What is the recommended treatment for an adult patient with suspected meningitis and no significant medical history?

Treatment of Suspected Meningitis in Adults Without Significant Medical History

For an adult with suspected meningitis and no significant medical history, immediately administer dexamethasone 10 mg IV followed by empiric antibiotics (ceftriaxone 2g IV twice daily plus vancomycin) within the first hour of hospital arrival, ideally after obtaining blood cultures and performing lumbar puncture if no contraindications exist. 1, 2

Immediate Priorities (Within First Hour)

Initial Assessment and Stabilization

• Stabilize airway, breathing, and circulation first 2
• Document Glasgow Coma Scale (GCS) score immediately to assess severity and monitor for deterioration 1, 2
• Obtain blood cultures within 1 hour of arrival, before antibiotics 2, 3
• Assess for signs of shock, sepsis, or rapidly evolving rash that would alter management 1, 2

Determining Lumbar Puncture Timing

Perform lumbar puncture within 1 hour if NO contraindications exist 2. However, defer LP and proceed directly to antibiotics if any of the following are present: 1, 2

• GCS ≤ 12 or drop of >2 points
• Focal neurological signs or abnormal pupils
• Papilledema
• Continuous or uncontrolled seizures
• New onset seizure within 1 week
• Immunocompromised state
• History of CNS disease (mass lesion, stroke, focal infection)

If LP is contraindicated, obtain CT head imaging urgently to assess for mass effect, brain swelling, or midline shift before considering LP 2, 4. Never delay antibiotics waiting for imaging or LP - this significantly increases mortality 2, 4, 5.

Empiric Antibiotic and Adjunctive Therapy

Dexamethasone Administration

Give dexamethasone 10 mg IV every 6 hours, starting either shortly before or simultaneously with the first antibiotic dose 1, 6. This is a Grade 1A recommendation that reduces mortality and neurological complications in pneumococcal meningitis 1.

• If antibiotics were already started, still initiate dexamethasone up to 12 hours after the first antibiotic dose 1
• Continue dexamethasone for 4 days if pneumococcal meningitis is confirmed or thought probable 1
• Stop dexamethasone if another cause is confirmed or thought probable 1

Antibiotic Regimen

For immunocompetent adults, empiric therapy consists of: 4, 3

• Ceftriaxone 2g IV twice daily (or cefotaxime as alternative) 1, 7
• PLUS Vancomycin to cover penicillin-resistant Streptococcus pneumoniae 4, 3

Ceftriaxone dosing specifics: 1, 7

• Give twice daily for the first 24 hours to achieve rapid CSF sterilization 1
• After 24 hours, can transition to once daily dosing (4g IV once daily) in stable patients 1
• Administer over 30 minutes IV infusion 7

Timing of Antibiotic Administration

Antibiotics must be given within 1 hour of hospital arrival 2, 5. The specific sequence depends on LP feasibility: 2

• If LP can be performed immediately (no contraindications): Blood cultures → LP → Dexamethasone + Antibiotics
• If LP is delayed (contraindications present): Blood cultures → Dexamethasone + Antibiotics immediately → LP within 4 hours if possible 2

Critical Care Considerations

ICU Transfer Criteria

Involve intensive care teams early and transfer to critical care if: 1

• Rapidly evolving rash
• GCS ≤ 12 or drop of >2 points
• Evidence of limb ischemia
• Cardiovascular instability or severe sepsis
• Acid/base disturbance or hypoxia
• Respiratory compromise
• Frequent or uncontrolled seizures
• Altered mental state

Strongly consider intubation if GCS < 12 1. Patients with meningococcal sepsis can maintain blood pressure until late in disease, then deteriorate rapidly - examine for delayed capillary refill time and cold/dusky extremities 1.

Severe Sepsis Management

If severe sepsis is present, manage in critical care setting following Surviving Sepsis guidelines with fluid resuscitation using crystalloid boluses 1, 4

Infection Control

Isolation Requirements

Place all patients with suspected meningitis in respiratory isolation with droplet precautions until meningococcal disease is excluded 8. This includes:

• Single room placement
• Surgical masks for all individuals in close contact
• Standard infection prevention precautions

Discontinue isolation after 24 hours of effective antibiotic therapy (ceftriaxone or single dose ciprofloxacin) 8

Common Pitfalls to Avoid

• Never delay antibiotics while waiting for LP or neuroimaging - this increases mortality significantly 2, 4, 5
• Do not perform LP before neuroimaging in patients with contraindications (GCS ≤12, focal signs, seizures) - this risks cerebral herniation 1, 2, 4
• Do not use glycerol as adjuvant therapy - it is not recommended for community-acquired bacterial meningitis in adults 1
• Do not use therapeutic hypothermia - it is not recommended for adults with bacterial meningitis 1
• Do not underestimate severity based on initial vital signs - patients can deteriorate rapidly even with reassuring early warning scores 1, 4

Duration and Follow-up

Continue antibiotic therapy for at least 2 days after signs and symptoms resolve 7. Usual duration is 7-14 days for most bacterial meningitis, though complicated infections may require longer therapy 4, 7. For Streptococcus pyogenes, continue therapy for at least 10 days 7.

Tailor antibiotics once culture results and sensitivities return 4. No dosage adjustment is necessary for renal or hepatic impairment with ceftriaxone 7.