Infections of the Genital Tract Flashcards
What is the difference between a sexually transmitted infection and a sexually transmitted disease?
STI
- Includes both symptomatic and asymptomatic cases
STD
- Symptomatic cases only
Which groups are most at risk of STIs?
Young people Certain ethnic groups Low socio-economic status groups Specific aspects of sexual behaviour - Age at first sexual intercourse - Number of partners - Sexual orientation - Unsafe sexual activity
Why is there an increase in incidence of STIs?
Increased transmission
- Changing sexual and social behaviour
- Increasing density and mobility of populations
Increased GUM attendance
Greater public, medical and national awareness (e.g. campaigns)
Improved diagnostic methods including screening programs
What are some of the burdens of STIs?
Both acute and chronic/relapsing infections
Stigma - impact on diagnosis and tracing contacts
Consequent pathology
- Pelvic inflammatory disease & infertility
- Reproductive tract cancers
Disseminated infections
Transmission to foetus/neonate
What is the general diagnosis of STIs?
Patient presents with genital lesions/problems to GP or GUM clinic
- Ulcers, vesicles, warts, etc…
- Urethral discharge or pain
- Vaginal discharge
Clinician notes non-genital clinical features suggestive of STI
- Disseminated disease
Detection of asymptomatic cases - contact tracing/screening)
What is the general management of STIs?
Treatment preferably single dose/ short course
Co-infections are common - screen and consider empiric treatment for other STIs
Contract tracing - patient and public health management
Sexual health education, advice on contraception, and detailed instruction on the practice and need for safer sex
Describe the Human Papillomaviruses in terms of STIs
> over 100 types of this DNA virus
Most common viral STI (~4% young adults in their life)
Cutaneous, mucosal and anogenital warts
- mainly HPV 6 & 11
- Benign, painless, verrucous epithelial or mucosal
outgrowths on penis, vulva, vagina, urethra, cervix,
perianal skin
High-risk types (oncogenic) - HPV16 & HPV18
- Associated with cervical (>70%) and anogenital cancer
- 2500 cases cervical cancer in 2012 - most common
cancer in women 15-34
How do you diagnose Human Papillomaviruses?
Clinical, biopsy & genome analysis, hybrid capture
How do you treat someone with Human Papilloma virus?
No treatment - spontaneous resolution (70% 1 yr, 90% 2 yrs)
Topical podophyllin, cryotherapy, intralesional interferon, imiquimod, surgery
What screening is available for HPV?
Cervical Pap smear cytology (Use a different staining technique now)
Colposcopy + acetowhite test
Cervical swab - HPV hybrid capture (40% of 20-24 yr olds positive)
Are there vaccines available for HPV?
Yes
Two types
- Cervarix (HPV 16 & 18) initially used in UK
- Gardasil (HPV 6,11,16 & 18) from 2011
Vaccine offered to girls 12 - 13 (2 doses)
99% effective in preventing HPV 16 & 18 - related cervical abnormalities in those not already infected
Describe chlamydia in terms of STIs
Caused by chlamydia trachomatis
Obligate intra-cellular bacterium
Non-specific genital chlamydial infections
- Serotypes D -K
Males - urethritis, epididymitis, prostatitis, proctitis (anus)
Females - often asymptomatic, urethritis, cervicitis, salpingitis (fallopian tubes) perihepatitis (the covering of the liver, also known as fitz-hugh-curtiz syndrome.
Ocular inoculation - conjunctivitis
Neonatal infection - inclusion conjunctivitis, pneumonia
How do you diagnose chlamydia?
Endocervical and urethral swabs - NAAT
1st void urine - NAAT
Neonatal infection - conjuctival swab (NAAT)
What is the treatment for chlamydia?
Doxycycline or azithromycin
Erythromycin in children
Is there screening for chlamydia?
Yes
50% of all cases from chlamydia screening programme
- Targets sexually-active under 25s
- Urine (M&F) or swab (F)
- Nucleic acid amplification test (NAAT)
- Dual testing (with N. gonorrhoeae) available
Describe the herpes simplex virus in terms of STIs
Primary genital herpes - extensive painful genital ulceration, dysuria, inguinal lymphadenopathy, fever
Genital herpes is usually associated with HSV2 (HSV 1 causes cold sores)
Recurrent genital herpes - asymptomatic to moderate (latent infection in dorsal root ganglia)
How do you diagnose the herpes simplex virus?
PCR of vesicle fluid and/or ulcer base
What is the treatment for herpes simplex virus?
Aciclovir (1° & severe disease)
Aciclovir prophylaxis for frequent recurrences
Barrier contraception - reduced risk of transmission
Describe gonorrhoeae in terms of STIs
Caused by Neisseria gonorrhoeae
Gram negative intracellular diplococcus
Males - urethritis, epididymitis, prostatitis, proctitis, pharyngitis
Females - asymptomatic, endocervicitis, urethritis, PID which may lead to infertility
Disseminated gonococcal infection
- Bacteraemia, skin & joint lesions
How do you diagnose gonorrhoeae?
Swab from urethra, cervix (throat, rectum) or urine (NAAT)
- Gram stain (pus or normally sterile site)
- Fastidious organism requiring special media ( need to
let lab now what you are looking for)
What is the treatment for gonorrhoeae?
Ceftriaxone (IM), increasing resistance to many other agents
All patients treated (& tested) for chlamydia with azithromycin which also may prevent emergence of resistance to cephalosporins
Describe syphilis in terms of STIs
Treponema pallidum
Spirochaete
Aetiological agent of syphilis - great mimicker of symptoms of many other diseases
Most cases men and MSM (men who have sex with men)
Multi-stage disease
- 1° - indurated, painless ulcer (chancre)
- 2° - 6 to 8 weeks later - fever, rash,
lymphadenopathy, mucosal lesions
- 3° - neurosyphilis (GPI tabes dorsalis), cardiovascular syphilis, gums (local destruction)
Congenital syphilis
How do you diagnose syphilis?
Treponema pallidum cannot be grown
Dark-field microscopy needed
Serology
Initial screening with EIA antibody test then +ves
- Rapid Plasma Reagin RPR titre (cross-reacting antigen)
- TP particle agglutination TPPA
- Serologic pattern interpreted (false positives,
response to treatment, etc)
What is the treatment for Treponema pallidum?
Penicillin & ‘test of cure’ follow up
Name some less common STIs
They are mainly tropical
Inguinal lymphadenopathy may be cause by these:
LGV (lymphogranuloma venereum)
- C. trachoma serotypes L1, L2 & L3
- Rapidly healing papule (small defined bump) then
inguinal bubo (swelling of lymph nodes)
- Recent clusters in Europe in MSM
Chancroid (Haemophilus ducreyi)
- Painful genital ulcers
- Looks like syphilitic lesion but painful
Granuloma inguinale/Donovanosis (Klebsiella granulomatis)
- Genital nodules -> ulcers
What are three most common causes of abnormal vaginal discharge?
Trichomonas vaginalis
Vulvovaginal candidiasis
Bacterial vaginosis
Describe trichomonas vaginalis in terms of STIs
Predominantly sexually transmitted
Flagellated protozoan
Trichomonas vaginitis
- Thin, frothy, offensive discharge
- Irritation, dysuria, vaginal inflammation
How do you diagnose trichomonas vaginitis?
Vaginal wet preparation +/- culture enhancement
What is the treatment for trichomonas vaginalis?
Metronidazole
Describe vulvovaginal candidiasis in terms of STIs
Often called vaginal thrush
Not often uniquely sexually transmitted but can be
Caused by candida albicans & other candida species
- May be part of normal GI & genital tract flora
Risk factors
- Antibiotics, oral contraceptives, pregnancy, obesity,
steroids, diabetes
Profuse, white, itchy curd-like discharge
How do you diagnose vulvovaginal candidiasis?
High vaginal smear (+/- culture)
They stain gram positive
What is the treatment for vulvovaginal candidiasis?
Topical azoles or nystatin
Or oral fluconazole
Describe bacterial vaginosis (BV) in terms of STIs
Perturbed normal flora
- Gardnerella (probably not cause, just occurs with
change of flora), anaerobes, mycoplasmas
Scanty but often fishy discharge
How do you diagnose bacterial vaginosis?
Vaginal pH >5, KOH whiff test
Laboratory diagnosis - HVS (High vaginal specimen)
gram stained smear
- ‘Clue’ cells - epithelial cells studded with gram
variable coccobacilli
- Reduced numbers of lactobacilli
- Absence of pus cells
What is the treatment for bacterial vaginosis?
Metronidazole
Describe briefly scabies and pubic lice in terms of STIs
Not exclusively sexually transmitted
Scabies can affect the genetalia and spread sexually
Pubic lice (pediculosis pubis)
- Distinct from the other human (body) lice
- The ‘crab louse’ (Phthirus pubis)
What are some general important points in relation to genital tract infections?
Asymptomatic & symptomatic disease - common
Marked differences in worldwide epidemiology
Sexual and travel history important
Prompt diagnosis & early treatment
ADVICE, COUNSELLING AND EDUCATION
- role of GUM in contact tracing & other ppunlic health
measures
