Meningitis - A.Prunuske

Question 1

Most common cause of viral meningitis

Answer 1

85% are enteroviruses
(remember late summer and fall)

Also common
HSV-2
HIV
and arthropod-borne

Question 2

Enteroviruses

Transmission:
Type of genomic material:
Capsid:
Envleope:

Answer 2

Transmission: oral/fecal or respiratory
Type of genomic material: SS(+) RNA
Capsid: icosahedral
Envleope: naked

Question 3

In a case of septic meningitis, would you do the lumbar puncture before or after the empiric therapy

Answer 3

Do empiric therapy promptly and then do the lumbar puncture

Question 4

REVIEW

What is the mechanism of action of ceftatriaxone?

Answer 4

Inhibition of transpeptidation of peptidoglycan

Question 5

REVIEW

What is the mechanism of action of Vancomycin?

Answer 5

Inhibition of transglycosylation of peptidoglycan

Question 6

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?

Answer 6

DNA-dependent RNA polymerase

Question 7

Are strep always in chains?

Answer 7

No ma’am! Can be diplococci as well ( like in pneumonia)

Question 8

Streptococcus pneumonia- Pneumococcal meningitis!

Why woud you want to give a corticosteroid like dexamethasone right before antibiotic treatment?

Answer 8

Reduce pathology assocaited with inflammation and edema.

Will lead to reduction in hearing loss and other neurological problem possibilties

Question 9

Ceftriaxone is used for what kinds of infections?

Can it cross BBB?

Answer 9

Used for streptococci and serious Gram- infection

CAN cross BBB

Question 10

Which type of baterial meningitis is more common among adults and which is most common among young adults and college students????

Answer 10

Adults: Streptococcus pneumonia

Young Adults/College: Neisseria Meningitis

Question 11

Lipopolysaccharide release from gram(-) bacteria in the cell cause what?

Answer 11

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.

Question 12

What can happen if an infant or young child failed to recieve the Hib vaccine?

Answer 12

Infection of Hemophilus influenza type B

Question 13

What groups are vulnerable to infection by listeria monocytogenes?

Answer 13

Infants less than 2 months old
Adults over 65
Pregnant women

Question 14

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?

Answer 14

Group B Streptococcus
Listeria monocytogenes
Escherichia coli

The risk of infection from the most common causes is lower due to maternal immunity

Question 15

After screening one of the pregnant women in your practice she is found to have Group B streptococcus. What is your course of action?

Answer 15

To avoid vertical transmission to the infant during birth, give prophylactic penicillin G

Question 16

Why should you never consume unpasteurized milk, cheese, and deli meats?

Answer 16

Listeria Monocytogenes!

Question 17

If someone gets listeria after eating a bunch of imported french cheeses, what is your definitive treatment?

Answer 17

ampicillin and gentamicin

Question 18

What is the 4 drug cocktail used to treat TB and why on earth do you use 4 drugs to treat TB?

Answer 18

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.

Question 19

What are the mechansims of action for:
Isoniazid
Rifampin
Ethambutol
Pyrazinamide

Answer 19

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

Question 20

What fungal infection can occur in the CNS of immune-compromised individuals?

Answer 20

Cryptococcus Neoformans

Question 21

What is the treatment for an individual with AIDS who has contracted Cryptococcus Neoformans in the CNS?

Answer 21

Amphotericin + Flucytosine until culture negative followed by fluconazole
for 3-12 months sometimes rest of life.

Question 22

REVIEW:
What is the mechanism for amphotericin B?
What does the drug target?

Answer 22

• Binds to ergosterol, creating holes in fungal cell membrane
• Broad spectrum invasive fungal infections

Question 23

REVIEW:
What are the potential side effects of amphotericin?

Does it cross the BBB?

Answer 23

Side effects: Toxic because it binds to cholesterol, decreases renal blood flow and can destroy the basement membrane

BBB: Yes, it crosses the BBB

Question 24

REVIEW:
What is the mechanism for flucytosine?
What does the drug target?

Answer 24

Mech: Nucleic Acid Synthesis Inhibitor

Spectrum: Yeast only, Candida Albicans and Cryptococcus

Question 25

REVIEW:
What are the potential side effects of flucytosine?

Does it cross the BBB?

Answer 25

Toxicity: Bone marrow suppression- follow patient’s cell counts closely

BBB: Yes, crosses into CNS

Question 26

REVIEW:
What is the mechanism for the azoles?
What does the drug target?

Answer 26

Mechanism: binds fungal P-450 enzyme blocks production of ergosterol
Spectrum: Systemic mycoses (dimorphic fungi) and yeast.

Question 27

REVIEW:
What are the potential side effects of the azoles?

Does it cross the BBB?

Answer 27

Toxicity: Drug-Drug interactions, hepatotoxicity, neurotoxicity, alters hormone synthesis- avoid during pregnancy.

BBB: Actively pumped out of the CNS