CNS Infection Cases - Frank Flashcards
A patient presents with bacterial meningitis symptoms. What organism is most likely if the patient is:
An infant who recently immigrated?
A military recruit who is in basic training?
An AIDS patient?
Haemophilus influenzae- vaccinated against in the US, seen in very young immigrants
Neisseria Meningitidis- seen in groups of younger people living together in close quarters EG dorms, barracks
Cryptococcus neoformans- seen in severely immunocompromised patients EG AIDS, organ transplant
A patient presents with bacterial meningitis symptoms. What organism is most likely if the patient is:
An alcoholic?
presenting with less sever symptoms in the summer?
presenting following spinal surgery?
Listeria monocytogenes- hits those who are immunocompromised, particularly alcoholics who are at a higher risk due to vomitting
Enterovirus- typically present with less severe symptoms and are more common in the summer
Staphylococcus Epidermidis- typically presents after injectionor surgery which would introduce bacteria from the skin into the CSF
What is the most common cause of meningitis?
What aspects of the history might indicate the cause of meningitis?
Streptococcus pneumoniae
Age, Severity of disease, Season, Accompanying Symptoms, Immunological Risk Factors
What does the glucose level in the CSF tell us about the cause of meningitis?
What does the presence of immune cells in the CSF tell us about the cause of meningitis?
Low glucose levels indicate a bacterial infection; slightly low to normal glucose levels indicate viral etiology
PMNs indicate a bacterial infection while mononuclear cells indicate a partially treated bacterial infection, TB, or viral infection
What 2 tests (1 general, 1 specific) can be done on the CSF to narrow down the cause of infection?
A gram stain
PCR
What is the course of treatment if the patient’s CSF stains gram positive?
What is the course of treatment if the patient’s CSF stains gram negative?
Gram Positive
- Ceftriaxone to cover gram positive bugs
- Vancomycin in case the bug is penicillin resistant
- Corticosteroids to decrease parenchymal inflammation
_Gram Negative _
- Ceftriaxone, Vancomycin to cover gram positive bugs
- Corticosteroids to decrease inflammation
- Ampicillin covers many gram negatives
Only 50% of gram positive infections end up staining gram positive, so must treat for both.
What are the three basic tenets for treating bacterial meningitis?
- Use cidal drugs since the brain is an immunopriveledged
- Give high, frequent doses since antibiotics do not concentrate very well in the CSF
- Treat promptly since infections can progress very rapidly NEVER WAIT FOR CULTURE
What is the only treatable viral encephalitis?
What viral causes are most common in summer?
Herpes Simplex Virus
Arbovirus
How is HSV encephalitis treated?
What is seen on an MRI?
High dose acyclovir
Cortical enhancement, especially in the temporal lobes
