STI's - an introduction Flashcards
What is a commensal micro-organism
A micro-organism that derives food or other benefits from another organism without hurting or helping it.
Pathogen
What is a Pathogen
micro-organism that can cause disease
different types of infection
No symptoms sub-clinical
Symptoms clinical
give examples of sexually transmissible organisms - how do they spread
A virus, bacteria, protozoan, insect or arthropod which can be spread by sexual contact
- Commensal
- pathogen
Sexually transmitted infection (STI) - is caused by?
give 2 examples
pathogen spreading through sex
- Neisseria gonorrhoeae
- HPV type 6
Sexually transmitted disease (STD) - what is this?
Give 2 examples
A disorder of structure or function caused by a sexually transmitted pathogen
- Pelvic inflammatory disease
- Genital warts
Venereal Diseases (3)
- Syphilis (Treponema pallidum pallidum)
- Gonorrhoea (Neisseria gonorhoeae)
- Chancroid (Haemophilus ducreyi)
Bacteria infections (3) - organisms
Chlamydia trachomatis
Klebsiella granulomatis
Mycoplasma genitalium
Virus infections (4)
HSV
HIV
HPV
Molluscum contagiosum virus
parasite organisms (3)
Pthirus pubis
Sarcoptes scabei
Trichomonas vaginalis
most common infections that are controversial?
- Mycoplasma hominis
- Ureaplasma urealyticum
- Bacterial vaginosis
- Genital candidosis
Features STI’s share? (4)
- They are all infectious/contagious
- Asymptomatic most of the time
- Unpredictable minority suffer significant complications
- Totally avoidable
implications/management of STI’s? (4)
Sexual contact tracing
Can’t eradicate just by treating the symptomatic
Early detection and treatment needed
Primary prevention is the goal
Most likely to cause STI’s - list of sexual contact (8)
Group sex Anal sex Vaginal sex Oral sex - cunnilingus Oral sex - fellatio Touching someone else’s genitals with your genitals. Mutual masturbation ‘Pants on’ cuddling
Skin contact only conditions (4)
pubic lice (Pthirus pubis) Scabies (Sarcoptes scabeii) Warts (human papilloma virus types 6 &11) Herpes (Herpes Simplex Virus types 1 & 2)
Common group sex condition
hep c
Why are STIs important? (3)
STDs cause morbidity and can even kill.
Unpleasant symptoms – grouped in to syndromes
Psychological distress
Ulceration often seen in (2)
secondary syphillis
herpes sv
lumps often seen in?
genital wards
malloscum contagiosum
genital discharge
Gonorrhoea
chlamydia
Non-genital discharge
- chlamydia in the eyes
- Gonorrhoea in the eyes
rashes can occur with (
scabies
syphillis
HIV
crab lice
Systemic symptoms (5)
Fever Rash Lymphadenopathy Malaise Arthralgia and arthritis
Late complications of chlamydia?
Infertility
late complications of sti’s?
Cancer. 250,000+ deaths globally from cervical cancer - HPV
300,000 adverse pregnancy outcomes from syphilis per year.
R0=cD - applies to?
every disease - the reproductive number
if R> 1, epidemic is sustained
Rate of acquiring new partners? (5)
increased numbers of partners/person increased concurrent partners more people having anal sex more men reporting sex with men (also increased condom usage).
cores meaning
likely to have sex with someone like them
- leads to high prevalence within a subpopulation (core) but limited spread through the wider community.
chains and random mixing?
Some ‘cores’ are very big – eg heterosexual men and women.
Random mixing leads to lower prevalence but wider dissemination along ‘chains’.
Most people have few sexual contacts over a given period of time and so chains are quite short
Principles of a consultation in someone with a possible STI? the 4 elements
a good history
partner notification
HIV testing
health promotion
important things to ask in consultation?
Presenting complaint
History of presenting complaint
PM/SHx
DHx
Include a gynae history.
Need to ask direct questions about symptoms
Eg “discharge from the penis/pain in abdomen?”
The sexual history
- Determining possible cause of symptoms
- Detecting high-risk behaviour and advising on risk reduction.
- Tracing contacts
sexual history questions? (9)
- When did you last have sexual contact?
- Casual contact vs ‘regular’ partner?
- How long were you going out with them for?
- Were they male or female?
- Asking about nature of sex act sometimes useful
anxiety about a specific incident - If it’s going to alter where you swab from eg MSM
- Did you use condoms?
- Other contraception used
- Nationality of contact
Assessment of longer-term sexual risks (men) (7)
Have you ever had sexual contact with another man? Have you ever injected drugs? Sexual contact with anyone who’s injected drugs? someone from outside the UK? (clarify) Medical treatment outside UK? (clarify) Paid for sex or been paid?
Partner notification (‘contact tracing’) - what are the 2 ways of doing this?
Patient tells contacts “client referral”
NHS tells contact “provider referral”
Offer/recommend further testing -why/when may you do this?
- Most STIs are risk factors for HIV acquisition and transmission.
- If someone has one STI (eg chlamydia) they could have another (eg HIV)
Health promotion for STI’s? (5)
- Condoms prevent transmission of some STIs - Eg HIV, chlamydia, gonorrhoea - Not so good at preventing transmission of other STIs; eg herpes and warts - Oral sex carries risks too Not as great as vaginal or anal sex fellatio more than cunnilingus Address hazardous drug use. Vaccination HIV pre-exposure prophylaxis
