Sexually Transmitted Infections

What are rates of STI by gender and age?

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What is most common STI in UK?

• chlamydia 

Why are there high rate of STIs in younger population?

• cognitive factors

  • reduced reasoning/ judgement capacity

  • difficulty in planning head

• behavioural factors

  • less likely to use condoms

  • more likely to have multiple partners

  • more likely to engage in substance use = riskier sexual practices

Why are younger females more biologically susceptible to becoming infected upon exposure to STIs?

• cervical ectopy

• decreased local immunity in genital tract

• a smaller introitus (vaginal opening) and lack of lubrication can lead to traumatic sex

What types of males are more susceptible to STI?

• uncircumcised males 

  • (phimosis = foreskin of penis cannot be fully retracted over head of penis)

What is phimosis?

• foreskin of penis cannot be fully retracted over head of penis

If you have high sensitivity what does it mean?

• ruled out if person tests negative (SNout = sensitivity, negative out)

If you have high specificity what does it mean?

• ruling in a disease if peron tests positive (SpPin specificity, positive, rule in)

What is chlamydia trachomatis?

• small gram -ve bacilli with no peptidoglycan layer in cell wall

• Exists in two forms

  • Elementary body (infective form)

  • Reticulate body (non-infectious form)

What are the 2 forms of chlamydia trachomatis?

How does chlamydia trachomatis infect a cell?

• elementary body (infective form)

• Reticulate body (non-infectious form)

• (Add slide 18 pic)

  

What are symptoms of C trachomatis?

• majority are asymptomatic

• May cause a mucopurulent cervicitis in females and urethritis in males

What can ascending infection of chlamydia result in for males and females?

• pelvic inflammatory disease (PID) in women

• Epididymitis in men

What tests can be used to diagnose chlamydia?

• urethra swab, rectal swab

• Cervical swab, midstream urine sample

What was first line treatment of chlamydia in 2018?

• 1g of azithromycin OD

What is treatment of chlamydia post-2018?

• doxycycline 100mg bd for 7 days (contraindicated in pregnancy)

• Azithromycin 1g OD, followed by 500mg OD for 2 days

• Also can take erythromycin or ofloxacin (contraindicated in pregnancy)

• Abstain from all forms of sex during treatment

What is common symptoms of gonorrhoeae?

• mucopurulent urethritis, dysuria (males)

• Vaginal discharge, dysuria, dyspareunia and lower abdominal pain (females)

What is treatment for gonnorhoeae?

• 1g ceftiaxone IM as a single dose

• 500mg ciprofloxacin as a single dose

What is anogenital warts (condyloma) caused by?

How is it spread?

• human papilloma viruses

• through skin to skin contact or using a sex toy after someone else (indirect)

What HPV causes 90% of condyloma (anogenital warts)?

• HPV 6 and 11

What type of anogenital warts can be treated?

What is used to treat condyloma (anogenital warts)?

• external visible warts

• if less than 4 square cm surface with warts then topical preparation podophyllotoxin used

  • Four treatment cycles of BD application for 3 days followed by 4 day rest

• Imiquimod for refractory cases (3x a week for up to 16 weeks)

• Cryotherapy or electrocautery

What causes anogenital herpes?

• HSV 1 or 2

• Transmitted via skin to skin contact or indirectly (e.g. sex toy)

What percentage of population will have HSV-1 by 30??

• 50%

What are symptoms of anogenital herpes?

• flu like symptoms and small blisters that burst to leave open sores

• Urinating can be painful

How do you diagnose anogenital herpes?

• diagnosis by sampling a blister using PCR

How do you treat anogenital herpes?

• 400mg aciclovir TDS for 5 days