Syphilis

Question 1

Syphilis - background

Answer 1

1. Caused by the spirochaete Treponema pallidum, a corkscrew-shaped bacterium
2. Current rate 8.9 per 100,000, low incidence in Australia
3. Most commonly spread through sexual contact. Can also be transmitted through blood transfusion or inoculation (needlestick/scalpel) with material from infected lesions
4. Routine antenatal screening
5. Rates higher in indigenous community and those born overseas

Question 2

Syphilis - classification

Answer 2

Early syphilis = 2y or unknown duration

4. Late latent syphilis (asymptomatic)
5. Tertiary syphilis (cardiovascular, CNS or skin/bone involvement)

Question 3

Syphilis - symptoms

Answer 3

Primary syphilis (3)

1. 10-90d post-infection
2. Painless, genital ulcer with indurated edges (chancre) - may pass unnoticed on cervix
3. Inguinal lymphadenopathy

Secondary syphilis (5)

1. Occurs within first 2y of infection
2. Generalised polymorphic rash affecting palms and soles
3. Generalised lymphadenopathy
4. Genital condyloma lata (clusters of soft, moist lumps in skin folds of anogenital area)
5. Mucosal lesions, hepatitis, meningitis, anterior uveitis

Tertiary syphilis (3)

1. Neurosyphilis = tabes dorsalis (slow degeneration of nerves in dorsal column), dementia
2. Cardiovascular syphilis = commonly affecting the aortic root
3. Gummata = inflammatory plaques or nodules

Question 4

Syphilis - dx

Answer 4

1. Serology for IgG (Treponema-specific enzyme immune assays, such as Treponemal IgG EIA)
2. Primary lesion smear may show spirochaetes on dark field microscopy
3. Other serological tests required to correctly stage and tx the infection (bc all treponemal-specific tests remain positive after successful tx, rendering them useless as a test-of-cure). Rapid plasmin reagin test (RPR) = most commonly used test in Australia

Question 5

Syphilis - mx

Answer 5

1. Early syphilis = benzathine penicillin 1.8g IM, single dose or procaine penicillin 1.5g IM, daily for 10d
2. Late latent syphilis = benzathine penicillin 1.8g IM, once weekly for 3 wks, or procaine penicillin 1.5g IM, daily for 15d
3. Tertiary syphilis = benzylpenicillin 1.8g IV, 4-hourly for 15d