What is the appropriate evaluation and treatment approach for a patient suspected of having meningitis?

Evaluation for Meningitis

Immediate Assessment and Stabilization

All patients with suspected meningitis require immediate hospital admission via emergency ambulance with a goal arrival time within one hour of initial assessment. 1

Critical Initial Steps (Within First Hour)

• Stabilize airway, breathing, and circulation first, then document Glasgow Coma Scale (GCS) score to assess severity and monitor for deterioration 2
• Obtain blood cultures within the first hour of hospital arrival, before antibiotic administration 2
• Document presence or absence of: headache, altered mental status, neck stiffness, fever, rash (any type), seizures, and signs of shock (hypotension, poor capillary refill) 1
• Perform pupillary examination immediately - abnormal pupils indicate increased intracranial pressure or brainstem herniation and represent an absolute contraindication to lumbar puncture until neuroimaging is completed 2
• Do not rely on Kernig's sign or Brudzinski's sign for diagnosis as they have variable sensitivity and specificity 1, 3

Lumbar Puncture Decision Algorithm

Proceed with LP Immediately (Within 1 Hour) If:

• No contraindications present 2
• Patient is alert and oriented
• No focal neurological deficits
• No signs of increased intracranial pressure

Absolute Contraindications to Immediate LP:

• Focal neurological signs or abnormal pupils 2
• Papilledema 2
• Continuous or uncontrolled seizures 2
• GCS ≤ 12 2
• Immunocompromised state 2
• History of CNS disease (mass lesion, stroke, focal infection) 2
• New onset seizure within 1 week 2

If any contraindications exist, obtain urgent CT head imaging first to assess for mass effect, significant brain swelling, or midline shift before considering LP 2

Empiric Antibiotic Therapy

Timing is Critical

Antibiotics must be administered within 1 hour of hospital arrival - after LP if no contraindications exist, or immediately after blood cultures if LP is delayed 2. Delaying antibiotics while waiting for LP or neuroimaging increases mortality 2.

Empiric Regimens by Age and Risk Factors:

Adults <60 years (immunocompetent):

• Ceftriaxone 2g IV every 12 hours 4
• Alternative: Cefotaxime 2g IV every 6 hours 4

Adults ≥60 years:

• Ceftriaxone 2g IV every 12 hours PLUS Ampicillin 2g IV every 4 hours (for Listeria coverage) 4

Immunocompromised patients (including diabetics, alcohol misuse):

• Ceftriaxone 2g IV every 12 hours PLUS Ampicillin 2g IV every 4 hours 4

Pediatric patients:

• For meningitis: Initial dose 100 mg/kg ceftriaxone (max 4g), then 100 mg/kg/day (max 4g daily) divided every 12 hours 5
• For other serious infections: 50-75 mg/kg/day divided every 12 hours (max 2g daily) 5

Neonates:

• Administer ceftriaxone over 60 minutes (not 30 minutes) to reduce risk of bilirubin encephalopathy 5
• Contraindicated in premature neonates and neonates ≤28 days requiring calcium-containing IV solutions 5

Adjunctive Dexamethasone

• Administer dexamethasone to children and adults with suspected bacterial meningitis before or at the time of antibiotic initiation 3

CSF Analysis (When LP Performed)

• Gram stain - 97% specificity for rapid bacterial identification 2
• Cell count and differential 2
• Glucose and protein levels 2
• Bacterial culture 2

If antibiotics are given before LP, perform LP within 4 hours of antibiotic initiation when possible to minimize impact on CSF culture results 2

Isolation and Infection Control

Immediate Isolation Protocol

• Place all patients with suspected meningitis in respiratory isolation with droplet precautions until meningococcal disease is excluded 6
• Single room placement required 6
• Surgical masks worn by all individuals in close contact with the patient 6
• Standard infection prevention precautions 6

Duration of Isolation

• Isolation can be discontinued after 24 hours of effective antibiotic therapy (24 hours of IV ceftriaxone, single dose of oral ciprofloxacin, or 48 hours of rifampin) 6

Healthcare Worker Protection

• Post-exposure prophylaxis is indicated ONLY for healthcare workers with direct exposure to respiratory secretions (mouth-to-mouth resuscitation, endotracheal intubation, endotracheal tube management) 6, 4
• Recommended prophylaxis: Ciprofloxacin 500 mg oral single dose for adults >16 years 4
• Alternative: Ceftriaxone 250 mg IM single dose 4
• Ceftriaxone is preferred during pregnancy (ciprofloxacin is contraindicated) 4

Special Considerations for Septic Shock Presentation

• Do not delay antibiotics to don PPE - if initial responders lack appropriate PPE, immediately don it and then begin treatment 6
• Do not perform lumbar puncture in a patient with severe sepsis and hypotension - give antibiotics immediately after blood cultures and defer LP 6
• Eye protection (goggles or face shield) is necessary to protect against droplet exposure 6
• If intubation becomes necessary, upgrade to N95 respirator along with gown, gloves, and eye protection 6

Common Pitfalls to Avoid

• Never delay antibiotics waiting for LP or neuroimaging - this increases mortality 2
• Do not perform LP in patients with signs of increased intracranial pressure without neuroimaging first 2
• Do not rely on classic meningeal signs (Kernig's, Brudzinski's) to rule out meningitis 1
• Remember that elderly patients are more likely to have altered consciousness and less likely to have neck stiffness or fever 1
• Do not forget Listeria coverage (ampicillin) in patients ≥60 years or immunocompromised 4

Monitoring for Complications

• Half of adults with bacterial meningitis develop focal neurologic deficits during their clinical course, and one-third develop hemodynamic or respiratory insufficiency 1
• Perform cranial imaging (MRI preferred, CT acceptable) when intracranial abnormalities are suspected 1
• Common complications include cerebral infarctions, seizures, hydrocephalus, hearing loss, and cognitive deficits 1
• Routine repeated lumbar puncture is not indicated as the yield is limited 1