What is the treatment for post-operative meningitis?

Treatment of Post-Operative Meningitis

For post-operative meningitis, immediate treatment with intravenous ceftriaxone 2g every 12 hours or cefotaxime 2g every 6 hours, plus vancomycin 15-20mg/kg every 12 hours is recommended as empiric therapy, with adjustments based on culture results and clinical response. 1

Initial Management

• Stabilization of airway, breathing, and circulation should be the immediate priority 1
• Blood cultures should be taken as soon as possible, ideally within 1 hour of presentation 1
• Lumbar puncture (LP) should be performed if there are no contraindications, to confirm diagnosis and identify causative organism 1
• If LP cannot be performed immediately, empiric antibiotics should be started after blood cultures are taken 1

Indications for Neuroimaging Before LP

• Focal neurological signs
• Presence of papilledema
• Continuous or uncontrolled seizures
• Glasgow Coma Scale (GCS) ≤ 12 1

Empiric Antibiotic Therapy

• For adults <60 years: Cefotaxime 2g IV every 6 hours OR Ceftriaxone 2g IV every 12 hours 1
• For adults ≥60 years: Same as above PLUS Amoxicillin 2g IV every 4 hours (to cover Listeria) 1
• Add Vancomycin 15-20mg/kg IV every 12 hours if penicillin-resistant organisms are suspected or if the patient has had neurosurgery 1
• For post-operative meningitis specifically, coverage for staphylococci and gram-negative organisms is essential, as these are common causative pathogens 2, 3

Adjunctive Therapy

• Dexamethasone 10mg IV every 6 hours should be started on admission, either shortly before or simultaneously with antibiotics 1
• If pneumococcal meningitis is confirmed, continue dexamethasone for 4 days 1
• If another cause of meningitis is confirmed, dexamethasone should be stopped 1

Definitive Therapy Based on Culture Results

For Gram-Positive Organisms:

• Staphylococcus species (common in post-operative meningitis): Vancomycin 15-20mg/kg IV every 12 hours plus rifampicin 600mg orally twice daily 1, 3
• Streptococcus pneumoniae:
  • If penicillin-sensitive: Benzylpenicillin 2.4g IV every 4 hours OR continue ceftriaxone/cefotaxime 1
  • If penicillin-resistant but cephalosporin-sensitive: Continue ceftriaxone/cefotaxime 1
  • If both penicillin and cephalosporin-resistant: Continue ceftriaxone/cefotaxime PLUS vancomycin PLUS rifampicin 1

For Gram-Negative Organisms:

• Acinetobacter species: Meropenem 2g IV every 8 hours plus intraventricular aminoglycoside 2
• Pseudomonas aeruginosa: Ceftazidime or cefepime 2g IV every 8 hours plus an aminoglycoside 2
• Enterobacteriaceae: Continue ceftriaxone/cefotaxime 1

Duration of Therapy

• For pneumococcal meningitis: 10-14 days (14 days if resistant organisms) 1
• For gram-negative meningitis: 21 days 1
• For staphylococcal meningitis: 14-21 days 1
• Consider removal of infected neurosurgical hardware if present 2, 3

Criteria for ICU Admission

• GCS of 12 or less (or a drop of >2 points) 1
• Cardiovascular instability or evidence of sepsis 1
• Frequent seizures or altered mental state 1
• Need for specific organ support 1

Outpatient Parenteral Antibiotic Therapy (OPAT)

OPAT may be considered when:

• Patient is afebrile and clinically improving
• Has received at least 5 days of inpatient therapy
• Has reliable IV access
• Can access medical care 24 hours a day
• Has no other acute medical needs 1

Common Pitfalls and Caveats

• Delayed treatment increases mortality - antibiotics should be given as soon as possible after diagnosis is suspected 1, 4
• Device-related risk factors - duration of external ventricular drainage and intracranial pressure monitoring increases risk of post-operative meningitis 3
• Antibiotic resistance - consider local resistance patterns when selecting empiric therapy 1
• CSF penetration - ensure selected antibiotics have adequate CSF penetration; meropenem has FDA approval for bacterial meningitis in pediatric patients 5
• Bacteriolytic effects - rapid bacterial lysis can increase inflammation; dexamethasone helps mitigate this effect 6