What is the role of steroids, such as dexamethasone, in the treatment of bacterial meningitis in adults?

Steroids in Meningitis in Adults

Direct Recommendation

Dexamethasone 10 mg IV every 6 hours for 4 days should be administered to all adults with suspected bacterial meningitis, with the first dose given 10-20 minutes before or simultaneously with the first antibiotic dose. 1, 2, 3

Dosing Protocol

• Standard adult dose: 10 mg IV every 6 hours for 4 days 1, 2, 3
• Critical timing: First dose must be given 10-20 minutes before or at minimum simultaneously with antibiotics 1, 2, 3
• Late initiation window: If antibiotics already started, dexamethasone can still be initiated up to 12 hours after the first antibiotic dose 1

Pathogen-Specific Continuation

Continue for Full 4 Days:

• Pneumococcal meningitis (confirmed or probable): Continue dexamethasone for the full 4-day course 1, 2
• This is where the greatest mortality benefit exists, with reduction from 34% to 14% death rate 1, 2
• Unfavorable outcomes reduced from 52% to 26% 1, 2

Discontinue Immediately:

• Non-bacterial meningitis confirmed: Stop dexamethasone 1, 2, 3
• Other bacterial pathogens identified (not pneumococcal or H. influenzae): Stop dexamethasone 1, 2
• Listeria identified: Discontinue immediately as it may increase mortality 3

Clinical Benefits by Outcome

Mortality Reduction:

• Overall mortality reduced from 15% to 7% in adults with bacterial meningitis 1
• Pneumococcal meningitis mortality specifically reduced from 34% to 14% 1, 2
• Systematic review confirms relative risk of death 0.6 (95% CI 0.4-0.8) 4

Neurological Sequelae:

• Significant reduction in long-term neurological complications 2, 4, 5
• Hearing loss reduced (RR 0.76,95% CI) 6, 5
• Both systemic and neurological complications during hospitalization are reduced 7

Mechanism of Action

Dexamethasone attenuates the subarachnoid space inflammatory response that drives morbidity and mortality in bacterial meningitis 2, 3, 8. Specifically, it reduces:

• Cerebral edema 2, 3
• Increased intracranial pressure 2, 3
• Altered cerebral blood flow 2, 3
• Cerebral vasculitis 2, 3
• Pro-inflammatory cytokine-mediated neuronal injury 2, 3

Critical Pitfalls to Avoid

Timing Errors:

• Never delay antibiotics to give dexamethasone - both can be administered simultaneously 3, 6
• Missing the pre-antibiotic or simultaneous window reduces efficacy, as the benefit comes from preventing inflammatory response to bacterial lysis 6

Inappropriate Continuation:

• Do not continue dexamethasone if Listeria is identified - this may increase mortality 3
• Stop dexamethasone once non-pneumococcal, non-H. influenzae bacterial etiology is confirmed 1

Resistant Pneumococci:

• For suspected pneumococcal meningitis with potential resistance, consider adding rifampin 600 mg PO twice daily to the empirical vancomycin plus third-generation cephalosporin regimen when using dexamethasone 1
• Dexamethasone is still recommended even if the isolate is highly resistant to penicillin and cephalosporins 1

Special Populations

Not Recommended:

• Neonatal bacterial meningitis: Dexamethasone is not recommended 2, 6
• Low-income countries: No beneficial effects identified in studies from resource-limited settings 2, 6

Septic Shock:

• In patients with both meningitis and septic shock, dexamethasone cannot be unequivocally recommended, though lower doses may be reasonable 8

Safety Profile

• Adverse events are not significantly increased with dexamethasone use 4, 5
• Gastrointestinal bleeding occurs in approximately 1% of steroid-treated patients versus 4% of placebo patients 4
• Secondary fever, GI bleeding, and psychiatric manifestations may be more common but neurological complications are significantly reduced 9

Evidence Quality

The 2016 UK Joint Specialist Societies guideline provides Grade 1A evidence for initiating dexamethasone on admission 1. This is supported by the landmark European Dexamethasone Study (2002) which demonstrated clear mortality benefit in a well-powered, prospective, randomized, placebo-controlled trial 1, 8, 5. Multiple systematic reviews confirm consistent benefit across studies 4, 5.