Meningitis - A.Prunuske Flashcards
Most common cause of viral meningitis
85% are enteroviruses
(remember late summer and fall)
Also common
HSV-2
HIV
and arthropod-borne
Enteroviruses
Transmission:
Type of genomic material:
Capsid:
Envleope:
Transmission: oral/fecal or respiratory
Type of genomic material: SS(+) RNA
Capsid: icosahedral
Envleope: naked
In a case of septic meningitis, would you do the lumbar puncture before or after the empiric therapy
Do empiric therapy promptly and then do the lumbar puncture
REVIEW
What is the mechanism of action of ceftatriaxone?
Inhibition of transpeptidation of peptidoglycan
REVIEW
What is the mechanism of action of Vancomycin?
Inhibition of transglycosylation of peptidoglycan
The bacterial strain N. meningitidis is known to be resistant to rifampin. Resistance to rifampin is most likely due to a mutation in which gene?
DNA-dependent RNA polymerase
Are strep always in chains?
No ma’am! Can be diplococci as well ( like in pneumonia)
Streptococcus pneumonia- Pneumococcal meningitis!
Why woud you want to give a corticosteroid like dexamethasone right before antibiotic treatment?
Reduce pathology assocaited with inflammation and edema.
Will lead to reduction in hearing loss and other neurological problem possibilties
Ceftriaxone is used for what kinds of infections?
Can it cross BBB?
Used for streptococci and serious Gram- infection
CAN cross BBB
Which type of baterial meningitis is more common among adults and which is most common among young adults and college students????
Adults: Streptococcus pneumonia
Young Adults/College: Neisseria Meningitis
Lipopolysaccharide release from gram(-) bacteria in the cell cause what?
LPS activates macrophages leading to release of NO(hypotension, Shock) and IL-1(fever), and can activate disseminated intravascular coagulation leading to purpuric skin rash.
What can happen if an infant or young child failed to recieve the Hib vaccine?
Infection of Hemophilus influenza type B
What groups are vulnerable to infection by listeria monocytogenes?
Infants less than 2 months old
Adults over 65
Pregnant women
Why are the most common causes of bacterial meningitis in infants under 2 months?
Why might the risk of infection from the most common causes be lower in infants?
Group B Streptococcus
Listeria monocytogenes
Escherichia coli
The risk of infection from the most common causes is lower due to maternal immunity
After screening one of the pregnant women in your practice she is found to have Group B streptococcus. What is your course of action?
To avoid vertical transmission to the infant during birth, give prophylactic penicillin G
Why should you never consume unpasteurized milk, cheese, and deli meats?
Listeria Monocytogenes!
If someone gets listeria after eating a bunch of imported french cheeses, what is your definitive treatment?
ampicillin and gentamicin
What is the 4 drug cocktail used to treat TB and why on earth do you use 4 drugs to treat TB?
Isoniazid
Rifampin
Ethambutol
Pyrazinamide
There have been a lot of problems with resistance to TB drugs. Multiple drug resistant TB has sprung up in many areas. Using 4 drugs helps insure that more resistance will not occur.
What are the mechansims of action for: Isoniazid Rifampin Ethambutol Pyrazinamide
Isoniazid- inhibits mycolic acids (component of mycobacterial cell wall). Acetylation by the liver varies genetically and fast acetylators may require higher dose.
Rifampin- inhibits DNA-dependent RNA polymerase, induces the formation of drug-metabolizing enzymes including cytochrome P450.
Ethambutol- inhibits cell wall synthesis by binding arabinosyl transferase
Pyrazinamide- unknown
What fungal infection can occur in the CNS of immune-compromised individuals?
Cryptococcus Neoformans
What is the treatment for an individual with AIDS who has contracted Cryptococcus Neoformans in the CNS?
Amphotericin + Flucytosine until culture negative followed by fluconazole
for 3-12 months sometimes rest of life.
REVIEW:
What is the mechanism for amphotericin B?
What does the drug target?
- Binds to ergosterol, creating holes in fungal cell membrane
- Broad spectrum invasive fungal infections
REVIEW:
What are the potential side effects of amphotericin?
Does it cross the BBB?
Side effects: Toxic because it binds to cholesterol, decreases renal blood flow and can destroy the basement membrane
BBB: Yes, it crosses the BBB
REVIEW:
What is the mechanism for flucytosine?
What does the drug target?
Mech: Nucleic Acid Synthesis Inhibitor
Spectrum: Yeast only, Candida Albicans and Cryptococcus
