Micro: the Syph Flashcards Preview

Block 8 - Endo & Repro > Micro: the Syph > Flashcards

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?

benign gunnas
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
no vaccine


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?

silver stain
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


What is an important side effect of treatment for syph?

Jarish-Herxheimer rxn - during therapy of primary or secondary = w/i several hours, due to release of large amounts of bacterial constituents as they die in mass and provoke cytokine cascade (give TNFalpha)
sudden fever, flushing, tachycardia, vasomotor instability