Episode 219: Meningitis 2.0

We review diagnosing and managing bacterial meningitis in the ED.

Hosts:

Sarah Fetterolf, MD

Avir Mitra, MD

https://media.blubrry.com/coreem/content.blubrry.com/coreem/Meningitis_2_0.mp3

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Tags: CNS Infections, Infectious Diseases, Neurology

Show Notes

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Patient Presentation & Workup

Patient: 36-year-old male, currently shelter-domiciled, presenting with 3 weeks of generalized weakness, fevers, weight loss, and headaches.

Vitals (Initial): BP 147/98, HR 150s, Temp 100.2°F, RR 18, O2 99% RA.

Clinical Evolution: Initial assessment noted cachexia and a large ventral hernia. Following initial workup, the patient became acutely altered (A&O x0) and febrile to 102.9°F.

Physical Exam Findings:

Brudzinski Sign: Positive (knees flexed upward upon passive neck flexion).

Kernig Sign: Discussed as highly specific (resistance/pain during knee extension with hip flexed at 90°).

Meningeal Triad: Fever, nuchal rigidity, and AMS (present in 40% of cases; 95% of patients have at least two of the four cardinal symptoms including headache).

Imaging:

Chest X-ray: Scattered opacities (pneumonia) and a small pneumothorax.

CT Abdomen/Pelvis: Confirmed asplenia (secondary to 2011 GSW/exploratory laparotomy).

Head CT: Ventricle enlargement concerning for obstructive hydrocephalus and diffuse sulcal effacement.

CSF Analysis & Microbiology

Bacterial Meningitis

Opening Pressure: Elevated (Normal is <170 mm H2​O).

Color: Cloudy or turbid.

Gram Stain: Positive in 60%–80% of cases before antibiotics; drops to 7%–41% after antibiotics.

Cell Count: Very high (>1000–2000/mm3 WBC); dominated by neutrophils (>80% PMN).

Glucose: Low (<40 mg/dL); CSF/blood glucose ratio is <0.3–0.4.

Protein: High (>200 mg/dL).

Cytology: Negative.

Viral Meningitis

Opening Pressure: Normal.

Color: Clear or bloody.

Gram Stain: Negative.

Cell Count: Slightly elevated (<300/mm3 WBC); dominated by lymphocytes (<20% PMN).

Glucose: Normal.

Protein: Moderately elevated (<200 mg/dL).

Cytology: Negative.

Fungal Meningitis

Opening Pressure: Normal to elevated.

Color: Clear or cloudy.

Gram Stain: Negative.

Cell Count: Elevated (<500/mm3 WBC).

Glucose: Normal to slightly low.

Protein: High (>200 mg/dL).

Cytology: Negative.

Neoplastic (Cancer-related) Meningitis

Opening Pressure: Normal.

Color: Clear or cloudy.

Gram Stain: Negative.

Cell Count: Elevated (<300/mm3 WBC).

Glucose: Normal to slightly low.

Protein: High (>200 mg/dL).

Cytology: Positive (this is the key differentiator).

Management Protocol

Immediate Treatment: Early administration of antibiotics/antivirals is critical to reduce mortality.

Antibiotics: Ceftriaxone 2g IV q12h + Vancomycin (or Rifampin in cephalosporin-resistant areas).

Listeria Coverage: Add Ampicillin for patients > 50 years old.

Antivirals: Acyclovir 10 mg/kg q8h.

Steroids: Dexamethasone 10 mg IV q6h for 4 days (proven to reduce mortality and improve outcomes).

Surgical Intervention: Neurosurgery performed an emergent EVD in the ED to relieve pressure from obstructive hydrocephalus.

Post-Exposure Prophylaxis: Indicated only for N. meningitidis (not S. pneumoniae) for contacts < 24 hours from diagnosis.

Regimens: Rifampin for 2 days, single-dose Ciprofloxacin, or IM Ceftriaxone (if pregnant).

Stats & Clinical Pearls: Austrian Syndrome

The Triad: Concurrent pneumonia, endocarditis, and meningitis caused by Streptococcus pneumoniae.

Risk