STIs Flashcards
What is the most common STI in England?
Chlamydia
Why are older age groups also vulnerable to STIs?
May be less likely to see or engage with safer sex and sexual health messaging.
Why are high levels of gonorrhoea concerning?
Emergence of resistance or decreased susceptibility to antimicrobials used for treatment.
What type of infection is chlamydia?
Gram -ve bacteria
What are the 3 main types of chlamydia?
- Chlamydia trachomatis (most common)
- Chlamydia pneumoniae
- Chlamydia psittacci
C. pneumoniae and C. psittacci cause respiratory infections.
How can chlamydia be diagnosed?
Genital swab
Describe the life cycle of C. trachomatis
- The elementary body (EB), a small infectious particle found in secretions, enters a cell, such as an endocervical or urethral cell, to replicate.
- Within eight hours, the EB transforms into a reticulate body (RB), which begins to multiply within an isolated area called an inclusion.
- Within 24 hours, some RBs reorganise back to EBs, and, as the cell wall bursts, the EBs are released to infect adjacent cells or to be transmitted to and infect another person.
What are the symptoms of chlamydia in women?
- Asymptomatic in 80%
- Vaginal discharge
- Pelvic inflammatory disease (pain, infertility)
- Reactive arthritis
What are the symptoms of chlamydia in males?
- Asymptomatic in 50%
- Penile discharge
- Reactive arthritis
What are the symptoms of chlamydia in infants?
Prematurity, pneumonia, conjunctivitis (blindness)
What is the treatment for chlamydia?
Antibiotics:
- Azithromycin (recommended)
What type of infection is gonorrhoea?
Gram -ve bacteria
Neisseria Gonorrhoeae
How is gonorrhoea diagnosed?
Genital swab
What are the symptoms of gonorrhoea in men?
- Asymptomatic in 80% of men
- Urethral discharge
What is pelvic inflammatory disease (PID)?
Infection of female upper genital tract
1 in 10 women can become infertile
What are the symptoms of gonorrhoea in females?
- Asymptomatic in 50% of women
- Vaginal discharge
- PID, infertility
What is the treatment for gonorrhoea?
Ceftriaxone (injection)
Usually given with treatment for Chlamydia
How does HIV infect cells?
- HIV enters macrophages and CD4-positive T cells (CD4 is a glycoprotein receptor found on cells) by the adsorption of glycoproteins on its surface to receptors on the target cell
- Fusion of the viral envelope with the cell membrane
- The release of the HIV capsid into the cell.
What happens once HIV is released into cell?
- Reverse transcriptase is activated and transcribes RNA into complementary DNA.
- Viral DNA is integrated into the genome of the host cell.
- DNA can be transcribed into mRNA which direct the synthesis of viral proteins (translation).
What are the initial symptoms of HIV?
Flu like illness but often have a latency period that is asymptomatic
When does HIV progress to AIDS?
Eventually, if untreated, immunodeficiency results and opportunistic infections.
What is the treatment for HIV?
HAART (highly active antiretroviral therapy)
What is HAART?
A treatment regimen typically comprised of a combination of three or more antiretroviral drugs.
How are pregnant women with HIV treated? What care must be taken during childbirth?
- All women should be on HAART
- Can have a vaginal birth if viral load <50 HIV RNA at 36
weeks. (LSCS if viral load >50) - Should not breastfeed.
What type of infection is syphilis?
Bacteria
How does syphilis spread?
The disease starts as a painless sore — typically on your genitals, rectum or mouth. Syphilis spreads from person to person via skin or mucous membrane contact with these sores.
How is syphilis diagnosed?
Blood test
What are the stages of syphilis?
Primary, secondary, latent, tertiary
Describe the primary stage of syphilis
Presents with a single chancre (a firm, painless, non itchy skin ulceration)
If untreated, 1ary develops to 2ary syphilis. What are the symptoms of 2ary syphilis?
A diffuse rash which frequently involves the palms of the hands and soles of the feet
Sores in the mouth or vagina
If untreated, 2ary can progress to latent syphilis. Describe this stage
Little to no symptoms (dormant) which can last for years
What is tertiary syphilis?
Gummas (soft non-cancerous) growth will invade and damage organs, neurological and heart problems
What is the treatment for syphilis?
Depends upon stage at diagnosis but can be cured completely
Penicillin
How can you 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
Partner notification
When should you be screened for STI?
- Change of sexual partner
- Annually
MSM:
- HIV and STI screen annually, or every 3 months if having condom-less sex with new partners
Which STI has the highest rate of new diagnosis in the UK?
Chlamydia
Which age group is most at risk of acquiring an STI?
20-30
Which organism causes Chlamydia?
C. trachomatis
What treatment is advised following the detection of gonorrhoea?
Ceftriaxone and Azithromycin
