STI: Infections of the Genital Tract Flashcards
Commensal micro-organism
A micro-organism that derives food or other benefits from another organism without hurting or helping it.
Pathogen
A micro-organism that can cause disease
Infection
The invasion of all or part of the body by a micro-organism
What is the difference between a clinical and sub-clinical infection?
- Clinical= symptoms
- Subclinical= no symptoms
Sexually transmissible microbe
- A virus, bacteria or protozoan which can be spread by sexual contact
- Can be commensal or pathogen
Sexually transmitted infection
An infection by a pathogen which is sexually transmissible and which is unlikely to be transmitted by non-sexual means
Sexually transmitted disease
A disorder of structure or function caused by a sexually transmitted pathogen
Give examples of venereal diseases and their causative agent.
- Syphilis (Treponema pallidum pallidum)
- Gonorrhoea (Neisseria gonorhoeae)
- Chancroid (Haemophilus ducreyi)
Give examples of sexually transmitted bacteria in the UK.
- Chlamydia trachomatis
- Klebsiella granulomatis
- Mycoplasma genitalium
Give examples of sexually transmitted viruses in the UK.
- HSV
- HIV
- HPV
- Molluscum contagiosum virus
Give examples of sexually transmitted parasites in the UK.
- Pthirus pubis
- Sarcoptes scabei
- Trichomonas vaginalis
Give examples of infection vs colonisations.
- Mycoplasma hominis
- Ureaplasma urealyticum
- Bacterial vaginosis
- Genital candidosis
What are the features of an STI?
- Transmissible (partner notification
- Asymptomatic (hard to eradicate, requires prevention)
- All manageable but not curable (treatment and prevention complications)
- Avoidable (primary prevention education)
Give examples of sexual contact.
Greatest risk of infection -Group sex -Anal sex -Vaginal sex -Oral sex -Touching someone else's genitals with yours -Mutual masturbation Least risk of infection
What conditions can be transmitted through genital contact alone?
- Pubic lice (Pthirus pubis)
- Scabies (Sarcoptes scabeii)
- Warts (human papilloma virus types 6 &11)
- Herpes (Herpes Simplex Virus types 1 & 2)
What condition is often transmitted through group sex?
Hepatitis C
Why are STIs important?
- Cause morbidity and mortality
- Drain on resources
- They’re common
What systemic symptoms can STIs present with?
- Fever
- Rash
- Lymphadenopathy
- Malaise
- Infertility
What are the possible complications of STIs?
- Cancer
- Adverse pregnancy outcomes
How can we tell if there is change in the number of cases of STIs?
- Average number of infections produced(Ro) is equal to the (likelihood of transmission) (rate of acquiring new partners) (duration of infectivity)
- If Ro >1 then epidemic is sustained, if <1 then epidemic reduced
What 3 things should parents know about preventing cervical cancer?
- HPV vaccination is the best way to prevent many types of cancer
- HPV vaccination is recommended at ages 11-12
- HPV vaccination is reducing HPV disease
How are people’s attitudes to sex changing?
- Increased numbers of partners/person
- Increased concurrent partners
- More people having anal sex
- More men reporting sex with men
- (Also increased condom usage).
Why is more STI testing occurring?
- Greater awareness
- More people asking for tests
- More clinicians considering STIs
What testing methods are used?
- Nucleic acid amplification testing
- Enzyme immunoassays for chlamydia
Why do certain STIs spread through certain populations?
Some people have sex with people like them (similar lifestyle)
-Leads to high prevalence within a subpopulation (core) but limited spread through the wider community
How do STIs disseminate amongst populations?
- 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
What are the principles of management for someone presenting with symptoms suggestive of STI?
- A good history
- Partner notification
- HIV testing
- Health promotion
What are the components of an STI history?
- Presenting complaint
- HoPC
- PM/SHx
- DHx
- Include gynae history
- Ask directed questions about symptoms
What is the sexual history necessary for?
- Determining possible cause of symptoms
- Detecting high-risk behaviour and advising regarding educing future risk
- Tracing contacts
What questions should be asked in the sexual history?
- When did you last have sexual contact?
- Casual contact vs ‘regular’ partner?
- Were they male or female?
- Asking about nature of sex act sometimes useful
- Did you use condoms?
- Other contraception used
- Nationality of contact
What questions are asked when risk assessing a male?
- Have you ever had sexual contact with a man?
- Have you ever injected drugs?
- Sexual contact with anyone who’s injected drugs or someone from outside the UK? (clarify)
- Medical treatment outside UK? (clarify)
- Involvement with sex industry. (had sex with prostitute)
What are the 2 methods of partner notification?
- Patient tells contacts “client referral”
- NHS tells contact “provider referral”
Why is further STI testing often offered to those when they are diagnosed?
- Most STIs are risk factors for HIV acquisition and transmission.
- If someone has one STI (eg chlamydia) they could have another (eg HIV)
What health promotion should be offered?
- Condom usage for prevention of transmission of HIV, chlamydia, gonorrhoea
- Condoms not good at preventing herpes and warts
- Oral sex carried risks too (fellation more than cunnilingus)
- Alcohol and drug usage
