8. Syphilis Flashcards
What microorganism causes syphilis?
Treponema pallidum
What is syphilis?
- chronic potentially fatal infection
- spread through sex, intravenous drugs and is congenital
- origin is controversial
- Columbian, Pre-Columbian and Evolutionary theory
What microorganism causes the Pinta disease?
- Treponema carateum
- spread by direct skin contact (CEntra; -South America)
- manifestations; skin lesions, scarring, disfigurement
What microorganism causes the Bejel disease?
- Treponema pallidum Subsp. endemicum
- spread by; contaminated eating utensils (Africa/ Asia)
- manifestations; oral lesions
What microorganism causes the Yaws disease?
- Treponema pallidum Subsp. pertenue
- spread by direct skin contact; (S. America/ Asia/ Africa)
- manifestations; skin lesions destruction of lymph nodes/ bones
What microorganism causes the Syphilis disease?
- Treponema pallidum Subsp. pallidum
- spread; sexual/ congenital
- manifestations; primary - tertiary syphilis
What is the epidemiology of syphilis?
steady increases:
- behavioural changes; alcohol, drugs, promiscuity, MSM (78.4%)
- Associated with large outbreaks
- unprotected oral sex
- social venues/ networks
What is primary syphilis?
- infectious dose; 50-100
- 3 weeks (10-90 days); single painless ulcer (chancre); highly infectious
- widespread dissemination
- lymphadenopathy
- often inconspicuous (MSM)
- chancres heal spontaneously (2-6 weeks)
What are clinical manifestations of primary syphilis?
- incubation period; 10-90 days post contact
- genital chancre; painless sore
- lymphadenopathy
- spontaneous healing - 2-6 weeks
What is secondary syphilis?
- widespread dissemination
- symptoms appear in approx 3 months
- non-specific and specific presentation
- specific; disseminated mucocutaneous rash; alopecia; condyloma late (infectious lesions)
What are the clinical manifestations of secondary syphilis?
- incubation period; 6weeks-6months post contact
- non-specific
- specific symptoms; mucocutaneous rash, lymphadenopathy, alopecia, condyloma lata
What is tertiary syphilis?
- 20-40 years after initial exposure
- widespread progressive/ chronic inflammation leading to:
- gumma (nodular-like lesions)
- cardiovascular syphilis (aortic aneurysm)
- Neurosyphilis, tabes dorsalis
What are the clinical manifestations of tertiary syphilis?
- most destructive form of syphilis
- granulomatous lesions
- cardiovascular syphilis
- neurosyphilis; paresis, tabes dorsalis
What is congenital syphilis?
early onset (2-10 weeks post-delivery);
- sniffles
- skin lesions
- pulmonary haemorrhage/ hepatitis
late onset (>2 years);
- Hutchinson’s teeth - central incisors notched
- saddle nose
What is the physiology and structure of Treponema pallidum?
- 0.1micrometres - 6-15micrometres
- 3 periplasmic flagella; corkscrew motility
- limited metabolic capacity; glycolysis, but no TCA - host-derived: difficult to grow
- unculturable on artificial media
- slow doubling time (30h)
- sensitive
What are the virulence factors?
- attachment;
Tp0115 binds to matrix fibrinogen
Tp0483 binds to both matrix and soluble fibronectin - invasion;
hyaluronidase production / molecular mimicry - motility; corkscrew motion
- chemotaxis; Methyl-accepting chemotactic proteins/ Cytoplasmic chemotactic proteins
What is the clinical diagnosis of syphilis?
complicated
- chancre often inconspicuous
- syphilis; ‘great imitator’
What is the laboratory diagnosis of syphilis?
- conforms/disproves clinical suspicion (patient history required)
- Treponema; non-culturable on artificial media
- usage of direct microscopy and serological assays
How can syphilis be diagnosed via clinical samples?
- painless/ asymptomatic
- exudate from penile chancre (primary) or condylama lata (secondary)
How can syphilis be diagnosed via dark-ground microscopy?
- DGM: paraboloid condenser
- light scattered by motile treponemes
- bright treponemes against a dark backgroung; slow, corkscrew- like motility
How can syphilis be diagnosed via results interpretation?
- positive result; primary/secondary syphilis
- negative result; does not rule out syphilis
How can serological assays be used for diagnosis of syphilis?
- estimation of IgM/ IgG antibodies
- non-specific and specific antibodies produced in syphilis infection; both exploited in serological analysis
a) non - specific (reagin) antibodies:
cardiolipin/ cholesterol
b) specific antibodies:
flagella proteins, surface lipids
What clinical samples can be used for serological analysis?
serum
CSF: neurosyphilis
Foetal blood cord: congenital syphilis
What is a non-specific serological assay?
VDRL test - venereal disease reference laboratory
- detects non-specific antibody to cardiolipin/ cholesterol/ lecithin agent
sensitivity: primary (78%), secondary (100%), tertiary (71%)
specificity: 98%
BFPs: autoimmune disease, connective tissue disorders, viral infection, coronary artery disease
