Meningitis and Endocartitis Flashcards
what is endocarditis?
infection of endocardia surface of heart (usually valves)
who is most susceptible to endocarditis?
people with prosthetic valves or other foreign material
what organisms usually cause acute endocarditis?
highly virulent organisms
what is the process of endocarditis?
colonization on skin/mucous membrane
bacteremia in blood (through trauma)
adhere to roughened endocardia surfaces
platelet fibrin deposition
bacterial division
cauliflower vegetations develop (with dormant organisms inside)
what the heart consequences of endocarditis?
impair normal valve functions (eventually destroy)
small emboli can enter arteries and cause myocardial infraction
abscesses may develop in heart muscle that impair electric conduction
what are the brain consequences of endocarditis?
brain cortex showered with micro-emboli = confusion and coma
large emboli can cause stroke or brain abscesses
what other consequences of endocarditis are there?
large emboli can obstruct renal artities
immune complexes may cause renal damage
emboli may go to spleen, extremities, eyes, other organs
involved blood vessels will weaken stretch and burst
what are common pathogens that cause endocarditis?
high virulence = S. aureus, S. pneumonia
low virulence = viridans, streptococci species
how is endocarditis diagnosed?
risk factors (surgeries, heart disease, IVDU, indwelling caths)
blood cultures
echo (to see vegetation)
how is endocarditis treated?
combination antibiotics for at least four weeks
how is endocarditis prevented?
prophylactic antibiotics for surgery
what is meningitis?
inflammation of membranes covering brain and spinal cord
what are the types of meningitis?
acute or chronic (rare - can complicate preexisting conditions
what bacteria is meningitis caused by?
strep pneumo
neissaria meningitis
h. influenzae
listeria monocyogens
what viruses can cause meningitis?
enteroviruses (usually mild during summer)
arboviruses (areas with mosquitos)
who does strep pneumo meng effect?
children and adults
doesn’t cause outbreaks
who does neisarria meng effect?
mostly infants, children teens
sporadic and outbreaks
vaccine!!!!
who does h influenzae meng effect?
3 months to 5 years
vaccine!!!!
who does listeria meng effect?
the very young and very old
most related to food
outbreaks may occur
how does meng invade the body?
nasopharyngeal colonization, local invasion, bacteremia, meningeal invasion, bacterial replication and release
how does the body respond to meng?
activation of macrophages to release cytokines
subarachnoid space inflammation
increased CSF outflow resistance
cerebral vasculitis
increased blood-brain permeability
increased brain edema
confusion
coma
how is meng diagnosed?
clinical features
CT scan
cerebral spinal fluid
gram stain
CSF culture
PCR
how is meng treated empirically?
empirically - ceftriaxone/vancomycin and ampicillin
how is strep pneumo meng treated?
vancomycin
