Syphilis Flashcards
How would you classify the bacterial morphology of treponema pallidum subspecies pallidum
gram negative spirochete bacteria
What is the name of the bacteria that causes syphilis
treponema pallidum subspecies pallidum
how can syphilis be transmitted
direct contact with an infected lesion i.e. sexual
vertical (most commonly transplacental spread in utero)
infected blood products
sharing of infected needles
what is the transmission rate of syphilis to sexual partners
up to a third of sexual partners will develop the infection
what stages of syphilis are more likely to cause in utero (transplacental) spread to the foetus?
early syphilis much more likely to transmit to baby in utero (i.e. primary or secondary syphilis, infection for < 2 years, when RPR > 8)
how do we define early and late syphilis
early < 2 years and late > 2 years
what are the three stages of syphilis and can you describe typical features
primary syphilis: incubation period 9-90 days (typically 21 days), primary papule (chancre) and regional lymphadenopathy
secondary syphilis: 4-10 weeks after initial chancre developed, multi-system involvement - maculopapular rash inv palms and soles classically, alopecia, oral snail track ulcers, condylomata lata (warty growths in warm, moist areas perianal common), generalised lymphadenopathy. can also cause hepatitis/splenomegaly, glomerulonephritis and 1-2% will develop meningitis presentation or cranial nerve involvement - neurological syphilis
tertiary syphilis: occurs years after 20-40 years after initial infection
1. Gummatous - skin lesions
2. cardiovascular - aortitis, aortic regurgitation
3. neurological involvement: general paresis (dementia) or dorsal column involvement or meningovascular syphilis
what proportion of patients if not treated at the stage of primary syphilis infection will go on to develop secondary syphilis
a) 10%
b) 20%
c) 25%
d) 50%
c) 25%
if secondary syphilis is not treated it will resolve and go into which phase of syphilis
asymptomatic latent phase (defined as early < 2 years or late > 2 years)
what proportion of patients with untreated syphilis go on to develop tertiary syphilis?
a) 1/4
b) 1/3
c) 1/2
d) 3/4
b) 1/3
how can neurosyphilis present in terms of secondary stage of disease
meningitis - neck pain, photophobia, headaches etc
cranial nerve palsies - often affecting optic nerve (CN II) and vestibulocochlear (CN VIII)
what are the signs of neurosyphilis in late tertiary syphilis
- general paresis - cognitive decline e.g. dementia
- Meningovascular - infective infarcts, vasculitis
- Tabes dorsalis - inflammation of dorsal column (loss of vibration sense, areflexia, loss of joint position) - argyll robertson pupil, sensory ataxia
what would you find on examination if argyll robertson pupil?
pupil does not constrict to light but constricts to accomodation
sign of tertiary neuro syphilis
How do we classify congenital syphilis
early (< 2 years old) and late > 2 years old
what are some of the signs of late congenital syphilis
hutchinson’s incisors (notched teeth)
mulberry molars
clutton’s joints (bilateral joint swelling classically knees)
sensineural deafness,
saddlenose deformity
frontal bossing
what are some of the signs of early congenital syphilis
bloody snuffles ( haemorrhagic rhinitis)
rash
generalised lymphadenopathy
hepatosplenomegaly
skeletal abnormalities
what tests can we do to identify t. pallidum direct from genital chancres
dark ground microscopy - identify the spirochete
PCR swab
what sites can you not perform dark ground microscopy on lesions when ? syphilis
not suitable for oral lesions due to commensals - but can do oral PCR in these situations
can you use a syphilis PCR swab on oral lesions
yes
how do we classify syphilis serological tests
specific to t. pallidum
non specific to t. pallidum
can syphilis antibody tests distinguish between syphilis and endemic treponemes
no all tests will be positive for treponemal pallidum (e.g. can’t distinguish pallidum subspecies between yaws/ pinta/ bejel)
can you name the specific antibody treponemal tests
EIA
CLIA
TPPA
TPHA - Treponema pallidum
t.pallidum EIA IgM
(most of these test IgG and IgM)
can you name the non-specific antibody treponemal tests
RPR
VDRL
these measure disease activity
what type of syphilis tests act as the screening test for syphilis
treponemal specific antibody tests (in sheff we use EIA IgG)e.g. CLIA, EIA or TPHA (no longer use TPPA)
ideally tests that combine IgG and IgM
what is the main issue with EIA IgM
only use in primary syphilis, limited by its suboptimal sensitivity
if you get a positive screening test what is the next step
confirm it with an secondary test ideally a different type of treponemal specific antibody test
Does a negative anti-treponemal IgM exclude active infection
no
if treating a patient for syphilis which test the first or confirmatory (second) test RPR or VDRL should be used to measure treatment response
second confirmatory VDRL or RPR should be used as your baseline
Answer true and false:-
- RPR/VDRL is used as a marker of disease activity
- an RPR > 16 suggests active infection
- EIA is a specific treponemal antibody test
- Repeat syphilis serology should be performed at 2 weeks if symptoms e.g. chancre suggestive of syphilis and initial tests negative
- IgG antibodies can pass in utero
- true
- true
- true
- true
- True
what time scale is recommended to repeat syphilis serology following a single high risk exposure
6 and 12 weeks
how long can syphilis tests be negative for once someone has developed a chancre
for up to two weeks after chancre develops
which test can you develop a prozone phenomenon and can you explain what it is
false negative test result in RPR/VDRL tests. It is due to high antibody titres which interfere with antigen-antibody lattice necessary to produce a positive test in UNDILATED samples. The serum needs to be dilated more to produce the reaction to be seen. Can be more likely to occur if co-infected with HIV.
what situations can you get a false positive syphilis serology
auto-immune disease
elderly
pregnancy
injecting drug use
when should you consider performing an LP to examine CSF to look for syphilis
failure to get a four fold decrease in RPR following treatment
neurological symptoms suggestive of neurosyphilis
true or false: RPR is less sensitive than VDRL in csf testing
true
how can you diagnose early CS in infants
dark ground or syphilis PCR of ulcers/ subicious lesions with exudate
serological blood tests - need to be done of the infant and not the cord
if an infants serological blood tests are positive for EIA IgG does this confirm CS?
no - baby can receive IgG antibodies passive transfer in utero across the placenta. Need to check for EIA IgM and RPR/VDRL of the infants blood not the cord.
Can take up to 18 months for IgG EIA antibodies to disappear in infant blood tests
what are some of the serological markers in an infant of CS
EIA IgM positive
VDRL/RPR four fold greater than that of mum’s
positive VDRL/RPR on csf
positive EIA (or treponemal antibody tests - CLIA/TTP/TPHA) IgG > 18 months
what is the general advice to patients Rx for syphilis in terms of sex
Minimum no sex for 2 weeks and until lesions have fully healed and they and partners have completed Rx.
Risk of transmission in late syphilis is very rare as disease not active.
what reaction should you warn patients about when treating syphilis
JH reaction - due to antibiotics causing an inflammatory response, temporary - rigors, fevers - self limiting
what class of antibiotics is more effective at Rx syphilis
penicillin
what class of antibiotics is least effective at Rx syphilis
macrolides - specifically erythromycin less effective than
is someone is allergic to penicillin what should you consider
penicillin desensitisation
what is first line Rx for early/ primary/ secondary syphilis in non pregnant patient
benzathine penicillin 2.4MU IM stat dose
how does Rx for primary/secondary/ early syphilis in pregnant women change
only changes if Rx during third trimester - two doses 7 days apart of benzathine penicillin 2.4MU IM day 0 and day 7.
need to warn re JH reaction - can cause uterine contractions and fetal decels usually self resolves and no adverse outcomes to foetus but consider discussing with obs if concerns
routine use of steroids to prevent the JH reaction is NOT recommended
benzathine penicillin or procaine penicillin could be given IV if not tolerating IM route?
no - only benzylpenicillin can be given IV
prior to treating cardiovascular and neuro syphilis with antibiotics what should be given first and why
start steroids usually prednisolone 40-60mg OD for three days, start 24 hours before starting abx this is to prevent an inflammatory response
penicillin for the treatment of syphilis is licenced?
no - unlicensed.
maternal non treponemal antibodies e.g. RPR or VDRL should be negative in the neonate by what time frame?
3 months
6 months
12 months
18 months
6 months
passively transferred maternal treponemal antibodies e.g. EIA IgG should be negative in the neonate by what time?
3 months
6 months
12 months
18 months
18 months
what tests do babies born to mothers rx for syphilis during pregnancy require
bloods tests including EIA IgM, RPR/VDRL at 3 months and then three monthly until negative
what are the recommended treatment regimes for epidemiogical treatment or potentially incubating syphilis
1st line: benzathine penicillin 2.4MU IM stat (1C)
second line: doxycyline 100mg BD, PO 14 days (1C)
third line: azithromycin 2g PO, stat (2c)
what are the alternative regimes for early syphilis if penicillin not suitable
- procaine penicillin G 600,000 units IM OD for 10 days
- Doxycyline 100mg BD 14 days PO
- ceftriaxone 500mg IM OD 10 days
- amoxicillin 500mg PO, QDS + probenacid 500mg QDS for 14 days
- erythromycin 500mg QDS, PO, 14 days (2b)
- azithromycin 2g stat PO or 500mg OD for 10 days (2b)
what is the treatment for late latent, cardio or gummatous syphilis
Benzathine penicillin 2.4MU three doses IM weekly.
pre cardio Rx start prednisolone 40-60mg OD three days, start 24 hours before starting antibiotics.
what are the alternative treatment for late latent, cardio or gummatous syphilis if benzathine penicillin not suitable
- amoxicillin 2g TDS PO + probenacid 500mg QDS PO for 28 days
- Doxycyline 100mg BD 28 days
what are the two options for treatment of neuro syphilis
pre antibiotics start 24 hours before abx start pred 40-60mg OD for three days in total
abx:
1. Procaine penicillin 1.8-2.4 MU IM 14 days + probenacid 500mg QDS PO 14 days
2. Benzylpenicillin 1.8-2.4g IV every 4 hours for 14 days
what are the alternative treatment options for neuro syphilis if procain and benzylpenicillin unsuitable
- doxycyline 200mg BD 28 days
- amoxicillin 2g PO TDS + probenacid 500mg QDS 28 days
- ceftriaxone 2g IM or IV for 10-14 days
obv still using steroids pre abx
when can a procaine reaction occur
accidental injection of procaine penicillin IV rather than IM
short lived - psychosis, fear of imending doom, seizures - symptoms settle after 20 mins
what is the lookback period for PN in primary syphilis
90 days
lookback period for PN in early syphilis
2 years
look back period in late syphilis
> 2 years,
are individuals with late latent syphilis able to transmit the virus to partners
no
what is the recommended follow up for patients treated for syphilis and what are we aiming for
blood tests - RPR/VDRL at 3 months, 6 months, 12 months
looking for RPR or VDRL to become negative or neat or a four fold decrease in RPR within 12 months
how do you classify treatment failure
failure for a four fold decrease in RPR in 12 months
if RPR/VDRL fails to fall by four fold in 12 months what should you consider next steps for this patient
consider re-treatment and examination investigation for neuro syphilis with CT head + LP.
if re-treating then would cover for late syphilis with three doses of IM benzathine pencillin 2.4MU IM for 3 doses over 3 weeks.
