Emergency Medicine · Year 3 · from Emergency Medicine

Case 3: Bacterial Meningitis - The Adult with Headache and Fever

Patient Demographics

• Age: 45 years
• Sex: Female
• Occupation: Elementary school teacher

Chief Complaint

"I have the worst headache of my life and I can't stand the light."

History of Present Illness

A 45-year-old female presents with 24 hours of progressively worsening headache, now 10/10 severity. She developed fever, neck stiffness, and photophobia overnight. Her husband reports she has been increasingly confused over the past few hours. She had a mild upper respiratory infection last week that seemed to resolve. No recent travel or sick contacts with similar symptoms.

Initial Assessment

ESI Level: 1 - Suspected bacterial meningitis

First Impression:

• Appearance: Ill-appearing, eyes closed, minimal movement
• Work of breathing: Normal
• Circulation: Flushed

Vital Signs:

• Heart rate: 108 bpm
• Blood pressure: 138/82 mmHg
• Respiratory rate: 18 breaths/min
• SpO2: 97% on room air
• Temperature: 39.4C (102.9F)
• GCS: 13 (E3V4M6)

Classic Triad of Meningitis

Note: Classic triad present in only 44% of adults with bacterial meningitis

Primary Survey

Airway: Patent Breathing: Normal Circulation: Tachycardic, well-perfused Disability: Confused, photophobic, meningeal signs present Exposure: No rash (important - no petechiae)

Meningeal Signs Examination

Nuchal Rigidity: Present - passive neck flexion causes resistance and pain

Kernig Sign: Positive - resistance/pain with knee extension when hip flexed

Brudzinski Sign: Positive - passive neck flexion causes hip/knee flexion

Jolt Accentuation: Positive - horizontal head rotation worsens headache

Critical Decision Point: CT Before LP?

Indications for CT Before LP:

• Immunocompromised state
• History of CNS disease
• New-onset seizure
• Papilledema
• Altered level of consciousness ✓
• Focal neurologic deficit

This Patient: Has altered mental status → CT before LP indicated

CRITICAL: Do NOT delay antibiotics for CT or LP

Management Timeline

Time 0 (arrival):

• Clinical assessment: Suspected bacterial meningitis
• Blood cultures obtained

Time 15 minutes:

• Dexamethasone 0.15 mg/kg IV (give BEFORE or WITH first antibiotic dose)
• Ceftriaxone 2g IV
• Vancomycin 25 mg/kg IV
• Acyclovir 10 mg/kg IV (HSV coverage given altered mental status)

Time 45 minutes:

• CT head: No mass effect, no contraindication to LP

Time 60 minutes:

• Lumbar puncture performed

Secondary Survey

SAMPLE History:

• Symptoms: Headache, fever, neck stiffness, photophobia, confusion
• Allergies: None
• Medications: Metformin, lisinopril
• PMH: Type 2 diabetes, hypertension, no immunosuppression
• Last Meal: Yesterday evening
• Events: URI last week, then progressive symptoms

Physical Examination:

HEENT:

• Photophobia present
• No papilledema on fundoscopy
• Ears: No otitis media

Neurological:

• Oriented to person only
• No focal motor deficits
• Cranial nerves intact
• Meningeal signs positive

Skin:

• No petechiae or purpura (would suggest meningococcemia)

Diagnostic Testing

Lumbar Puncture Results:

Labs:

• WBC: 18,400 with left shift
• BMP: Normal except glucose 142
• Procalcitonin: 8.4 ng/mL

CSF Interpretation:

• High WBC with neutrophil predominance + low glucose + high protein = BACTERIAL MENINGITIS

Diagnosis

Acute Bacterial Meningitis - Streptococcus pneumoniae (based on Gram stain)

Antibiotic Adjustment

Based on Gram Stain (Gram-positive diplococci = pneumococcus):

• Continue ceftriaxone + vancomycin (until sensitivities)
• Continue dexamethasone (proven benefit for pneumococcal meningitis)
• Discontinue acyclovir (not HSV)

Culture Results (48 hours):

• CSF culture: Streptococcus pneumoniae (penicillin MIC 0.06 = sensitive)
• Blood cultures: S. pneumoniae

Antibiotic De-escalation:

• Discontinued vancomycin (sensitive to ceftriaxone)
• Continued ceftriaxone 2g IV q12h x 10-14 days

Dexamethasone in Meningitis

Evidence: Reduces mortality and neurological sequelae in pneumococcal meningitis

Dosing: 0.15 mg/kg (max 10mg) q6h x 4 days

Timing: Must be given BEFORE or WITH first antibiotic dose

When to use: All suspected bacterial meningitis (adult); primarily benefits pneumococcal

Clinical Course

Day 1-2: Continued antibiotics, steroids, supportive care; remained in ICU

Day 3: Mental status improving, GCS 15

Day 5: Transferred to floor

Day 10: Completed antibiotics, hearing evaluation (normal)

Disposition: Discharged day 12

Teaching Points

1. Give antibiotics immediately: Don't delay for LP or CT; mortality increases with delays
2. Dexamethasone timing critical: Before or with first antibiotic dose; reduces mortality in pneumococcal meningitis
3. CT before LP only if indicated: Altered mental status, focal findings, immunocompromised, papilledema
4. Classic triad uncommon: All three (fever, neck stiffness, AMS) present in <50%
5. CSF findings: High WBC (neutrophils), low glucose (ratio <0.4), high protein = bacterial
6. Empiric coverage: Ceftriaxone + vancomycin ± ampicillin (if >50 or immunocompromised for Listeria)
7. Hearing loss: Common sequela; all patients need audiometry before discharge
8. Chemoprophylaxis: Close contacts need prophylaxis for meningococcal meningitis

Clinical Image

Image Description: Cerebrospinal fluid samples comparing normal clear CSF with turbid/cloudy CSF characteristic of bacterial meningitis due to elevated white blood cells and protein.

Attribution: Image from Wikimedia Commons, Cerebrospinal fluid in meningitis. Licensed under CC BY-SA 3.0. Source: https://commons.wikimedia.org/wiki/File:Csf-samples-702x336.jpg

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