CSF basics and this patient’s lumbar findings

Show Notes

Core EM Modular CME Course

Maximize your commute with the new Core EM Modular CME Course, featuring the most essential content distilled from our top-rated podcast episodes. This course offers 12 audio-based modules packed with pearls! Information and link below. 

Course Highlights:

• Credit: 12.5 AMA PRA Category 1 Credits™
• Curriculum: Comprehensive coverage of Core Emergency Medicine,  with 12 modules spanning from Critical Care to Pediatrics.
• Cost:
  • Free for NYU Learners
  • $250 for Non-NYU Learners

Click Here to Register and Begin Module 1

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 Factors: Asplenia (due to the spleen’s role in filtering encapsulated bacteria), alcohol use disorder, and immunosuppression.
• Mortality Rate: Extremely high at 28%; mortality is highest when there is CNS involvement.
• Incidence: Worldwide, S. pneumoniae is the leading cause of bacterial meningitis, accounting for 3,000–6,000 cases annually.