Intro To Meningitis Flashcards
What are the three main symptoms with meningitis?
Fever
Headache
Stiff neck (30% of cases)
Can get nausea
Vomiting
Where does meningitis develop?
Subarachnoid space
How do you tell a TB meningitis?
More lymphocytes
What is aseptic meningitis?
Sterile
Misnomer
Viral meningitis
Less likely to see neck sore
when do you see aseptic meningitis?
First year of life
What is the most common viral cause of meningitis?
Enterovirus (RNA virus)
Coxaky, echo
More common in fall
What are characteristics of enterovirus/picornavirus?
Summer and fall Pico for "small" and "RNA" Transmitted orally or fecally (+) sense RNA Icosahedral capsid No envelope
What type of symptoms are associated with septic meningitis?
Acute
Neurological function
What are some treatment for septic meningitis?
Vancomycin (MRSA)
Acyclovir (HSV-2)
Cefepine (pseudomonas)
Ampicillin (listeria)
What are the big three bacterial meningitis organisms?
Streptococcus pneumonia
Neisseria meningiditis
Hemophilus influenza type b
What etiology for septic meningitis is most common in adults?
Streptococcus pneumonia (75%)
What etiology is most common is 11-17 year olds?
Neisseria meningitiditis
What is the vaccine recommended for all adults over 65 for septic meningitis?
13 valent pneumococcal conjugate vaccine
What is the development of meningitis by the 3 most common bacteria?
- Mucosal colonization at nasopharynx
- Invasion and multiplication on bloodstream
3,4. Cross BBB into CSF - Release of inflammatory cytokines in CSF by Microglia and astrocytes
- Subsequent increased permeability of the BBB
- Diapedesis of leukocytes into CSF
- Edema and increased intracranial pressure
- Neuronal injury including hearing loss (CN VIII)
What virulence factors are common in all three major bacteria for septic meningitis?
Capsule
IgA protease
What are the major virulence factors for Neisseria Meningitiditis?
Capsule IgA protease Pili (attachment to mucosa) Endotoxin (gram neg) Outer membrane proteins (gram neg) (Gram negative bacteria)
What are the major virulence factors for Haemophilus influenza?
Capsule IgA protease Pili Endotoxin Outer membrane proteins (Gram neg)
What are the virulence factors for streptococcus pneumonia?
Capsule
IgA protease
(Gram positive bacteria)
What is the Endotoxin form gram negative bacteria?
LPS
What is the Endotoxin in Neisseria meningiditides?
LOS lipooligosaccharide
Why are endotoxins illusive?
They mimic brain sphingolipids
What is LPS mode of action?
Activate macrophages leading to release of NO
And IL-1 (fever) and can activate coagulation leading to purpuric skin
Therefore if you have rash you should be thinking less of strep
What does interleukin 1 do?
Fever
What is the capsule of meningitis bacteria composed of?
Acidic polysaccharides which prevents phagocytosis by PMN Granulocytes
What is S. Pneumonia transmitted by?
Respiratory droplets
What is meningitis secondary to when caused by S. Pneumonia?
Paranasal sinusitis and otitis media
What is the most common cause of septic meningitis in ages older than 2months?
Streptococcus pneumonia
What does strep pneumonia look like under a microscope?
Coccus Purple (gram positive) Usually in chains but can be singlets and doublets Diplococci Lancet shape
What is the most resistant type of strep pneumonia and what is the treatment?
19A-resistant
Treated with vancomycin
What is used to identify strep pneumonia serotype?
quelling (capsular swelling in response antiserum)
What is the most common cause of septic meningitis in infants and young children?
Hemophilus influenze type b
What are characteristics of Hemophilus type b under a microscope?
Grows in chocolate agar with factors V (NAD+) and X (hematin)
Coccoid rod
Phone do you vaccinate against Hemophilus influenza type b?
With Hib vaccine-B capsular polysaccharide
what are TORCH infections?
Perinatal meningitis infections
What is the most common cause of TORCH infections?
GBS - group b strep
What are common causes of perinatal meningitis?
GBS, E. Coli, listeria
What is the antigen the GBS has?
Lancefield group b antigen
How is GBS aka streptococcus agalactiae commonly transmitted and from where?
It is common in the GI tract and genitourinary tract flora
Vertical transmission to intact in utero or from a vaginal birth
What does GBS cause?
Sepsis, pneumonia, and meningitis
What race is GBS most common in?
Twice as common in African American Infants
What is given prophylactically to pregnant women with GBS?
Penicillin G
What are some defining things about GBS?
Bacitracin resistant
Catalase negative
CAMP reaction
What E. coli strain and type cause meningitis and in what age group?
E. coli K1 Gram negative Rod LPS K1 capsular polysaccharide prevents fusion with lysosome Sometimes expresses beta lactamses
What is the treatment for E. coli?
Ceftriaxone
If beta lactamses present use carbapenem
What causes chronic meningitis?
Syphillis
Spirochetes
TB
Fungal (cryptococcis, candida)
What percent of TB cases also have meningitis?
25%
What drugs are used against TB?
Isoniazid - inhibits mycolic acids, acetylation by the liver stops the drug sometimes
Rifampin - RNA polymerase, red body fluids, inhibits p450
Ethambutol - cell wall inhib by arabinosyl
Pyrazlinamide - unknown
What is the main fungi cause meningitis?
Cryptococcis neoformans
Use India ink stain
What is the treatment for fungal meningitis?
Liposomal amohitericin B
With flucytosine
Followed by fluconazole for 3-12 months sometimes life
What is amphotericin b?
Binds to ergosterol
Also cholesterol
Neohrotoxic
What is flucytosine?
Similar to 5-fu
Converted to 5-fu in fungi
Narrow, yeast form
Bone marrow suppression
What is the big anti fungal class?
Azoles
Binds fungal p450 and inhibits ergosterol production
Efflux
Fluconazole is the best for CNS penetration
When do you get photophobia?
Aseptic meningitis
What does LPS do?
Causes you to not clot
Lower your platelet counts
What is a normal glucose in the CSF?
40-100
What is E. coli is associated with infants?
E. coli K1
What does Echo virus 9 cause in what age?
Meningitis
Teens
What grows on the chocolate agar?
H. Influenze type b
What is GBS?
Strep agalactiae
What drug is mostly likely to interfere with other drugs?
Rifampin
Inhibits p450
What test might you do do diff between a meningitis and encephalitis caused by a virus?
MRI
Maybe see more red blood cells with encephalitis with necrosis
