Course:PostgradFamilyPractice/ExamPrep/99 Priority Topics/STI
Sexually Transmitted Infections - Key Features
Based on the updated PHAC (Jan 2010) Canadian Guidelines on STI
1. In a patient who is sexually active or considering sexual activity, take advantage of opportunities to advise about prevention, screening and complications of STI’s
Risk factors: Sexual contact has a known STI, under 25, more than 2 partners in the last year, serial monogamy, no contraception, IDU, other substance use, unsafe techniques (sharing toys, S&M, unprotected oral), sex work, survival sex, homelessness, anonymous partnering (internet etc), sexual assault, previous STI
Prevention: Be open to discussing low/lower risk sexual activity (mutual masturbation, oral sex, toys, etc); buying condoms in advance; limiting alcohol/drugs; harm reduction approaches (making condoms and lube available to those practicing sex work); testing prior to mutual monogamy
- Discuss that condoms quite effective for HIV, Hep B, Chlamydia and Gonorrhea, incomplete (~ 50% reduction of transmission) for HPV, HSV
- Use caution with spermicides in lube – can increase transmission of HIV/STI’s by causing disruptions and lesions in anal/vaginal mucosa
Key visits: contraception initiation or renewal, atypical symps (dysuria, vaginal infections, inguinal nodes), Pap/well woman or man exam
2. In a patient with symptoms that are atypical or non-specific for STI’s (dysuria, recurrent vaginal infections):
a) Consider STIs in the differential.
b) Investigate appropriately.
Common symptoms for women: dysuria, vaginal bleeding/discharge, vulvar or perineal lesion, pelvic pain, dyspareunia
Common symptoms for men: dysuria, urethral d/c, testicular swelling or pain, genital or perineal lesion, urethral “awareness” (very common symp of Chlamydia in males)
Other: mucocutaneous lesions/pharyngitis (gonorrhea more common), anorectal pain/discharge, anorectal abscess
Systemic simps: Fever, weight loss, lymphadenopathy, malaise, flu-like illness, generalized rash
3. In high-risk patients who are asymptomatic, screen and advise about prevention.
It’s important to highlight that we don’t routinely test for all STI’s (ie HPV, HSV)
Women (asymp): Vaginal swab (BV, trich, yeast); cervical NAAT (GC/CT), HIV, RPR
Men (asymp): Urine NAAT (GC/CT), HIV, RPR
MSM or women who have regular receptive rectal sex (asymp): Anoscope, rectal C&S
4. In high-risk patients who are symptomatic for STI’s, provide treatment before confirmation by laboratory results.
If very typical for HSV lesion, can treat with anti-viral (Acyclovir or Valacyclovir) after taking swab to decrease symptoms and risk of transmission
High-risk for bacterial STI’s with typical symptoms, treat for both Gonorrhea/Chlamydia - Cefixime 400 mg PO x1; Doxycycline 100 mg PO BID x 7 days OR Azithromycin 1g PO x1
5. In a patient requesting STI testing:
a) Identify the reasons for testing.
b) Assess patient’s risk.
c) Provide counseling appropriate to risk (i.e., human immunodeficiency virus [HIV] infection risk, non-HIV risk)
Elements of pre-test counseling for HIV: assess risk, discuss window period (95% produce antibodies within 3 months, 99% within 6 months), nominal vs. nominal testing, reportability, risks of false positive, assess supports in case of positive result, obtain consent, make a plan for obtaining results (usually 7 days).
6. In a patient with a confirmed STI, initiate:
- treatment of partner(s).
- contact tracing through a public health or community agency.
Key to complete full course of treatment and abstain from sex until 7 days after treatment of both partners for bacterial STI’s and trichomonas. No need to repeat dose if vomiting occurs >1 hour after dose is taken. Free treatment delivered to the partner from index case is available in some provinces, but generally speaking, all contacts should be seen and assessed whenever possible. Arrange follow up.
Contact tracing: has public health benefits as well as at the individual level.
Several strategies: Notification done by index case to partners, partners notified by health care professional (never naming index case), tracing and notification done by public health services (never naming index case)
Trace back period is 60 days (ie notify all sexual contacts from the past two months) for bacterial STI’s, 3 months for primary syphilis, 6 months secondary syphilis, 1 year early latent syphilis, variable for all others.
Reportable: Chlamydia, Gonorrhea, Syphilis, Acute/Chronic Hep B, HIV
7. Use appropriate techniques for collecting specimens.
Ensure universal precautions, labeling, appropriate amounts, etc etc. Self-collection looking promising, but we are not there yet.
Urethral swab: warn re discomfort, best if no void for 2 hours, introduce 3-4cm and rotate slowly
Cervical swab: remove secretions first, 1-2 cm into canal, rotate 180 deg, not in pre-pubertal girls
Pharyngeal swab: swab post. pharynx and tonsilar crypts
Anorectal swab: blindly, inserting 2-3 cm into anus, or using anoscope (better if symps), culture better than NAAT for rectal specimens
Vesicular lesion: de-roof and swab, or swab the base. Be sure to use viral culture/swab.
Chancroid lesion: If dark field microscopy available (in BC only at BCCDC), need to wash with saline and collect fluid, for DFA/IFA, can press a glass slide firmly against lesion and send to lab
8. Given a clinical scenario that is strongly suspicious for an STI and a negative test result, do not exclude the diagnosis of an STI (i.e., because of sensitivity and specificity problems or other test limitations).
NAAT most sensitive and specific for both GC/CT; sens/spec of cultures depends on quality of collection method, transport and culture medium; gram stain for GC has a sens/spec of 95% for urethral samples in males, much lower in females; NAAT of fluid for HSV approaches 100%; immunologic serologies for syphilis, HIV, Hep B generally quite good – all depend on window periods.
Canadian Guidelines on STI, updated January 2010. www.phac-aspc.gc.ca/std-mts/sti-its/pdf/sti-its-eng.pdf
Counselling guidelines for HIV testing. www.phac-aspc.gc.ca/slm-maa/terry/testing1-eng.php
Good patient resource hosted by SOGC sexualityandu website. www.sexualityandu.ca
Great info and resources for STI treatment, prevention, trends on BC Centre for Disease Control website. www.bccdc.ca
Management of STI’s via Communicable Disease Control manual. www.bccdc.ca/dis-cond/comm-manual/CDManualChap5.htm
STI decision support tools - detailed, specific management guidelines for common STI syndromes. www.crnbc.ca/Standards/CertifiedPractice/Pages/STIs.aspx