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