Syphillis Flashcards
What causes the syphilis infection
Treponema pallidum spirochetegram negative bacteria Obligate parasite
Transmission
- Acquired: Sexual contact (enters through breaks in the skin) contaminated needles / Direct lesions
- Congenital: (in utero or at delivery)
How does primary syphilis present
Primary syph is 1-3 weeks after exposure to infection, syphilitic chancre (painless classically but actually half are painful)
Be solitary or multiple (approximately one third reported as multiple)
Hard base, raised borders, fluid rich in spirochetes,
Chancre can be around external genitialia but if through contact can occur anywhere
Chance will heal on its on over months - can have associated lymphadenopathy
(if through blood may not be )
HIGH risk fetal infection
What occurs in secondary syph
Secondary 6-12 weeks after infections - spirochetaemia - Generalised lymphadenopathy
Can affect endothelial cells - causing non itchy maculopapular rash - trunk then travels to palms, soles, Can be pustular or papulosquamous
Can be condyloma lata wart like (smooth white painless gentials, anal, armpits)
Secondary syph is most infectious - lasts weeks to months
Can have constitutional sx
Latent phase - Disease - dormant / asymptomatic - stored in organs
Early phase - within a year, spirochetes can reenter the blood - can have sx of secondary syph
Late phase - after 1 year - will stay within organs
MODERATE rate of fetal infection
If untreated 40% progress to tertiary infection
What is Tertiary Syphilis, what happens
1/3 of untreated populations
Type 4 hypersensitive reaction, immune reaction with T cells, pro inflammatory phagocytes and cytokines TNF IL 1 IL 6 leading to Redness warmth systemic sx like fever
Antigen on T Pallidum : group specific antigen
Species specific antigen
Cardiolipid (within spirochetes and cells in our body)
Granulomatous lesions - Gumma - immune cells surrounded by fibroblasts - often no spirochetes in there, Can necrose
Teritiary syph - cardiovascular - endarteritis (inflammatory of the vessels)
Brain and spinal cord - loss posterior spinal cord - loss of proprioception or vibration
Or anterior cord - paralysis
Liver joints and testes
Negligible rate fetal infection
How to test for syphilis
Dark field miroscopy to see spirochetes from chancre
Confirmed with serology
Antibodies against T pallidum - not syph specific
Non treponemal tests Antibodies to non specific antigens (VeRy close)
RPR- rapid plasma reagin test
VDRL- Veneral disease research labarotory test
Reagin Anti cardiolipid antibodies
Low sensitivity in early or late disease
Become negative after successful treatment so can be used to monitor response to treatment
Treponemal tests: (specific Antibodies) (T for T)
TPPA (T Pallidum particle agglutination)
FTA ABS fluorescent treponemal antibody
EIA (Enzyme immunoassays)
TPHA
More specific - positive for years despite treatment
Screening for syph
Population based setting
Booking bloods and repeat 28 weeks
“Traditional algorithm” High prevalence - use non treponemal (VDRL) and confirm with treponemal specific test (TPPA)
If low prevalence setting use treponemal (TPPA) and confirm with non (VDRL) less work and better sensitivity
Pregnancy RPR - should be used / IgG based test (IgM increases false positive results)
Fetal Childhood affects
Early and late
2/3 babies born without sx
Early - IUD jaundice, Hepatosplenomegly, maculopapular rash, palms and soles, pneumonia, coombs negative HA snuffles Mucocutanous lesions of palms and soles peristitis
Later - hutchinsons teeth (notched central teeth) saddle nose, frontal bossing, saber shin deformity, knee synovitis
Hutchinsons triad - hutchinsons teeth, interstitual keratitis, deafness
What is the treatment for syph
– Benzathine penicillin 1.8g (= 2.4 million units) IM, as a single dose OR
Can have jarisch - herxheirmer syndrome - as spirochetes are treated then explode and a large inflammatory reaction is activated
How to interpret tests VDRL + TPPA + VDRL + TPPA - VDRL - TPPA - VDRL - TPPA +
VDRL + TPPA + Syph - needs treatment
VDRL + TPPA - if repeated and same then biologically false positive
VDRL - TPPA - No syph
VDRL - TPPA + Previous treated
How to monitor effectiveness of treatment
Repeat VDRL or RPR monthly until delivery
-ve or >4 fold drop in titre - successful treatment
How to monitor neonatal syph
Infant serology (IgM, RPR to be run in parallel
with maternal serology)
Full clinical examination (rash, mucosal lesions, hepatomegaly,nasal discharge, bony tenderness,
eye lesions)
Placental histo and PCR
Bloods and CSF if any of these are abnormal
Repeat infant serology at 3 and 6 months
Does timing of treatment in pregnancy matter?
Women and their partners who are tested and receive appropriate treatment during the first two trimesters of pregnancy are 2.24 times more likely to have a healthy baby than those receiving syphilis treatment during the third trimester
Is syphilis always symptomatic?
Approximately 50% of women will have no symptoms and will only be diagnosed by serological testing
When does vertical transmission occur?
o Treponema pallidum readily crosses the placenta
o Can occur as early as 9–10 weeks gestation
o Can occur at any stage of disease, including during incubation, although risk is greatest in infectious syphilis
o Can occur several years after initial infection in the untreated woman
o More commonly occurs in the last two trimesters
What is the incubation period for syphilis ?
· Mean incubation 21 days (range 9–90 days) from contact to the development of a chancre
o Larger infectious dose results in earlier ulcers