Flashcards in Syphilis Deck (48):
How is syphilis transmitted and can it survive in the environment for long?
Mainly via sexual contact. Can be transmitted transplacentally (congenital syphilis). The organisms are sensitive to heat, drying, disinfectants and soap therefore only transmitted via close contact.
Syphilis incubation period?
9-90 days (~ 3 weeks)
How does syphilis invade the body?
Penetrate mucous membrane/damaged skin > spread to regional lymphatics > bloodstream > rest of body
Features of primary syphilis?
Chancre - single, infuriated, painless ulcer at inoculation site
Lymphadenopathy - regional lymph nodes
What infection may increase the number or duration of chancres in primary syphilis?
Do all people progress to secondary syphilis?
No, about 1/3 of patients don't progress beyond the primary stage and instead exhibit spontaneous recovery.
What are the features of secondary syphilis?
Snail tract ulcers in mouth
Fever and malaise (most commonly seen)
What is important to note about secondary syphilis?
It is a highly infectious stage.
What are condylomata lata?
They are warty lesions that occur in moist areas eg) scrotum, peri-anal area
How long do lesions of primary and secondary syphilis take to disappear?
What proportion of people progress past secondary syphilis?
2/3 of people will progress to tertiary syphilis.
What are the manifestations of tertiary syphilis?
Benign late syphilis
Characteristics of cardiovascular syphilis?
*endarteritis related to all. Endarteritis is inflammation of the inner lining of an artery.
Features of neurosyphilis?
General paresis of the insane
What is tabes dorsalis?
Slow degeneration of the nerves primarily in the dorsal columns of the spinal cord = Loss of motor control.
What is general paresis of the insane?
Degenerative changes to the brain parenchyma lead to personality change and dementia.
What are the characteristics of benign late syphilis?
Formation of gummas
*usually seen in HIV-positive people
What is a gumma?
Destructive granulomatous lesions in bones, skin, joints and mucous membranes.
How long does tertiary syphilis characteristics take to manifest?
What is latent syphilis?
When a patient appears clinically well (asymptomatic) but is still infected with T. Pallidum
When does latent syphilis occur?
Between secondary and tertiary syphilis.
An important characteristic of latent syphilis?
Infectiousness declines over time.
What can untreated congenital syphilis lead to?
Early congenital syphilis
Late congenital syphilis
Features of early congenital syphilis?
Features of secondary syphilis:
- skin + mm lesions ( Maculopapular rash and condylomata lata)
- generalized lymphadenopathy
- profuse nasal discharge
- failure to thrive
- bone lesions > reluctant to move limb
When does early congenital syphilis occur?
Normally in first few months of life. Can occur at birth.
Is congenital syphilis preventable?
Yes, through screening and treatment of pregnant women.
When does late congenital syphilis occur?
Later in childhood (>5 years) and even in adulthood.
What are the features of late congenital syphilis?
Similar to features of tertiary syphilis:
- gumma formation
- CV syphilis
- 8th nerve deafness
- Hutchinson teeth
What are Hutchinson teeth?
Smaller, wider teeth notches on the biting surface. Is a feature of late congenital syphilis.
Explain why completely eradicating a syphilis infection early will leave the patient vulnerable to re-infection?
In the later stages of secondary syphilis immunity is expressed but immunity is incomplete. IMMUNITY IS MORE EFFECTIVE THE LONGER THE INFECTION REMAINS UNTREATED. Therefore early treatment results in resistence to re-infection rapidly disappearing.
What are the two types of serological tests for syphilis?
Non - treponemal tests
What do non - treponemal tests test for?
They test for the antibody to cardiolipin.
What is cardiolipin?
Cardiolipin is a phospholipid present in mammalian mitochondria.
What are the two types of non-treponemal tests?
RPR (rapid plasma reagin)
VDLR (venereal disease research laboratory tests)
Anti-cardiolipin tests are non-specific. What does that mean?
That they can result in false positives.
At what time can non-treponemal tests for syphilis become positive?
4-6 weeks after infection.
75% in primary syphilis
>99% in secondary syphilis
TESTS USUALLY BECOME NEGATIVE BY TERTIARY SYPHILIS.
In what instances can non-treponemal tests lead to false positives?
Can occur in healthy people.
What do treponemal tests test for?
Antibodies to T. Pallidum
What are non-treponemal tests particularly useful for?
Monitoring the effectiveness of treatment as the test becomes negative if medication successful.
What are the two treponemal tests?
TPHA (T. Pallidum harm agglutination test)
FTA-ABS (fluorescent treponemal antibody test- absorbed)
How does the FTA-ABS (flourescent treponemal antibody test - absorbed) work?
1- non-pathogenic treponemal antigen removed
2- serum then added to a slide fixed with T. Pallidum
3- flourescent anti human immunoglobulin added
What is the "reverse sequence algorithm"?
Where a treponemal test is done is done to assess infection status. Then, a non-treponemal test is done to determine disease activity.
Advantages of the "reverse algorithm" ?
Higher sensitivity in detecting primary and secondary syphilis.
Avoid biological false positives.
Avoid false negatives due to pro zone phenomenon.
What is the pro zone phenomenon?
It is a false negative response resulting from a high antibody titter which interferes with formation of antigen-antibody lattice, necessary to visualize a positive flocculation test.
How to diagnose congenital syphilis?
Modify the FTA-ABS(flourescent treponemal antibody test - absorbed) to detect IgM instead of IgG as IgG is transferred transplacentally. The test may not be very sensitive or specific as newborns may not produce antibodies. Therefore one must rely on non-treponemal tests and monitor changes over time. Passively transferred antibodies should disappear by 6 months.
Drugs used to treat syphilis?
What second-line drugs are used to treat syphilis?
Doxycycline and erythromycin for primary, secondary and latent syphilis. (15-30 days)
Cephtriaxone for tertiary syphilis.
High failure rates for cephtriaxone and erythromycin.