Symphilis Flashcards
Definition / Risk factor
Syphilis is a systemic infection caused by the gram -ve spirochete (Treponema pallidum)
Aetiology – sexual contact, blood-borne, or vertical
- Risk factors – young (age <29 years), African American, use of illicit drugs, infection with other STIs, sex worker
Incubation period: 10 - 90 days (average 21 days)
Signs and symptoms
Primary (3-4w)
- painless chancres (typically singular) ± local lymphadenopathy (this is your local response to the bacteria)
Resolves in 3-8w
Secondary (4-10w after chancre)
- only 25% get symptoms…
- Resolves spontaneously in 2-12w
- Rough papulonodular rash (hands, feet, trunk)
- 1-2% have neuro complications like acute meningitis, CN palsies (hearing loss, uveitis)
- Condylomata Lata
- Lymphadenopathy + systemic symptoms
- “Snail track oral ulcer”
Latent (no symptoms; detected on routine tests - Positive serology but no signs of infection) – guides management:
- Early latent (<2 year after infection – exposure to OR symptoms of 1st/2nd in <2 year)
- Late latent (>2 year after infection – exposure to OR symptoms of 1st/2nd in >2 year)
- Really important to check and have this as a differential as syphilis can be latent and present after a few years even as PR bleeding and pus discharge eso before colonoscopy as that can cause spreading
Tertiary (1 to 20 years) – affects 1/3rd of untreated illness:
- Gummatous syphilis / 15% (erosive skin and bone lesions)
- Cardiovascular syphilis / 10% (aortitis, aortic valve regurgitation (early diastolic decrescendo), heart failure)
- Neurosyphilis – types (n.b. tabes dorsalis affects the dorsal columns):
- Meningovascular (5-10 years) à Ischaemia (stroke), insomnia, emotionally labile, headache, tinnitus, optic neuritis
- General paresis (10-25 years) à Dementia (gradual loss of cortical white matter) and cognitive function, personality and hemiparesis
- Tabes dorsalis (15-20 years) à sensory problems, lightning pains, absent reflexes, pupil changes, neuropathic ulcers
Investigations
- Microbiology – dark-ground microscopy (from chancre with dark-field illuminations), PCR if suspected but DGM negative
- Serology – routine antenatal screening offered to all pregnant women à detects treponemal antibodies
- N.B. it takes 3/12 for syphilis to become positive in serology…
- Non-treponemal tests – high false positive rate due to cross-reactivity (i.e. with EBV)
- RPR (rapid plasmin reagin) – dilutional ratios – i.e. how many dilutions to lose the reagin:
Examples:
1: 2 = need to dilute to 1: 2 to lose the reagin (i.e. low levels of reagin)
1: 512 = need to dilute to 1: 512 to lose the reagin (i.e. high levels)
N.B. sero-fast = stable ratio 1 either side of each test (i.e. 1: 8, 1: 4, 1: 16 = sero-fast)
- Helps stage infection - typically raised in early infection
- If positive, must be followed up by a more specific treponemal test
- VDRL (venereal disease research laboratory) test
Treponemal tests:
- EIA – very sensitive and specific (if positive, likely to have syphilis)
- TPHA / TPPA (treponema pallidum haemagglutinin assay) - confirmatory test if EIA positive
- FTA-ABS (fluorescent treponemal antibody absorption)
- Neurosyphilis -> CT/MRI head, LP (raised WCC, raised protein), TPPA >1: 320
Management
(mother; any adult):
Early (1st and 2nd, early latent) -> Benzathine-Pen (IM, STAT) OR doxycycline (BD, 14/7)
Late (late latent, non-neuro 3rd) -> Benzathine-Pen (IM, OW, 3/52) OR doxycycline (BD, 28/7)
Neurosyphilis -> Penicillin (IV, 4-hourly, 14/7) OR doxycycline (BD, 28/7)
- Prednisolone (OD, 3/7) started 24 hours before treatment to avoid Jarish-Herxheimer reaction
- Jarish-Herxheimer reaction = release of proinflammatory cytokines in response to dying organisms
- S/S: 24 hours of a febrile myalgia – rare/serious consequences – admit mothers >22w when treating
Follow-up à partner notification, repeat bloods at 3/12 (4-fold drop in RPR)
Complications
Risks in Pregnancy -> benzathine penicillin greatly improves foetus outcomes
- FGR
- Foetal hydrops
- Congenital syphilis (may cause long-term disability)
- Stillbirth
- Preterm birth
- Neonatal death
Congenital syphilis -> (see obstetrics) rash on soles of feet and hands ± bone lesions
