What are the key components of a physical exam for suspected meningitis?

Physical Examination for Suspected Meningitis

The key components of a physical examination for suspected meningitis include assessment of mental status, vital signs, meningeal signs, neurological examination, and skin examination, with no single sign being sufficiently sensitive to rule out meningitis.

Mental Status Assessment

• Document level of consciousness using Glasgow Coma Scale (GCS) 1
• Assess for altered mental status, including confusion (defined as inability to correctly answer two consecutive questions or follow two consecutive commands) 1
• Decreased level of consciousness is present in 54-69% of adults with bacterial meningitis 1

Vital Signs

• Check for fever (present in 77-97% of adults with bacterial meningitis) 1
• Assess hemodynamic stability (blood pressure, heart rate)
• Look for signs of shock or severe sepsis requiring immediate intervention 1

Meningeal Signs

• Neck stiffness/nuchal rigidity (present in 60-83% of adults with bacterial meningitis) 1
• Kernig's sign: Position patient supine, flex hip 90 degrees, then attempt to extend knee - resistance or pain indicates positive sign 2
• Brudzinski's sign: Involuntary flexion of hips and knees when neck is passively flexed 2
• Jolt accentuation test: Headache worsening when horizontally rotating head 2-3 times per second 1, 2

Important limitations of meningeal signs:

• The classic triad of fever, neck stiffness, and altered mental status is present in only 41-51% of patients 1, 2
• Kernig's and Brudzinski's signs have very low sensitivity (11-30%) but moderate specificity (85-95%) 2, 3
• Jolt accentuation has higher sensitivity (40-60%) but lower specificity (65-75%) than Kernig's and Brudzinski's signs 3
• Recent studies show jolt accentuation's sensitivity is much lower than initially reported, ranging from 21% 4 to 69.6% 5

Neurological Examination

• Assess for focal neurological deficits (present in 15-34% of adults with bacterial meningitis) 1
• Look specifically for:
  • Cranial nerve abnormalities
  • Limb weakness
  • Abnormal pupillary responses
  • Gaze palsies
  • Visual field defects 1
• Check for papilledema (though inability to view the fundus is not a contraindication to lumbar puncture) 1
• Assess for seizures (present in 10-25% of adults with bacterial meningitis) 1

Skin Examination

• Carefully examine for rash, particularly petechial rash (present in 20-52% of adults with meningitis) 1
• A petechial rash is indicative of meningococcal infection in over 90% of cases 1

Clinical Pitfalls and Caveats

1. Do not rely solely on meningeal signs - approximately half of patients with meningitis may not present with typical meningeal signs 3
2. Absence of fever does not rule out meningitis - fever is absent in up to 23% of cases 1
3. Lumbar puncture remains essential - physical examination alone cannot reliably rule out meningitis 6
4. CT before lumbar puncture is indicated if any of the following are present:
   • Focal neurological signs
   • Papilledema
   • Continuous or uncontrolled seizures
   • GCS ≤ 12 1
5. Do not delay antibiotics if lumbar puncture is delayed for any reason, including imaging 1

Special Considerations

• In elderly patients, the presentation may be more subtle with less pronounced meningeal signs
• Immunocompromised patients may have atypical presentations
• Prior antibiotic treatment may modify clinical findings

The physical examination is an important part of the evaluation, but given the limitations of individual signs, a lumbar puncture should be performed in all patients with suspected meningitis unless contraindicated 1.