Sexually Transmitted Infections Flashcards
What are the modes of transmission of STIs?
- Sexual contact with an infected person
- Direct contact of broken skin with open sores, blood, or genital discharge
- receiving contaminated blood
- mother to child during pregnancy (syphilis, HIV), childbirth (chlamydia, gonorrhoea), or breastfeeding (HIV)
What are the risk factors for STI?
- unprotected sexual intercourse
- illicit drug use
- multiple sex partners / sexual contact with people who have multiple sex partners
- prostitution
- men who have sex with men
What are the prevention methods for STI?
- abstinence and reduction in sexual partners
- use male condoms
- avoid drug use and sharing needles
- vaccinations: HepB, HPV
- pre and post exposure prophylaxis: HIV
What bacteria causes gonorrhoea?
neisseria gonorrhoeae
How is gonorrhoea diagnosed?
gram-stain and culture of genital discharge, nucleic acid amplification test (PCR)
What are the symptoms of gonorrhoea?
purulent urethral / vaginal discharge, dysuria, urinary frequency
What is the first-line treatment of gonorrhoea?
IM ceftriaxone 500mg single dose (for pt >= 150kg, use 1g)
What is the alternative treatment for gonorrhoea?
IM gentamicin 240mg + PO azithromycin 2g single dose
Is test of cure recommended for gonorrhoea?
Yes
How should sexual partners of patients with gonorrhoea be managed?
- Evaluate all sexual partners in the last 60 days / last sexual partner if > 60 days
- Abstain from sex for 7 days after treatment
- Abstain until all partners have been treated (minimise risk of reinfection)
What bacteria causes chlamydia?
chlamydia trachomatis
What is the first-line treatment regimen for chlamydia?
PO doxycycline 100mg BD x 7d
What are the alternative regimens for chlamydia?
PO azithromycin 1g single dose
PO levofloxacin 500mg OD x 7d
How should sexual partners of patients with chlamydia be managed?
- Evaluate all sexual partners in the last 60 days / last sexual partner if > 60 days
- Abstain from sex for 7 days after treatment / after completion of treatment
- Abstain until all partners have been treated (minimise risk of reinfection)
What bacteria causes syphilis?
treponema pallidium
What are the treponemal tests for syphilis?
TPHA, TPPA
How should the treponemal tests for syphilis be used?
as confirmatory tests
should not be used as monitoring as they may remain reactive even with treatment
What are the non-treponemal tests for syphilis?
RPR, VDRL
How should the non-treponemal tests for syphilis be used?
used to monitor treatment, antibody titres correlate with disease activity
What is the recommended treatment regimen for primary, secondary, and early latent syphilis?
IM Benzylpenicillin 2.4 MU single dose
What is the recommended treatment regimen for primary, secondary, and early latent syphilis, for pt with penicillin allergy?
PO doxycycline 100mg BD x 14d
What is the recommended treatment regimen for late latent (> 1yr), tertiary, and unknown duration syphilis?
IM Benzylpenicillin 2.4 MU once a week x 3 doses
What is the recommended treatment regimen for late latent (> 1yr), tertiary, and unknown duration syphilis for pt with penicillin allergy?
PO doxycycline 100mg BD x 28d
What is the recommended treatment regimen for neurosyphilis?
Crystalline penicillin 4 MU Q4H OR 18-24 MU / day, continuous infusion x 10-14d OR
IM procaine penicillin 2.4 MU OD + PO probenecid 500mg QDS x 10-14d
What is the recommended treatment regimen for neurosyphilis, for pt with penicillin allergy?
IV/IM ceftriaxone 2g OD x 10-14d
What is the monitoring for primary, secondary, and latent syphilis?
Quantitative VDRL / RPR every 3, 6, 12, 18, 24 months
success = decrease by 4-fold
What is the monitoring for neurosyphilis?
CSF exam every 6m until normal
What defines treatment failure in syphillis?
at 6 months, still have symptoms / failure to decrease antibody titer by 4-fold
What is the Jarisch-Herxheimer reaction?
fever in the first 24H of treatment
What pathogen causes genital herpes?
HSV 1 and HSV 2 (more common)
How is genital herpes transmitted?
transfer of bodily fluids / intimate skin contact
What is the clinical presentation of genital herpes?
- classical painful multiple vesicular / ulcerative lesions that develop over 7-10 days and heal in 2-4 weeks
- local itching, pain, tender, inguinal lymphadenopathy
- flu-like symptoms during the first few days after appearance of lesions
- prodromal symptoms (mild burning, itching, tingling) prior to appearance of recurrent lesions
- less severe in recurrent disease
How is genital herpes diagnosed?
- pt history, previous contact with similar lesions
- symptoms
- virologic tests: viral cell culture and PCR of HSV DNA from lesions
Are type-specific serologic tests used in the diagnosis of genital herpes in the first episode?
no, it takes 6-8w to be detectable
What are the supportive care strategies for genital herpes?
- warm saline bath
- good genital hygiene
- anti-itch
- analgesia
- counselling on natural history of the disease
What are the recommended treatment regimens for 1st episode genital herpes (non-severe)?
- PO acyclovir 400mg TDS x 7-10d
- PO valacyclovir 1g BD x 7-10d
What are the recommended treatment regimens for 1st episode genital herpes (severe)?
IV acyclovir 5-10mg/kg Q8H x 2-7d (continue with PO for a total of 10 days)
What are the recommended treatment regimens for recurrent genital herpes (chronic suppressive therapy)?
PO acyclovir 400mg BD
PO valacyclovir 500mg OD (not for those with many recurrent episodes)
PO valacyclovir 1g OD
What are the recommended treatment regimens for recurrent genital herpes (episodic therapy)?
PO acyclovir 800mg BD x 5d
PO acyclovir 800mg TDS x 2d
PO valacyclovir 500mg BD x 3d
PO valacyclovir 1g OD for 5d
