Today, in Morning Report, we discussed the diagnosis of viral meningitis.
How opportune a moment to firstly review a previous post last month on Bacterial Meningitis.
We discussed the importance of not delaying administration of parenteral medications (antimicrobial therapy +/- dexamethasone) upon suspicion of bacterial meningitis following collection of blood cultures in order to perform a lumbar puncture.
In fact, administration of antibiotics does not change the composition of the CSF cell count, differential, or biochemistry for at least 24 hours. Please click on this link for the abstract to a paper published in 1983 detailing this finding.
However, if one is able to obtain CSF in a safe and timely manner that does not delay patient care, it is certainly preferable, as we recognize from studies, such as this one, that CSF sterilization may occur more rapidly after initiation of parenteral antibiotics than previously suggested, with complete sterilization of meningococcus within 2 hours and the beginning of sterilization of pneumococcus by 4 hours into therapy.
The classic CSF cell count, differential, and biochemistry compositions of different diagnosis can be reviewed here.
Lastly, the most common causes of viral meningitis include enteroviruses, West Nile Virus, and Herpes Simplex Virus (more often type 2).
