What is the appropriate management for a patient with suspected meningitis and elevated WBC and CRP?

Management of Suspected Meningitis with Elevated WBC and CRP

Immediately administer empiric antibiotics within 1 hour of hospital arrival—specifically ceftriaxone 2g IV every 12 hours (or cefotaxime 2g IV every 6 hours) plus vancomycin 15-20 mg/kg IV every 8-12 hours—after obtaining blood cultures but without waiting for lumbar puncture results. 1, 2

Immediate Time-Critical Actions (Within First Hour)

Stabilization and Assessment:

• Stabilize airway, breathing, and circulation as the immediate priority 1
• Document Glasgow Coma Scale (GCS) for prognostic value and monitoring 1
• Obtain blood cultures before antibiotics, but do not delay antibiotic administration beyond 1 hour 1, 2, 3
• Assess for signs of shock, severe sepsis, or rapidly evolving rash 1

Decision Point for Lumbar Puncture:

• Determine if CT scan is needed before lumbar puncture by assessing for: age ≥60 years, immunocompromise, history of CNS disease, new-onset seizure, altered mental status, focal neurological deficits, or papilledema 2, 3
• If no CT indications present, perform lumbar puncture within 1 hour after starting antibiotics 1
• If CT is indicated, perform it after antibiotics are started; only proceed with LP if no mass effect or elevated intracranial pressure 2
• Critical caveat: Never delay antibiotics for imaging—antibiotics must be given within 1 hour regardless of LP timing 1, 2

Empiric Antibiotic Regimens

Standard Adult Regimen (<60 years):

• Ceftriaxone 2g IV every 12 hours OR cefotaxime 2g IV every 6 hours 1
• PLUS vancomycin 15-20 mg/kg IV every 8-12 hours 1, 2
• Vancomycin is essential for coverage of penicillin-resistant pneumococci, which remain a concern despite decreased prevalence 4

Modified Regimen for High-Risk Patients (≥60 years or immunocompromised):

• Same cephalosporin plus vancomycin as above 1, 2
• PLUS amoxicillin 2g IV every 4 hours for Listeria monocytogenes coverage 1, 2
• Risk factors for Listeria include age >50 years, diabetes, immunosuppressive drugs, cancer, and alcohol misuse 1, 2

Geographic Resistance Considerations:

• If patient traveled within last 6 months to areas with high pneumococcal resistance, add vancomycin 15-20 mg/kg IV every 12 hours OR rifampicin 600mg IV/PO every 12 hours 1, 5

Penicillin Allergy:

• If clear history of anaphylaxis to penicillins or cephalosporins, use chloramphenicol 25 mg/kg IV every 6 hours 1

Adjunctive Dexamethasone Therapy

Administration Protocol:

• Give dexamethasone 10mg IV every 6 hours immediately before or simultaneously with first antibiotic dose 2, 5, 3
• Can still be initiated up to 12 hours after first antibiotic dose if not given initially 5
• Continue for 4 days if pneumococcal meningitis is confirmed or probable 2, 5
• This reduces mortality and neurological morbidity in pneumococcal meningitis 2

Critical Care Considerations

Indications for ICU Transfer:

• GCS ≤12 (or drop >2 points) 2, 5
• Rapidly evolving rash 1, 2
• Cardiovascular instability or signs of shock 1, 2
• Hypoxia or respiratory compromise 2, 5
• Uncontrolled seizures 5
• Strongly consider intubation if GCS <12 2, 5

Sepsis Management:

• If predominantly sepsis or rapidly evolving rash present, give antibiotics immediately after blood cultures 1
• Commence fluid resuscitation immediately with initial bolus of 500 mL crystalloid 1
• Follow Surviving Sepsis guidelines 1
• Do not perform LP at this time 1

Diagnostic Interpretation

CSF Findings Supporting Bacterial Meningitis:

• Elevated WBC typically >2,000 leukocytes/mm³ or >1,180 neutrophils/mm³ 3
• CSF glucose <40% of serum glucose (hypoglycorrhachia predicts bacterial meningitis with 99% certainty) 2, 3
• Elevated protein 3
• Gram stain is highly specific (97%) for bacterial meningitis 3

Serum CRP Interpretation:

• CRP >50 mg/L in patients with CSF pleocytosis usually indicates bacterial etiology 6
• In children <6 years, discriminatory level of 20 mg/L can distinguish bacterial from viral meningitis 6
• If illness duration <12 hours, CRP below discriminatory levels has limited diagnostic value 6

Common Pitfalls to Avoid

• Delaying antibiotics for imaging: Antibiotics must be given within 1 hour regardless of imaging needs 2
• Inadequate Listeria coverage: Always add ampicillin/amoxicillin for patients ≥60 years or immunocompromised 1, 2
• Omitting vancomycin: Essential for resistant pneumococcal coverage despite decreased prevalence 4
• Forgetting dexamethasone: Must be given before or with first antibiotic dose for maximum benefit 2, 5
• Insufficient dosing: Use full doses to achieve adequate CSF penetration 5
• Not obtaining blood cultures: Must be drawn before antibiotics, though this should not delay treatment 1, 2, 3

Duration of Therapy (Once Pathogen Identified)

• Pneumococcal meningitis: 10-14 days (longer if delayed clinical response) 1, 5
• Meningococcal meningitis: 5-7 days 1, 5
• Listeria monocytogenes: 21 days 5
• Haemophilus influenzae: 10 days 5