This morning’s lecture at Mass General/Brigham, about CNS infections, was given by Dr. Jay Vyas. A few take-home points (interspersed with my own commentary) if you were unable to attend:
- The “jolt sign” making the headache worse is not sensitive for CSF pleocytosis.
- Obtain blood cultures before giving antibiotics and doing a lumbar puncture.
- A patient with fever, headache, gets an LP and shows WBC 2200, protein 230, glucose 19. What’s the most likely cause?
- Bacterial meningitis, because CSF<20, CSF protein>200, CSF WBC>2000. This is the “rule of 2’s”
- Empiric antibiotic choice for bacterial meningitis should be based on the gram stain from the LP.
- Don’t forget about Listeria!
- Can vaccinations help prevent meningitis? Yes, for H flu, pneumococus, and meningococcus.
- Bacterial meningitis patients should go into droplet precautions initially, because of meningococcus and H flu (I wasn’t aware of the H flu before the lecture).
CNS Shunt infections
- Infected shunts should be removed, but many patients are shunt dependent.
- The reservoir should be tapped by the neurosurgical colleagues to send for gram stain and culture
- Eosinophiia in CSF most commonly represents chronic infection.
- There are no prospective RCTs of treatment of CNS shunt infections
- The majority of pathogens we detect are viruses. Some good epidemiological data comes from the California encephalitis project.
- Bank serum in case you need to do acute/chronic CSF serologies.
- Neurology will send an anti-NMDA receptor (typically in younger women).
- MRI is typically done, but brain biopsy is not.
- We need multiplex PCR assays to speed the diagnosis of multiple viruses.
- A lung cancer patient presents with weakness, headache and brain MRI shows a ring enhancing mass. What treatment to give?
- Ceftriaxone and metronidazole.
- Genetic testing for 16S rRNA sequencing
- Next generation sequencing provides independent sequence data from millions of individual DNA molecules, allowing each fragment to be classified independently.
- Contact http://depts.washington.edu/molmicdx/
- Soon we’ll be doing whole genome sequencing routinely in the micro lab.
Thanks so much for reading! Reading/writing blog posts does take significant time and we all know that time is in short supply. You and I will both get much more out of my blog posts if they lead to discussion/dialogue. If you found this post useful and wouldn’t mind leaving a brief comment/sharing on social media, that would be great. Thank so much! Best regards, Phil