What is the initial treatment approach for a suspected case of meningitis?

Initial Management of Suspected Meningitis

Stabilize airway, breathing, and circulation immediately, obtain blood cultures within 1 hour, perform lumbar puncture within 1 hour if safe to do so, and start empiric antibiotics within the first hour—either immediately after LP or immediately after blood cultures if LP is delayed. 1

Immediate Priorities (First Hour)

Stabilization and Assessment

• Airway, breathing, and circulation stabilization is the absolute first priority before any diagnostic workup begins 1
• Document Glasgow Coma Scale (GCS) score immediately for prognostic assessment and to monitor deterioration 1
• Assess for signs of shock, sepsis, or rapidly evolving petechial/purpuric rash, as these alter the management sequence 1
• Determine need for senior clinician review and ICU admission within the first hour—patients can deteriorate rapidly regardless of initial vital signs 1

Blood Cultures

• Obtain blood cultures within 1 hour of hospital arrival and before any antibiotic administration 1, 2
• Blood cultures are positive in 75% of pneumococcal meningitis, 50-90% of H. influenzae, and 40-60% of meningococcal meningitis 3

Lumbar Puncture Decision Algorithm

Patients WITHOUT Contraindications (No Shock/Sepsis)

• Perform LP within 1 hour of hospital arrival 1
• Start 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 1

Contraindications Requiring Neuroimaging BEFORE LP

Do not perform LP if any of the following are present: 1, 2

• Focal neurological signs
• Papilledema (inability to visualize fundus is NOT a contraindication, especially with short symptom duration) 1
• Continuous or uncontrolled seizures
• GCS ≤ 12
• Immunocompromised state
• History of CNS disease (mass lesion, stroke, focal infection)
• New onset seizure within 1 week

In these cases: Obtain CT head before LP to exclude mass effect and brain swelling that could cause herniation 1, 4

Patients WITH Sepsis or Rapidly Evolving Rash

• Start antibiotics immediately after blood cultures—do NOT perform LP at this time 1
• Begin fluid resuscitation with 500 mL crystalloid bolus over 5-10 minutes 1
• Follow Surviving Sepsis guidelines for ongoing resuscitation 1
• LP can be performed later once patient is stabilized 1

Empiric Antibiotic Therapy

Timing

• Antibiotics must be started within 1 hour of hospital arrival 1, 2
• Delays in antibiotic administration significantly increase mortality 1, 5, 6
• If LP is delayed, perform it within 4 hours of starting antibiotics to maximize culture yield (culture rates drop rapidly after this) 1

Antibiotic Selection for Adults

• Ceftriaxone (or cefotaxime) 2 grams IV PLUS vancomycin for empiric coverage of S. pneumoniae (including resistant strains) and N. meningitidis 4, 3, 7
• Add ampicillin if patient is >50 years old, immunocompromised, or has risk factors for Listeria monocytogenes 3, 7
• In regions with high pneumococcal resistance to third-generation cephalosporins, vancomycin or rifampicin must be added 5, 7

Antibiotic Selection for Children

• Ceftriaxone 100 mg/kg/day (maximum 4 grams daily) for meningitis 8
• Administer in divided doses every 12 hours or once daily 8
• For neonates ≤28 days: ampicillin plus ceftriaxone or gentamicin, with dosing based on gestational and postnatal age 9

Adjunctive Dexamethasone

• Administer dexamethasone before or with the first antibiotic dose to reduce neurological complications and mortality in pneumococcal meningitis 4, 3, 5, 7
• This applies to both adults and children with suspected S. pneumoniae or H. influenzae meningitis 7

Critical Care Considerations

ICU Admission Criteria

• GCS ≤ 12 1
• Seizure activity 4
• Signs of shock or severe sepsis 1
• National Early Warning Score ≥7 requires urgent critical care assessment 1

Monitoring Parameters

• Capillary refill time, blood pressure (mean BP >65 mmHg in adults), pulse quality 1
• Urine output >0.5 mL/kg/hour (requires urinary catheter) 1
• Mental status changes 1
• Lactate levels (target <2 mmol/L) 1

Common Pitfalls to Avoid

• Never delay antibiotics while waiting for LP or neuroimaging—this is the most critical error that increases mortality 1, 2, 5, 6
• Do not perform LP in patients with seizures, altered consciousness (GCS ≤12), or focal neurological signs without prior CT imaging—this risks cerebral herniation 1, 4
• Do not be falsely reassured by normal vital signs or low early warning scores—meningitis patients can deteriorate rapidly 1
• Do not forget to add ampicillin for older adults (>50 years) or immunocompromised patients to cover Listeria 3, 7
• Do not delay dexamethasone—it must be given before or with the first antibiotic dose to be effective 4, 5, 7
• In neonates, administer IV ceftriaxone over 60 minutes (not 30 minutes) to reduce risk of bilirubin encephalopathy 8