Week 6.0 - Genital Infections Flashcards
What is a STD?
-Symptomatic cases only
Papillomaviruses cause…
…genital warts (genital cancers)
Chlamydia trachimatis causes…
…chlamydia, urethritis and lymphogranuloma venerem
Herpes simplex causes…
…genital herpes
Neisseriae gonorrhoeae causes..
…gonorrhea
Treponema pallidum causes…
…syphilis
Name some specific at risk groups of STI
- Young people
- Certain ethnic groups
- Low socio-economic status groups
- Certain aspects of sexual behavior
What are the possible reasons for increased incidence of STIs?
- Increased transmission (changing sexual/social behaviour and increasing population density)
- Increased GUM attendence
- Improved diagnostic methods
What is an STI?
-Symptomatic and asymptomatic infections transmitted by sexual activity
Give 3 complications of STIs
- Pelvic inflammatory disease
- Infertility
- Reproductive tract cancers
- Disseminated infections
- Transmission to fetus/neonate
Under what circumstances are STIs generally diagnosed?
- Patient presents with genital problems/lesions
- Clinician notes non-genital clinical features suggestive of STI
- Screening/contact tracing of asymptomatic infections
Discuss the general management of STIs
- Short course/single dose of antibiotics
- Screening for co-infections (empiric treatment?)
- Contact tracing
- Sexual health education/advice on contraception
What is the most common viral STI?
-Human papillomavirus
What type of virus is humanpapilloma virus?
-DNA virus
Which serotypes of HPV are the most common in causing genital warts?
-6 and 11
How does HPV present?
-Benign painless verrucous epithelia or mucosal outgrowths on the penis, vulva, vagina, urethra, cervix or perianal skin
Which serotypes of HPV are high risk for cervical or anogenital cancer?
-16 and 18
How is HPV a carcinogen?
- Expresses E6 and E7 proteins that inhibit p53 and pRB respectively, both of which are involved in cellular proliferation
- p53 is a TSG which suspends the cell cycle to trigger DNA repair mechanisms or mediates apoptosis in response to DNA damage
- pRB is an oncogene that prevents movement past the restriction point until the cell is ready for proliferation
How is HPV diagnosed?
-Clinical diagnosis or biopsy and genome analysis
What is the treatment for HPV?
- None-spontaneous resolution (1-2 years)
- Topical podophyllin, cryotherapy
Does HPV currently have a screening programme?
-It is screened for if indicatied in cervical smears
What serotypes does the HPV vaccine gardasil protect against and who gets it?
- 6,11,16 and 18
- Girls aged 12-13
What type of bacterium is chlamydia trachomatis?
-Obligate intracellular gram-negative bacteria
What significance to diagnosis does the fact that c.trachomais is an obligate intracellular bacteria have?
-Requires special medium to culture
How can chlamydia present in males?
-Utheritis, discharge, epididymitis, prostatitis, proctitis
How can chlamydia present in females?
-Urethritis, discharge, cervicitis, salpingitis, PID, proctitis, perihepatitis (fitzhugh-curtis syndrome)
What is a commons non-genital manifestation of c.trachomatis?
-Conjunctivitis
How is chlamydia diagnosed?
- Endocervical and urethral swabs subjected to NAAT
- 1st void urine subjected to NAAT
What is NAAT?
-Nucleic acid amplification test
Outline the possible treatments of chlamydia
- Doxycycline (tetracycline) for 1-2 weeks
- Azithromycin (macrolide) for 1-3 days
- Erythromycin (in children)
Why cant you give tetracyclines to children?
-Stains teeth and bones
What is the most common presentation of chlamydia?
-Asymptomatic
What is the most common bacterial STI?
-Chlamydia
Briefly describe the screening programme for chlamydia
- Targets sexually active under 25s
- Diagnoses 50% of all cases
- At stands or sent in the post
- Urine sample or swab (F) subjected to NAAT
- Dual tests for gonorrhoea
How does herpes simplex virus present?
-Genital herpes -> extensive painful genital ulceration, dysuria, inguinal lymphadenopathy and fever
With which serotype is genital herpes associated?
-HSV2 (HSV1 usually causes coldsores)
Why is herpes a chronic condition?
- Recurrent outbreaks varying from asymptomatic to moderate as the virus remains latent in the dorsal root ganglia
- Outbreaks usually get less severe and further apart
How is herpes diagnosed?
-PCR and vesicle fluid/ulcer base
How is herpes managed?
- Acyclovir for primary outbreak and severe disease
- Can be used as a prophylaxis for frequent recurrences but unpleasant side effects
- Barrier contraception to reduce the risk of transmission
What type of bacterium is n.gonorrhoeae?
-Gram negative intracellular diplococcus
How does gonorrhoea present in males?
-Urethritis with purulent discharge, epididymitis, prostatitis, proctitis, pharyngitis
How does gonorrhoea present in women?
- Most commonly asymptommatic
- Endocervicitis, urethritis, increased vaginal discharge, bleeding between periords, PID
How does disseminated gonococcal infection present?
- Skin and joint lesions
- fever
How is gonorrhoea diagnosed?
-Urethral/cervical swab or urine subjected to NAAT
can do gram stain of pus but requires special culture medium
How is gonorrhoea treated?
-Intramuscular ceftriaxone and azithromycin for potential chlamydial infection
What type of organism is treponema pallidum?
-Spirochete
In which group of the population is syphilis most common?
-Men and MSM
Describe the disease course of syphilis?
- Multi-stage disease
1. Indurated, painless ulcer
2. 6-8 weeks later - fever, rash, lymphadenopathy, mucosal lesions
3. Latent infection - symptom free for years
4. Neurosyphilis (slow degeneration of nerves in dorsal spinal cord affecting touch and proprioception). Cardiovascular syphilis (aneurysm formation) and gummas (tumour like balls of inflammation everywhere)
How is syphilis diagnosed?
- Cannot be grown
- Dark field microscopy
- Serology -> ELISA then rapid plasma reagin titre and TP particle agglutination
How is syphilis treated?
-Intramuscular penecilli and ‘test of cure’ follow up
What is lymphogranuloma venerum?
- Infection of the lymphatics and lymphnodes
- Initial infection occurs as a self-limiting painless genital ulcer which is usually unrecognised
- Secondary infection occurs months later with buboes/abscesses in the inguinal lymph nodes
- Caused by c.trachoma serotypes L1, L2 and L3
What is chancroid?
- Bacterial infection caused by haemophilis ducreyi which presents as painful genital lesions spread by sexual contact
- Can present with painful abscesses (buboes) in the inguinal lymph nodes
What is Donovanosis (granuloma inguinale)?
- Bacterial infection caused by klebsiella granulomatis which is spread by sexual activity
- Characterised by ulcerative genital lesions which are locally destructive to the tissue.
What is trichomonas vaginalis? How does it present?
- A flagellated protozoan which causes bacterial vaginitis (trichomonas vaginitis)
- Presents as a thin, frothy offensive discharge with irritation, dysuria and vaginal inflammation
How is trichomonas diagnosed?
-Vaginal wet preperation and culture enhancement
How is trichomonas vaginitis treated?
-Metronidazole
What is vulvovaginal candidiasis? How does it present?
(thrush)
- Caused by candida albicans
- Profuse white, curd-like discharge which causes pruritis
How is thrush diagnosed?
-High vaginal smear
How is thrush treated?
- Topical azoles (clotrimazole)
- nystatin
Name 2 things which can cause pubic itching
- Scabies
- Pubic lice
What causes bacterial vaginitis? How does it present?
- Perturbed normal flora eg gardnerella
- Scanty, offensive fishy discharhe
How id BV diagnosed?
- Clinical diagnosis -> Vaginal pH>5, KOH whiff test
- Lab diagnosis -> gram stain -> clue cells with reduced lactobacilli
What are clue cells?
-Epithelial cells studded with gram variable coccobacilli
How is BV treated?
-Metronidazole
Where are LGV, chancroid and donovanosis most common?
-Tropical, developing contries
