11 - STIs Flashcards
What are some risk factors of contracting an STI?
- Age 15-24
- Lower age of first intercourse
- Increased number of sexual partners
- Black ethnicity
- Low socio-economic status
- Sexual orientation
- Lack of barrier contraception
- Lack of immunisation
What are some infections that can be spread through sexual contact but also in other ways?
HIV
Hep B/C
How are most STIs diagnosed?
Over 50% are asymptomatic so mainly picked up on screening tests
What bacteria causes chlamydia and what are the symptoms in men and women?
- Chlamydia Trachomatis
- Obligate intracellular bacterium not seen on gram staining as no cell wall. Stops phagolysosome fusion
Men: urethritis, dysuria, epididymitis, prostatitis, discharge
Women: typically asymptomatic but possible discharge, dyspareunia or post coital/intermenstrual bleeding
What is the most common STI in the UK?
Chalmydia
(however gonorrhoea is most common cause of discharge)
How can we test for and treat chlamydia?
- NAAT via vaginal swab or first stream male urine
- Doxycycline or Azithromycin
- In pregnancy or allergy it is erythromycin
What other complications can chalmydia trachomatis cause?
- PID
- Conjuctivitis (especially giving birth)
- Reactive arthritis
What bacteria causes gonorrhoeae and what are the symptoms in men and women?
- Neisseria Gonnorhoeae
- Gram negative intracellular diplococci
- 90% of men are symptomatic and can infect any area with mucosal surface
Men: thick yellow discharge and dysuria
Women: typically asymptomatic but can cause discharge and lower abdominal pain
What complications can neisseria gonorrhoeae lead to?
- Epididymo-orchitis in men
- PID in women
- Disseminated infections
How can we treat gonorrhoeae?
Ceftriaxone and azithromycin to boost effectiveness of first antibiotic, reduce risk of resistance and to treat chlamydia as common co-infection
What is non-gonococcal urethritis (NGU)?
Inflammation of the urethra with associated discharge with the causative organism being anything but N.Gonorrhoeae. Doesn’t have to be sexually transmitted
- Chlamydia Trachomatis
- Mycoplasma genitalium
- Trichomonas vaginalis
- Pathogen negative
How do we investigate common STIs in men?
- Mid stream urine for cultures and sensitivities
- Urethral swab if asymptomatic with pharyngeal and anal swabs
- Blood tests for syphilis and HIV, Hep B/C
What can be some causes of vaginal discharge?
If physiological discharge will be clear
What bacteria causes syphilis and what are the different stages of this disease?
- Treponema Pallidum
- Spirochete spread through direct contact or vertical transmission
- Most common in men 25-33 and many will be co-infected with HIV
How can we test for and treat syphilis?
- Swabs and blood tests
- Microscopy, PCR, serology
- Treatment depends on stage but penicillin based antibiotics
What organisms causes trichomoniasis and what are the symptoms of this?
- Trichomonas Vaginalis
- Protozoa with flagella that grows best at pH 6
- Lots of yellow odorous discharge
Men: often asymptomatic but can have dysuria and discharge
Women: yellow vaginal discharge and irritation of the vulva
How can we test for and treat trichromoniasis?
- Needs to be treated as can be passed to men and cause NGU
- Swabs
- Metronidazole
What is the normal range of pH in the vagina?
3.5 - 4.5
What are two non sexually transmitted diseases that affect the female reproductive tract?
- Candidiasis (Candida albicans)
- Bacterial vaginosis (Gardnerella vaginalis)
What is candidiasis caused by, what are the symptoms and how is it treated?
- Candida Albicans
- Yeast
- Activated in immunocompromised states e.g diabetes
- Favours high oestrogen e.g OC pill
- White discharge
- Very itchy and maybe dyspareunia
- High vaginal swab and treated with oral/topical azoles
What is bacterial vaginosis caused by, what are the symptoms and how is it treated?
- Gardnerella Vaginalis
- Anaerobe
- Excessive washing can alter flora
- Offensive fishy discharge WITHOUT pruitis or pain
- High vaginal swab and treated with metronidazole
How would you investigate common STIs in women?
- Chlamydia is vulvo-vaginal if asymptomatic and endocervical otherwise
- Ulcer swabs and rectal/pharyngeal swabs for serology
If you suspect an STI in a woman what questions should you ask whilst taking her history?
What is the most common viral STI, how is it detected and treated?
- HPV leading to painless genital/cutaneous warts
- DNA non-enveloped
- Strains 6&11 associated with genital warts and 16&18 associated with cervical cancer
- PCR on biopsy/swab
- Gardasil vaccination for all 4 strains or Cervarix for 16/18
- Usually regress on own or with topical treatments
