L35: Genital ulcers and lesion

Question 1

Syphilis in NZ

Answer 1

• Infectious cases uncommon in NZ, except MSM

- Late latent (non-infectious) from people born in pacific before 1960s = Yaw

Question 2

Pathology of syphilis

Answer 2

• Spirochaete infection with T. pallidum
• Evasion of immune response by:
• > enters immunologically privileged sites (eyes, brain)
• > intracellular sites
• > surface of organism immunologically inert
• Immune response to organism: vasculitis -> destruction + fibrosis

Question 3

Manifestations of syphilis

Answer 3

• Onset 9-90 days after exposure
• Anogenital ulceration (chancre)
• Rash (palms, soles)
• Ocular lesions
• Neurological signs

Question 4

Primary syphilis

Answer 4

• Onset 14-21 days after inoculation
• Initially papular then ulcerates (1-2cm, painless)
• Rubbery inguinal nodes with genital lesions
• Diagnosis by dark field microscopy or direct fluorescent antibody test before serology positive

Question 5

Secondary syphilis

Answer 5

• 4-10wks after primary lesion (may overlap)
• Haematogenous spread so may have systemic symptoms
• Rash: usually trunk (+can be soles, palms) and papular, macular or papulosquamous
• Mucus membrane lesions (large, fleshy, wart-like) usually folds in anogenital folds
• Alopecia

Question 6

Late manifestations of syphilis

Answer 6

• Late = when no longer infectious (but can reactivate immunocompromised)
• Commonly no features
• If features: aorta disease, neurological signs, gummatous change (skin, bones)

Question 7

Syphilis congenital infection

Answer 7

• Infection in fetus from 9wks but no inflammatory response until 18wks
• > 50% mid-trimester abortion or perinatal death
• Early form = changes from 1-2mths
• Late form = 80% live born undetected

Question 8

Syphilis tests

Answer 8

• Predictive value of tests poor where low prevalence
• Pregnancy significant cause of biological false positives
• Screen with EIA and if positive confirm using RPR and TPPA

Question 9

EIA, RPR, TPPA for syphilis

Answer 9

EIA:

• High sensitivity and specificity except when early
• Uses anti-human IgM and anti-human IgG

RPR:

• Non specific, non treponemal
• Usually positive 3-5wks after exposure, loses accuracy after long time
• Antibodies against lipoidal antigen and fluccolation of charcoal

TPPA:

• Specific, treponemal test, confirmatory
• Indirect agglutination assay
• Diagnosis early and late in disease
• False positives if antibodies against other treponemal organisms

Question 10

Syphilis treatment

Answer 10

• Primary, secondary or early latent = benzathine penicillin IMI stat
• Contacts treated same way
• Penicillin allergy = doxy 2x daily 7 days
• Preg: only benzathine penicillin so if allergic, desensitise
• Jarisch-Herxheimer reaction: release of breakdown products of infection -> fever, chills

Question 11

Genital herpes

Answer 11

• HSV1 = oral/labial or HSV2 = genital
• Transmission by direct contact with ulcer/vesicles
• Diagnosis: from ulcer -> HS PCR test (highly specific)
• Treat: aciclovir 3x a day for 7 days (+aciclovir for suppression 9-12months if recuurent)