What is the initial assessment and treatment for suspected meningitis?

Initial Assessment and Treatment for Suspected Meningitis

Stabilize airway, breathing, and circulation immediately, obtain blood cultures within 1 hour, and administer empiric antibiotics within 1 hour—either immediately after lumbar puncture if no contraindications exist, or immediately after blood cultures if the patient has sepsis, rapidly evolving rash, or contraindications to lumbar puncture. 1, 2

Immediate Priorities (Within First Hour)

Stabilization and Senior Review

• Airway, breathing, and circulation stabilization is the absolute first priority before any diagnostic or therapeutic interventions 1, 3
• Senior clinician and critical care team review must occur within the first hour, as patients can deteriorate rapidly regardless of initial vital signs 1, 3
• Document Glasgow Coma Scale (GCS) score immediately for prognostic value and to monitor changes 1, 3
• Consider early ICU involvement if the patient has rapidly evolving rash, cardiovascular instability, hypoxia, or GCS ≤12 2, 4

Blood Cultures

• Obtain blood cultures within 1 hour of hospital arrival and before any antibiotics are administered 1, 2, 3
• This is non-negotiable even in critically ill patients, as it may be the only microbiologic diagnosis if lumbar puncture is contraindicated 2, 3

Decision Point: Lumbar Puncture Timing

Patients WITHOUT Contraindications (No Sepsis/Shock)

• Perform lumbar puncture within 1 hour of arrival if it is safe to do so 1, 3
• Administer antibiotics immediately after LP is completed, within the first hour 1
• If LP cannot be performed within 1 hour, start antibiotics immediately after blood cultures and perform LP as soon as possible thereafter, ideally within 4 hours of antibiotic initiation to maximize culture yield 1, 3

Patients WITH Contraindications or Sepsis/Shock

Do NOT perform lumbar puncture immediately if any of the following are present: 1, 3

• Focal neurological signs (including abnormal pupils)
• Papilledema
• Continuous or uncontrolled seizures
• GCS ≤12
• Septic shock or rapidly evolving rash

In these patients: 1, 2

• Administer antibiotics immediately after blood cultures are obtained
• Obtain neuroimaging (CT head) before considering LP to exclude mass effect or significant brain swelling that predisposes to cerebral herniation
• Initiate fluid resuscitation with 500 mL crystalloid bolus over 5-10 minutes if septic shock is present
• Follow Surviving Sepsis guidelines for ongoing resuscitation
• LP should not be performed until imaging clears the patient and clinical status stabilizes

Important caveat: Inability to visualize the fundus is NOT a contraindication to LP, especially in patients with short symptom duration 1

Empiric Antibiotic Therapy (Within 1 Hour)

Standard Adult Regimen (<60 years, immunocompetent)

Ceftriaxone 2g IV every 12 hours PLUS Vancomycin 15-20 mg/kg IV every 8-12 hours 2, 5

• This covers Streptococcus pneumoniae (including resistant strains) and Neisseria meningitidis 2
• Ceftriaxone should be infused over 30 minutes in adults 5

Adults ≥60 Years or Immunocompromised

Add Ampicillin/Amoxicillin 2g IV every 4 hours to the standard regimen for Listeria monocytogenes coverage 2

• Risk factors for Listeria include age >50 years, diabetes, immunosuppressive drugs, cancer, and other immunocompromising conditions 2

Neonates and Pediatric Patients

• Neonates: Ampicillin/amoxicillin plus cefotaxime 2
• Children: Cefotaxime or ceftriaxone plus vancomycin 2
• In pediatric meningitis, initial dose is 100 mg/kg ceftriaxone (not to exceed 4g), then 100 mg/kg/day thereafter 5
• Ceftriaxone should be infused over 60 minutes in neonates to reduce risk of bilirubin encephalopathy 5

Critical warning: Do not use ceftriaxone in neonates receiving or expected to receive calcium-containing IV solutions due to risk of fatal precipitation 5

Adjunctive Dexamethasone Therapy

Administer dexamethasone 10mg IV every 6 hours immediately before or simultaneously with the first antibiotic dose 2, 4

• Continue for 4 days if pneumococcal meningitis is confirmed or probable 2
• This reduces mortality and neurological morbidity in pneumococcal meningitis 2

Septic Shock Management

If septic shock is present, target these endpoints: 1

• Capillary refill time <2 seconds
• Mean blood pressure >65 mmHg in adults
• Normal pulses with no differential between peripheral and central
• Warm extremities
• Urine output >0.5 mL/kg/hour
• Normal mental status
• Central venous pressure 8-12 mmHg
• Lactate <2 mmol/L

Administer crystalloid boluses of 500 mL carefully, monitoring for fluid overload, with repeated clinical reassessment 1

Critical Pitfalls to Avoid

• Never delay antibiotics while waiting for LP or neuroimaging—delays increase mortality significantly 2, 3, 6
• Do not perform LP before neuroimaging in patients with contraindications—this risks fatal cerebral herniation 1, 3
• Do not fail to add Listeria coverage in patients >50 years or immunocompromised—this is a common and preventable error 2
• Do not use suboptimal antibiotic doses—adequate CSF penetration requires full dosing 2
• Do not be falsely reassured by normal early warning scores—patients with meningitis can deteriorate rapidly despite initially reassuring vital signs 1

Post-Antibiotic Lumbar Puncture

Even if antibiotics have been started, LP should still be performed as soon as safely possible, preferably within 4 hours of antibiotic initiation 1, 3

• Culture yield drops rapidly after 4 hours, but CSF findings (elevated WBC, decreased glucose, elevated protein) remain diagnostically useful 2, 3
• Send CSF for cell count with differential, glucose, protein, Gram stain, and culture 3