Bacterial Meningitis in the ED: Tap First, Ask Later

-Case-
A 22-year-old college student arrives to the ED with fever, headache, photophobia, and neck stiffness. He’s somnolent and slow to answer questions. His roommate mentions he hasn’t left bed all day and had a seizure earlier. Fever? Headache? Neck stiffness? Uh-Oh…

-Evaluation-
Bacterial meningitis is a life-threatening infection of the meninges. It’s more common in younger adults, the elderly, and in immunocompromised patients.

• Classic Triad = fever, neck stiffness, altered mental status (though it’s actually present in <50% of cases!)
• Other symptoms can include headache, photophobia, vomiting, seizures
• Risk factors are important to keep in mind; think immunosuppression, recent neurosurgery, sinus or ear infections, age extremes, or living in college dorms/military barracks
• Crucial physical exam clues = positive Kernig’s or Brudzinski’s signs, petechial rash, AMS/decreased GCS

Diagnosis in the ED:

• Blood cultures needed from 2 different sites! Make sure these are collected before antibiotics
• Lumbar puncture for CSF analysis is key for diagnosis
  • Make sure you order your CSF studies (cell count, protein, glucose, Gram stain, culture) and opening pressure is often helpful to measure
• Head CT before LP? Only if signs of increased ICP or focal neuro deficits
• Start empiric antibiotics ASAP – don’t delay for LP if your clinical suspicion is high!

Common suspected pathogens are often based on age:

• <1 month: Group B Strep, E. coli, Listeria
• 1 month-50 years: Streptococcus pneumoniae, Neisseria meningitidis
• >50 years or immunocompromised: Listeria, again, is added to our list

-Management-

Empiric Antibiotic Regimens:

• Neonates: empiric abx begin with ampicillin + gentamicin, or an expanded spectrum cephalosporin (eg, cefotaxime, ceftazidime, or cefepime) 
• 18-50 years:
  • Ceftriaxone 2g IV q12h + vancomycin 15-20 mg/kg IV q8-12h
• >50 years or immunocompromised:
  • Add ampicillin 2g IV q4h (for Listeria coverage)
• Dexamethasone (10 mg IV): start before or with first dose of antibiotics
  

-Fast Facts-

• Don’t wait on CT unless you have to! Antibiotics come first
• LP findings in bacterial meningitis: ↑ opening pressure, ↑ WBC (PMNs), ↓ glucose, ↑ protein
• Viral meningitis = normal or mildly elevated opening pressure with a lymphocytic predominance
• Meningococcal meningitis is highly contagious! Start droplet precautions and prophylaxis for close contacts

Headache, fever, and a stiff neck? It’s your cue to act fast. In the ED, early antibiotics and a good spinal tap go a long way. Whether it’s a college student with a headache or an elderly patient with altered mental status, always keep bacterial meningitis on the differential.

Want to learn more? Read our in-depth study guide and listen to our podcast episode on this topic!

Cheers,

Tamir Zitelny, MD

-References-

1. Tunkel AR, Hartman BJ, Kaplan SL, et al. Practice guidelines for the management of bacterial meningitis. Clin Infect Dis. 2004;39(9):1267–1284. doi:10.1086/425368
2. van de Beek D, de Gans J, Tunkel AR, Wijdicks EF. Community-acquired bacterial meningitis in adults. N Engl J Med. 2006;354(1):44–53. doi:10.1056/NEJMra052116
3. Brouwer MC, Tunkel AR, van de Beek D. Epidemiology, diagnosis, and antimicrobial treatment of acute bacterial meningitis. Clin Microbiol Rev. 2010;23(3):467–492. doi:10.1128/CMR.00070-09
4. Hasbun R, Abrahams J, Jekel J, Quagliarello VJ. Computed tomography of the head before lumbar puncture in adults with suspected meningitis. N Engl J Med. 2001;345(24):1727–1733. doi:10.1056/NEJMoa010399
5. Thigpen MC, Whitney CG, Messonnier NE, et al. Bacterial meningitis in the United States, 1998–2007. N Engl J Med. 2011;364(21):2016–2025. doi:10.1056/NEJMoa1005384