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
What symptoms can herpes simplex virus cause?
- DNA enveloped
- Lifelong infection
- Asymptomatic initially then painful ulcers/blister, discharge and dysuria.
- Can be systemic symptoms like pyrexia during an episode
Why are strains 16 and 18 of HPV so dangerous?
Usually asymptomatic and produce no genital warts but associated with cervical and anal cancer
How can we test and treat HSV?
- PCR/NAATS using swabs
- Check genitals, mouth anus
- Antivirals like aciclovir
- Cannot eradicate just limit the duration of current episode and prevent reoccurence
How can we manage an STI when we discover one?
- May be asymptomatic so consider screening for others and think about coinfections as this is common
- CONTACT TRACING
What is PID and the common organisms that cause this?
- Infection of the uterus, fallopian tubes and ovaries due to an ascending infection
- Most common: N.Gonnorhoeae and C.Trachomatis
- Gardnerella Vaginalis
- Mycopasma Genitalium
- Inserting IUDs and speculums
What can be some complications with salpingitis?
- Inflammatory exudate can fill tubes with pus leading to adhesions and obstruction and maybe tubo-ovarian abscess
- Rare cases can leave and cause peritonitis
- Ectopic pregnancy
What are some risk factors for women developing PID?
- 20-30
- Young age
- Multiple sexual partners
- Lack of barrier contraception
- Low socio-economic status
- IUCD
What are some clinicl features of PID?
- Can be asymptomatic for a long period of time then present with chronic pelvic pain or problems with fertility
- Need to ask about sexual history and contraception
- Tubo-ovarian abscess can be palpable
- Take swabs for diagnosis
What are some differentials for the symptoms associated with PID?
- May consider cancer with AUB
- Do blood tests, urinalysis and USS to rule out other differentials
- Laproscopy is gold standard for PID but only carry out if not responding to antibiotics
What are some complications with PID?
- Pelvic abscess
- Subfertility due to adhesions so increased risk of ectopic
- Peritonitis
- Fitz-Hugh Syndrome
- Chronic pelvic pain
- Retroverted uterus due to adhesions causing pain
What is Fitz-Hugh Curtis syndrome?
Inflammation of the liver capsule leading to peri-hepatitis and right upper quadrant pain.
Scarring can occur between the liver and diaphragm
How can we treat PID?
- Prevention better than cure
- Give full STI screening and contact trace
- Broad spectrum antibiotics for anaerobic organisms for over 14 days and maybe IV in severe infections
- If don’t respond to treatment do laprascopy
