STI infections & common genital symptoms Flashcards
What is a commensal micro-organism?
A micro-organism that derives food or other benefits from another organism without hurting or helping it
What is a pathogen?
A micro-organism that can cause disease
What is a sexually transmissible microbe?
A virus, bacteria or protozoan which can be spread by sexual contact
What is an STI?
An infection by a pathogen which is sexually transmissible and which is unlikely to be transmitted by non-sexual means
What is an STD?
A disorder of structure or function caused by a sexually transmitted pathogen
What are examples of bacterial STI’s?
Chlamydia trachomatis
Klebsiella granulomatis
Mycoplasma genitalium
What are examples of viruses which are STI’s?
HSV
HIV
HPV
Molluscum contagiosum virus
What are examples of parasites which cause STI’s?
Pthirus pubis
Sarcoptes scabei
Trichomonas vaginalis
What are the characteristics on an STI?
Transmissible
Asymptomatic most of time
All manageable, but not always curable
Avoidable
What are implications of STI’s?
Partner notification
Hard to eradicate, prevention
Treatment & prevention of complications
Primary prevention - education
What can be spread via genital contact only?
Pubic lice
Scabies
Warts (HPV 6 &11)
Herpes (HSV 1 & 2)
What can be spread via group sex?
Hepatitis C
Why are STIs important?
Morbidity Unpleasant symptoms Psychological distress Cost of resources Common
What are common STI presentations?
Ulceration
Lumps
Discharge
Rashes
What are systemic symptoms of STIs and adverse outcomes?
Fever Rash Lymphadenopathy Malaise Infertility Cancer Adverse pregnancy outcomes
Why do diagnoses of STIs change over time?
True change in number of cases
Change in diagnoses but no actual change in number of cases
What does the equation R0=βcD mean?
R0 = reproductive number (average no of infections produced) β = likelihood of transmission c = rate of acquiring new partners D = duration of infectivity
With the equation R0=βcD, what does R0>1 mean for no of STI cases?
Epidemic is sustained
With the equation R0=βcD, what does R0<1 mean for no of STI cases?
Epidemic reduces
What is the NATSAL study?
National survey of sexual attitudes and lifestyle every 10yrs
What is the sexual network analysis?
Modelling and mapping spread of STIs
What are ‘cores’ and assortative mixing?
High prevalence within subpopulation but limited spread through wider community e.g. IVDU
What does random mixing mean for STI spread?
Lower prevalence but wider dissemination along ‘chains’
What are the principles of management in someone presenting with STI?
History
HIV testing
Partner notification
Health promotion
What is necessary in sexual history?
Presenting complaint - direct q's about symptoms HxPC PM/SHx DHx Gynae Hx
What are questions to ask in sexual history?
When did you last have sexual contact? Casual contact vs regular partner? How long with partner? Male or female partners? Nature of sex act sometimes Did you use condoms? Other contraception used? Nationality of contact?
What are risk assessment questions for a man?
Have you ever had sexual contact with a man?
Have you ever injected drugs?
Sexual contact with someone who has injected drugs/outside the UK?
Medical treatment outside UK?
Involvement with sex industry/prostitute?
What are the two ways of partner notification ‘contact tracing’?
Patient tell contacts - ‘client referral’
NHS tells contacts - ‘provider referral’
If someone has an STI what should you offer?
HIV testing
What are health promotion options for STIs?
Condoms - HIV, chlamydia, gonorrhoea NOT herpes, warts
Alcohol and drug advice
What are common genital symptoms/presenting complaints?
Discharge Pain Rashes Lumps and swellings Cuts, sores, ulcers Itching Change in appearance Vague sense something not right
What could be causing STI-like symptoms?
STI
Other microbial problem
Non-microbial
What are microbial conditions not regarded at STDs?
Vulvovaginal candidosis Bacterial vaginosis Balanoposthitis Tinea cruris Erythrasma Infected sebaceous glands Impetigo Cellultitis
What organism usually causes vulvovaginal candidosis?
Candida albicans
Where is candida albicans in vulvovaginal candidosis usually acquired from?
Bowel
What are the signs/symptoms of vulvovaginal candidosis?
Asymptomatic
Symptomatic ‘thrush’: itch, discharge ‘cottage cheese’ or just increased amount
What are the risk factors for vulvovaginal candidosis?
Diabetes Oral steroids Immune suppression Pregnancy Reproductive age group
How is vulvovaginal candidosis diagnosed?
History
Exam findings: fissuring, erythema with satellite lesions, discharge
What are the investigations for vulvovaginal candidosis?
Gram stained preparation
Culture
What is the treatment for vulvovaginal candidosis?
Azole antifungals: clotrimazole PV once + clotrimazole HC if vulvitis
or
fluconazole PO once
Maintain skin - avoid irritants, treat dermatitis
What is the commonest cause of abnormal vaginal discharge?
Bacterial vaginosis
What are the signs/symptoms of bacterial vaginosis?
Asymptomatic 50%
Watery grey/yellow ‘fishy’ discharge
Worse after period/sex
Sore/itch from dampness
What is bacterial vaginosis caused by?
Imbalance of bacteria rather than infection
Biofilm problem
What are the bacteria changes in bacterial vaginosis?
Increased anaerobes
Reduced lactobacilli
What are complications associated with bacterial vaginosis?
Endometriosis
Premature labour
Risk of HIV acquisition
What is the investigation for bacterial vaginosis?
Gram stained smear of vaginal discharge
What is the treatment for bacterial vaginosis?
Metronidazole: oral or vaginal gel
Clindamycin: vaginal
What is Zoon’s balanitis?
Chronic inflammation secondary to overgrowth of commensal organism plus foreskin malfunction
What is candidal balanitis?
Inflammation to the glans of the penis due to candida albicans
What usually causes impetigo on the penis?
Staph aureus
Strep pyogenes
What is a genital dermatophyte infection usually caused by?
Trichophyton rubrum
What is tine cruris?
Fungal infection that affects the skin of your genitals, inner thighs and buttocks
What is erythrasma?
A superficial skin infection that causes brown, scaly skin patches
What are Fox-Fordyce spots?
Visible sebaceous glands that are present in most individuals. They appear on the genitals as small, painless, raised, pale, red or white spots or bumps 1 to 3 mm in diameter that may appear on the scrotum, shaft of the penis or on the labia, as well as the inner surface (retromolar mucosa) and vermilion border of the lips of the face
What are vulval papillomatosis?
Pink, asymptomatic fine projections of the vestibular epithelium or labia minora
What are penile pearly papules?
Small protuberances that may form on the ridge of the glands of the penis, normal anatomical variation
What are Tyson’s glands?
Modified sebaceous glands located around the corona and inner surface of the prepuce of the human penis
What are other causes of genital symptoms?
Pain syndromes Dermatoses Congenital Trauma Neoplasm Manifestations of systemic disease
