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75 Cards in this Set
- Front
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infx of the CNS
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meningitis, encephalitis, brain abscess
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virchows robins spaces
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perivscular spaces in the brain that contai lymphocytes and macrophages that help to protect
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down side to brains on defenses?
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doesn't allow for expansion when inflammatio occurs, and it hard to get help to the area (immune defenses and abx)
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steps to meningitis?
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mucosal colonization>blood stream invasion>BBB penetration>mult in CSF
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common characteristics of meningitis?
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neurotropism, encapsulation, IgA protease, pili
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most common way for microbe to enter the brain?
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hematogenous
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types of hematogenous spread?
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heavy bacterial load enters resp tract (strep, N men), bites, transplacentally
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how do microbes cross the BBB?
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strep pneumo/N men: loosen the tight junctions
H influ: endocytosis at jnct Grp B strep: produce hyaluaronidase |
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what pathway is important to providing some defense once microbe is in brain?
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alternate pathway
sickle cell and splenectomy can inhibit this |
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bacteria assoc with meningitis?
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S pneumo, N menin, H influ
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which bacteria is assoc with newborns vs adults vs elderly?
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newborn: grp B, e coli, listeria
adults: s pneumo, N men elderly: s pneumo, listeria |
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most common time in life for ppl to get meningitis? Why?
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6 mo - 2 yrs because this is the time you are losing the fetal ab and gaining new ones
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microbes of summer, fall, winter
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summer: arbovirus
fall: enterovirus winter: bacterial |
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characteristics of s pneumo?
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gram +, diplococi, encapsulated, techoic acid (inflammation)
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which antigenic type of H influ is most commonly linked to meningitis?
commonly found? |
B
in URIs |
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virulence factors of H influ?
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encapsulated, pili
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carrier rates of N men?
serogrp typing? |
high levels, nasopharynx (moist, high CO2)
ABC W135 Y |
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virulence factors of N men?
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capsule, LPS (endotoxin), pili, IgA protease
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Common viral pathogens of meningitis?
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enterovirus (non-enveloped, 85-90% infants)
arbovirus: mosquito bite west nile>progress to encephalopathy in elderly |
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microbes associated with traumatic direct innoculation of meningits?
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s pneumo (CSF fistula from sinuses)
e coli, kleibsiella, pseudomonas (penetration) |
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what causes inflammation in meningitis?
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LPS ; H influ, N men
techoic acid: s pneumo |
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most common causes of brain abscess?
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dental abscess, mild ear infection, sinusitis
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common organisms in brain abscess?
organisms in immunocompromised? |
s aureus, grp A strep. usually polymicrobial
crytococcus, toxoplasma |
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causes of encephalitis?
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HSV, arbovirus, enterovirus
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where does HSV lye dormant?
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CN V, and infects frontal and mporal sinus
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who does encephalitis commonly affect?
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used to be kids but now its predominantly older adults
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top 4 bacteria of meninigits?
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s pneumo, N men, listeria, H influ
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distinguishing causitive organisms?
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s pneumo: pneumonia, splenectomy, head trauma,
N men: young adults, complement defect, prior viral URI Listeria: elderly, immunocomp grp B: neonates |
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classic triad of meningitis?
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fever, mental status changes, meningeal irritation (nuccal rigidity, kerigs and brudzinski sign)
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acute vs sunacute meningitis?
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acute: sudden onset, 24 hrs, seizure, mental status changes, neuro signs
subacute: over 1-7 days |
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subacute lumbar puncture picture?
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CSF cultures 80% +, gram stain 60-90% +, complete: protein and glucose exceed 40, WBC exceed 100
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factors that will increase a risk herniation?
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age, immuno-comp, CNS dz, seizure recently
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slide 49***
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???
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if there is a risk of herniation what should you do?
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check for papilledema, mental status changes, and focal deficits
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if pt has acute presentation what should u do?
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stat LP, or at least blood culture and treat empirically
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treatment algorythm for menigitis?
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slide 51
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tx principles for meningitis?
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dont delay, bacteriocidal, high concentration, IV
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empiric IV tx of meningitis?
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3rd gen cephalosporin add vanco for s pneumo resistance
use steroids if pneumococcal infx suspected NOT for N men |
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gram stain guided tx?
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s pneumo: ceftriaxone + vanco (14 days)
H influ: ceftriaxone (7 days) N men: penicillin G (7 days) Listeria: ampicillin + gentamycin |
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hallmark of meningitis?
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sepsis and rash
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who should u suspect?
meningococcal prophylaxis? |
young, hospital worker, close quart, late winter early sprng
within 14 days of prior contact rifampin: every 12 hrs for 2 days ciproflaxicon:once po ceftriaxone: once im |
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who should have meningitis vaccine?
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adolescents (age 11) with booster at 16
college freshmen and military recruits 55+ (use MPSV4) at risk kids: comp deficiency and asplenia |
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aseptic meningitis
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happens in summer, no bacteria on gram stain
enterovirus and arbovirus |
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encephalitis and meningitis overlapping themes?
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inflammation, fever, A LOC, focal neuro findings
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slide 63
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???
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3 esential steps for encepalitis?
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brain MRI for all pt
acyclovir for anyone u suspect meningitis in shift to specific tx once etiology known (etiology unknown in up 75% of pt) |
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where does endocarditis happen?
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valves, chordae tendinae, endocardium, chamber walls
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who is at risk of endocarditis?
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IV drug users, ppl with replacement valves
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which type of endocarditis is more common?
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subacute: it is less virulent and attacks abnormal tissue, occurs in >6 weeks
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tricuspid valve is usually infected by which organism?
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staph aureus
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organisms of endocarditis?
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strep viridans (dental work)
enterococcus feacalis (GI/GU maniplation) |
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other organisms?
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staph epidermidis, strep pneumo
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native valve vs prosthetic valve microbes?
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N: strep viridans, pneumo, staph aureus
Pros: staph aureas and epidermidis |
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2 most commonly effected valves?
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Mitral and aortic
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if bacterial release is transient what does that mean?
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your going to need multiple cultures from multiple sites
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venturi effect?
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how bacteria takes hold in high flow areas, there is generally a low flow to the sides
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body protection turned bad?
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platelet and fibrin mesh that may normally help other infections give the bacteria a place to hide from other defenses of the host. can lie dormant and then break off causing infection in other areas. Techoic acid (entero) and FimA (strep viridans) help with the attachment
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what can strep produce that allows it to attach?
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dextran, mostly strep mutans
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which organisms produce fibronectin?
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staph aureus, enterococcus, strep
allows for attachment to fibrin |
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what factors help microbe resistant complement cascade?
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capsules (strep p) and sialic acid
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what causes constitutional symptoms and valvular dysfunction in endocarditis?
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cytokines
infx of the valve |
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25 -35% of endocarditis pts have these and 45-65% of them die from it?
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emboli
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mitral vs tricuspid down stream problems?
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m: kidney and vital organs
t: pneumonia, lung abscess |
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immune complex found on hands in endocardtis?
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osler nodes and janeway lesions
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infective endocarditis occurence in?
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rheumatic fever (uncommon), increased age, pros valves, IV drug use
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two most common causes of native valve endo?
prosthetic valves? |
strep viridans and staphaureas
staph aureas, staph epider |
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what does the clincal picture result from in endocarditis?
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infectious process on valves, septic emboli, bacteremia, circulating immune complex
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clinical finding in subacute bacterial endo?
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insidious onset of constitutional symptoms
murmurs bacteremia ocular findings splenic and renal manifestations |
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clinical picture in acute bacterial endo?
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abrupt onset, high fever, rigors prominent cutaneous symptoms
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Dx testing for endo?
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3 cultures over 24 hrs
TEE |
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Tx for various causes?
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strep: penicillin G + gentamycin for 2 weeks
entero: same as above 4-6 weeks staph: nafcillin, vanco if mrsa HACEK: ceftriaxone |
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if abx not working?
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surgical debridment
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which pt might expect abx but u won't give them it?
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mitral valve prolapse, rheumatic hrt dz, bicuspid valve, aortic stenosis, congenital hrt condition
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events increasing risk of endo?
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dental procedure, resp procedure
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prophylaxis
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amoxicllin 2g PO 1 hr prior to dental procedure
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