What is the recommended treatment approach for a patient suspected of having meningitis?

Treatment Approach for Suspected Bacterial Meningitis

All patients with suspected bacterial meningitis should receive empirical antibiotics within 1 hour of hospital presentation, with ceftriaxone 2g IV every 12 hours (or cefotaxime 2g IV every 6 hours) as the cornerstone, plus additional agents based on age and immune status. 1, 2, 3

Immediate Actions (Within First Hour)

• Obtain blood cultures immediately but never delay antibiotics beyond 1 hour - blood cultures must be drawn before antibiotics when possible, but treatment takes absolute priority 1, 2
• Do not wait for lumbar puncture or imaging studies - antibiotics must be started within 60 minutes of presentation even if diagnostic procedures are pending 1, 2, 3
• Assess for critical care needs immediately - patients with GCS ≤12, rapidly evolving rash, cardiovascular instability, or uncontrolled seizures require ICU admission 1

Empirical Antibiotic Regimens by Patient Population

Adults <60 Years (Immunocompetent)

• Ceftriaxone 2g IV every 12 hours OR cefotaxime 2g IV every 6 hours 1, 2, 3, 4
• This provides coverage for Streptococcus pneumoniae and Neisseria meningitidis, the most common pathogens in this age group 2, 4

Adults ≥60 Years

• Ceftriaxone 2g IV every 12 hours OR cefotaxime 2g IV every 6 hours PLUS ampicillin 2g IV every 4 hours 1, 2, 4
• The ampicillin addition is essential for Listeria monocytogenes coverage, which becomes increasingly prevalent in older adults 1, 2, 4

Immunocompromised Patients

• Ceftriaxone 2g IV every 12 hours OR cefotaxime 2g IV every 6 hours PLUS ampicillin 2g IV every 4 hours 1, 2, 4
• This applies to patients with diabetes, alcohol misuse, cancer, or on immunosuppressive drugs 1, 2

Recent Travel to High-Resistance Areas

• Add vancomycin 15-20 mg/kg IV every 12 hours OR rifampicin 600mg IV/PO every 12 hours to the base regimen if the patient has traveled within the last 6 months to countries with penicillin-resistant pneumococci 1, 4

Severe Penicillin/Cephalosporin Allergy

• Chloramphenicol 25 mg/kg IV every 6 hours 1
• For patients ≥60 years or immunocompromised with allergy, add co-trimoxazole 10-20 mg/kg (of trimethoprim component) in four divided doses 1, 4

Adjunctive Dexamethasone Therapy

• Give dexamethasone 10mg IV every 6 hours starting with or shortly before the first antibiotic dose 1, 2
• Continue for 4 days if pneumococcal meningitis is confirmed or highly suspected 1
• Stop dexamethasone if another cause is confirmed 1
• Dexamethasone must be initiated within 12 hours of the first antibiotic dose to be effective 1

Pathogen-Specific De-escalation (Once Culture Results Available)

Streptococcus pneumoniae

• Continue ceftriaxone 2g IV every 12 hours or cefotaxime 2g IV every 6 hours for 10-14 days 1, 2, 4
• If penicillin-sensitive (MIC ≤0.06 mg/L), can switch to benzylpenicillin 2.4g IV every 4 hours 1, 2, 4
• If both penicillin and cephalosporin resistant, continue ceftriaxone/cefotaxime plus vancomycin 15-20 mg/kg IV every 12 hours plus rifampicin 600mg IV/PO every 12 hours 1

Neisseria meningitidis

• Continue ceftriaxone 2g IV every 12 hours or cefotaxime 2g IV every 6 hours for 5-7 days 2, 4

Listeria monocytogenes

• Ampicillin 2g IV every 4 hours for 21 days 2, 4

Haemophilus influenzae

• Continue ceftriaxone 2g IV every 12 hours or cefotaxime 2g IV every 6 hours for 10 days 2, 4

Critical Pitfalls to Avoid

• Never delay antibiotics for imaging or lumbar puncture - the 1-hour window is absolute and delays are associated with increased mortality 1, 2, 3
• Never omit ampicillin in patients ≥60 years or immunocompromised - inadequate Listeria coverage is a common and preventable error 1, 2, 4
• Never stop antibiotics when fever resolves - clinical improvement does not equal microbiological cure, and pathogen-specific duration must be completed 2
• Never use calcium-containing IV solutions with ceftriaxone - precipitation can occur, particularly dangerous in neonates 5
• Never give ceftriaxone as a rapid IV push in neonates - administer over 60 minutes to reduce risk of bilirubin encephalopathy 5

Special Considerations for Neonates

• Ceftriaxone is contraindicated in premature neonates and in neonates ≤28 days requiring calcium-containing IV solutions 5
• Administer IV doses over 60 minutes in neonates to reduce risk of bilirubin encephalopathy 5

Outpatient Parenteral Antibiotic Therapy (OPAT)

• Consider OPAT only after at least 5 days of inpatient therapy in patients who are afebrile, clinically improving, have reliable IV access, and can access 24-hour medical care 1, 2
• Use ceftriaxone 2g IV twice daily (or 4g IV once daily after the first 24 hours) for OPAT 1, 2