompromised patients 1
• If bacterial meningitis is suspected and lumbar puncture is delayed for any reason (including imaging), appropriate empirical antibiotic therapy should be started after blood cultures are obtained 1
• Relying solely on physical examination findings may lead to missed diagnoses, as the sensitivity of all meningeal signs is suboptimal 3, 2
• In patients with severe meningeal inflammation (≥1000 WBCs/mL of CSF), nuchal rigidity may have better diagnostic value (sensitivity and negative predictive value of 100%) 2