Moffitt Report Pearls 3/2: Bacterial Meningitis and Capnocytophaga

Interesting case of a patient with meningitis from capnocytophaga! Whoa.

Take-home point:

In patients suspected of having bacterial meningitis, these LP results help support the dx (from this JAMA rational clinical exam paper. Thanks Brad!)

  • CSF-blood glucose ratio of 0.4 or less (LR 18)
  • CSF WBC count >500 (LR 15)
  • We don’t really send this, but CSF lactate <31.5 mg/dL (LR 21)

 

Miscellaneous LP teaching points

  • In LP’s done after a seizure, you can expect to see 10-20 WBCs. Definitely <50WBCs. Anything higher than that should make you think of other causes
  • The yield on CSF cultures drops significantly after 6 hours of abx
  • In patients with bacterial meningitis, only 60% have a positive gram stain (on LPs done before abx started)
  • In patients with CSF pleocytosis with PMN predominance (but not slam dunk bacterial meningitis with WBC >1000), think of these possibilities
    • Did the LP early in the course
    • Listeria
    • Parameningeal focus of infection

 

What are the main anaerobes we should know about as human pathogens?

  • Gram negative
    • Bacteroides (most common): intra-abdominal
    • Prevotella: intra-abdominal, soft tissue
    • Fusobacterium: abscess, wound, pulmonary or CNS
    • Porphyromonas: aspiration, periodontal
  • Gram negative
    • Peptostreptococcus: oral, respiratory, intrabdominal
    • Clostridium: pretty big group that we are more familiar with (perfringens, botulinum, difficile)
    • Actinomyces: head, neck, intra-abdominal, aspiration
    • Propionibacterium: foreign bodies

 

Capnocytophaga canimorsus

  • Gram-negative rod, anaerobe
  • Think about with dog bites and dog exposure!
  • Clinical presentation: variable
    • Local wound infection
    • If immunocompromised (esp liver disease, heavy EtOH or asplenic), can have fulminant sepsis presentation with bacteremia and purpuric skin lesions
  • Treatment: look at susceptibilities but treat with beta-lactamase drug (pip-tazo, amox-clav aka “dogmentin” or carbapenem)
  • Check out this CPS Harry and Brad wrote up!
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