Sexually Transmitted Infections Flashcards
Why is STI more appropriate than STD?
In a disease, infection leads to abnormal function
Not all sexually acquired infections cause symptoms
What is Kaposi’s sarcoma?
A rare cancer that was observed in homosexuals
This had evidence of immuno-compromise due to AIDS
How many STI diagnoses were made in 2016 and how did this compare to the previous year?
420,000
This is 3.4% less than the previous year
What are the most commonly diagnosed STIs?
- chlamydia (49%)
- genital warts (15%)
- gonorrhoea (9%)
- genital herpes (7%)
- syphyllis (1.2%)
- HIV (0.8%)
Why is there an increased frequency of STI diagnoses?
There is now more STI testing through National Screening Programme
What other reasons are there for an increasing frequency of STI diagnoses?
- routine use of more sensitive diagnostic tests
- increased awareness and self-presentation to clinics
- ongoing unsafe sexual behaviour
What is a newly used more sensitive diagnostic test?
NAATS:
nucleic acid amplification tests
Typically, which gender has an increased number of diagnoses of STIs?
Why?
Males have more diagnoses
Due to increased risk taking behaviour and increased number of sexual partners
Which age group has the greatest number of STI diagnoses?
20-24
Followed by 25-29 and then 15-19
The number of diagnoses tends to decrease with age
What was significant about people aged 15-24?
They are most likely to report at least one new sex partner of the opposite sex in one year
What % of 15-24 year olds have chlamydia, gonorrhoea, genital warts and genital herpes?
62% chlamydia
52% gonorrhea
51% genital warts
41% genital herpes
Why are older age groups vulnerable to STIs?
They are less likely to see or engage with safer sex and sexual health messaging
How has the number of diagnoses in MSM changed?
The number of diagnoses has risen sharply in the last 10 years
What is of particular concern in the MSM group?
High levels of gonorrhoea transmission
This is due to the emergence of resistance or decreased susceptibility to antimicrobials used for treatment
Which locations have a higher rate of STI diagnoses?
Urban areas, especially London
It reflects the distribution of core groups of the population who are at greatest risk
and the access to diagnosis and treatment services
Which ethnicity group has the highest rate of STI diagnoses?
Black minority ethnicity
The majority of these cases are among people living in areas of high deprivation
What is the high rate of STI diagnoses likely to be the consequence of?
- complex interplay of cultural, economic and behavioural factors
- risk behaviours between ethnic groups
What is the rate of new chlamydia diagnoses?
How is it diagnosed?
352 per 100,000 population
It is the most common new STI diagnosis in the UK
It is diagnosed by genital swab
How long is the lifecycle of chlamydia?
48-72 hours
In what % of men and women is chlamydia asymptomatic?
50% of men and 80% of women
What are the symptoms of chlamydia?
- penile/vaginal discharge
- pelvic inflammatory disease
(pain and infertility)
- reactive arthritis
What are the symptoms of chlamydia in children?
- prematurity
- pneumonia
- conjunctivitis (blindness)
What are the 3 treatments for chlamydia?
- azithromycin
- erythromycin
- doxycycline
What is the overall rate of diagnoses of new cases of gonorrhoea?
How is it diagnosed?
62 per 100,000
It is diagnosed by genital swab
What is gonorrhoea caused by?
neisseria gonorrhoeae
what % of gonorrhoea cases are accounted for by MSM?
65%
In what % of men and women is gonorrhoea asymptomatic?
It is asymptomatic in 50% of women
It is symptomatic in 80% of men
What are the symptoms of gonorrhoea?
- urethral/vaginal discharge
2. pelvic inflammatory disease - infertility
What is the treatment for gonorrhoea?
Ceftriaxone injection
This is usually given with the treatment for chlamydia
What are the alternative names that have been used for AIDS?
GRID - gay-related immune deficiency
4H disease - homosexuals, heroin users, hemophiliacs, haitians
What did HIV virus evolve from?
Simian immunodeficiency virus
SIV
What is the difference between HIV 1 and HIV2?
HIV 1 originates in South Cameroon through the evolution of SIV(cpz)
HIV 2 originates in West Africa through the evolution of SIV(smm)
What are the 3 stages in the lifecycle of HIV and the enzymes involved?
- reverse transcriptase
- integrase
- protease
What is the role of reverse transcriptase?
It synthesises RNA into DNA
What is the role of integrase?
It integrates viral DNA into the host genome
What is the role of protease?
It cleaves the viral polyprotein
This leads to a viral protein that will leave the cell via budding
What is the initial “syndrome” experienced after primary HIV infection?
How long does it last?
Acute HIV syndrome
It involves wide dissemination of the virus and seeding of the lymphoid organs
Lasts from weeks 3-9 post-infection
How long does the clinical latency stage of HIV infection last for?
What happens once this stage ends?
Week 9 - Year 7 post infection
This then leads to symptoms of AIDS
What are the symptoms like at initial infection and during the latency period?
flu-like symptoms at initial infection
the latency period is asymptomatic
If HIV is untreated, how many years will it be until someone dies?
They will die after 11 years of being infected
If HIV is untreated, what are the AIDS-defining symptoms that result?
Immunodeficiency and opportunistic infections
What is the treatment for HIV and how does it work?
HAART
It acts as:
- fusion inhibitor
- reverse-transcriptase inhibitor
- integrase inhibitor
- protease inhibitor
This prevents replication of the virus
What is the recommendation given to pregnant women with HIV?
All women should be on HAART
They should not breastfeed
Under what conditions can a woman with HIV have a vaginal birth?
If viral load is < 50 HIV RNA at 36 weeks
What is the rate of diagnoses of syphilis?
What % of diagnoses are men?
10 per 100,000 population
94% of all cases are men, with the highest rate being men aged 25-34
How is syphilis diagnosed?
How has it increased over the last 10 years?
Diagnosed by blood test
Increased by over 600% in the last 10 years
What are the stages of syphilis infection?
- primary
- secondary
- latency
- tertiary
How does the primary stage of syphilis classicaly present?
A single chancre
This is a firm, painless, non-itchy skin ulceration
How does secondary syphilis present itself?
A diffuse rash which frequently involves the palms of the hands and soles of the feet
There may also be sores in the mouth or the vagina
How does latent syphilis present itself?
There are little to no symptoms
This phase can last for years
How does tertiary syphilis present itself?
- gummas - soft non-cancerous growths
- neurological symptoms
- heart symptoms
What is the treatment for syphilis?
It depends upon the stage of diagnosis
Often use penicillin
What are the general ways to reduce the risk of being infected with an STI?
- consistent and correct condom use
- reducing the number of sexual partners
- avoidance of overlapping sexual relationships
When should an STI screening programme be attended?
- annually
2. with a change of sexual partner
When are MSM recommended to have an HIV/STI screen?
Annually or every 3 months if having condom-less sex with new or casual partners
What organism causes chlamydia?
C. trachomatis
