Flashcards in Micro: the Syph Deck (19):
What are the microbiological features of treponema pallidum?
outer and inner membranes - endoflagella between
NO gram stain - no LPS
*cannot be cultivated in vitro
syph exclusively human dz
What is important to know about the treponema species in general?
cause disseminated dz - CNS
host immune response responsible for manifestations
cannot be distinguished from pallidum
What is the relationship b/w syphilis and HIV?
genital ulcers increase risk of HIV transmission
What is the basic pathogenesis of syph?
organisms penetrate abraded skin or intact mucus membranes and begins to replicate in dermal tissue -->primary stage chancre when immune cells come in
very invasive - small inoculum establishes dz, and disseminates soon after
What are the clinical manifestations of the primary stage of syph?
3-8 wks incubation
chancre, indurated painless ulcer at site of inoculation - firm, well-demarcated
regress spontaneously but latent w Ab production
How does syph disseminate?
for unknown reason, some escape during primary and home to vasculature endothelium - pass through tight jxns
What are the features of the secondary stage of syph?
w/i 6 months - rash, *mimics other dzs, heaviest bacterial burden = most Abs
also regress spontaneously
What are the outcomes of secondary syph?
1/3 spontaneously cure
1/3 latent for life
1/3 progress to tertiary
What are the features of tertiary syph?
CV (thoracic aortic aneurysm)
Which syphilis pts are or aren't infectious?
soon after inoculation through early latency are
late latent and tertiary usually not
How does congenital syph occur?
transplacental transmission - after 18 wks and women inf for two years or less
How does immunity to syph work?
overlapping acute and chronic inflammation account for majority of symptoms of all stages
membrane lipoproteins on organsim main proinflammatory mediators*
strong Ab response - but NO protective immunity - major immunogens not on outer surface
How is diagnosis of syph done?
dark field microscopy - primary, secondary, some early congenital lesions/exudates
nonspecific then specific serologies - all stages
What are the nonspecific serologies for syph?
VDRL or RPR measure anti-cardiolipin Abs
good for tracking dz progression/response to therapy since specific Abs don't fall
What are the specific serologies for syph?
reactive denote present or past inf - remain + for life
if negative, VRDL was false +
+ means you must treat - can't tell past from active
How can spirochetes be observed on biopsy?
usually lymphocytic infiltrate w plasma cells
How can congenital syph be diagnosed?
routine serologies not helpful because detect moms IgG
detection of fetal IgM can help
What is the treatment for syph?
IM penicillin (tetracycline is alternative)
allergic can be de-sensitized
neurosyph gets high dose, parenteral pen