Sexually Transmitted Infections

Question 1

What are the modes of transmission of STIs?

Answer 1

1. Sexual contact with an infected person
2. Direct contact of broken skin with open sores, blood, or genital discharge
3. receiving contaminated blood
4. mother to child during pregnancy (syphilis, HIV), childbirth (chlamydia, gonorrhoea), or breastfeeding (HIV)

Question 2

What are the risk factors for STI?

Answer 2

• unprotected sexual intercourse
• illicit drug use
• multiple sex partners / sexual contact with people who have multiple sex partners
• prostitution
• men who have sex with men

Question 3

What are the prevention methods for STI?

Answer 3

• abstinence and reduction in sexual partners
• use male condoms
• avoid drug use and sharing needles
• vaccinations: HepB, HPV
• pre and post exposure prophylaxis: HIV

Question 4

What bacteria causes gonorrhoea?

Answer 4

neisseria gonorrhoeae

Question 5

How is gonorrhoea diagnosed?

Answer 5

gram-stain and culture of genital discharge, nucleic acid amplification test (PCR)

Question 6

What are the symptoms of gonorrhoea?

Answer 6

purulent urethral / vaginal discharge, dysuria, urinary frequency

Question 7

What is the first-line treatment of gonorrhoea?

Answer 7

IM ceftriaxone 500mg single dose (for pt >= 150kg, use 1g)

Question 8

What is the alternative treatment for gonorrhoea?

Answer 8

IM gentamicin 240mg + PO azithromycin 2g single dose

Question 9

Is test of cure recommended for gonorrhoea?

Answer 9

Yes

Question 10

How should sexual partners of patients with gonorrhoea be managed?

Answer 10

• Evaluate all sexual partners in the last 60 days / last sexual partner if > 60 days
• Abstain from sex for 7 days after treatment
• Abstain until all partners have been treated (minimise risk of reinfection)

Question 11

What bacteria causes chlamydia?

Answer 11

chlamydia trachomatis

Question 12

What is the first-line treatment regimen for chlamydia?

Answer 12

PO doxycycline 100mg BD x 7d

Question 13

What are the alternative regimens for chlamydia?

Answer 13

PO azithromycin 1g single dose
PO levofloxacin 500mg OD x 7d

Question 14

How should sexual partners of patients with chlamydia be managed?

Answer 14

• Evaluate all sexual partners in the last 60 days / last sexual partner if > 60 days
• Abstain from sex for 7 days after treatment / after completion of treatment
• Abstain until all partners have been treated (minimise risk of reinfection)

Question 15

What bacteria causes syphilis?

Answer 15

treponema pallidium

Question 16

What are the treponemal tests for syphilis?

Answer 16

TPHA, TPPA

Question 17

How should the treponemal tests for syphilis be used?

Answer 17

as confirmatory tests
should not be used as monitoring as they may remain reactive even with treatment

Question 18

What are the non-treponemal tests for syphilis?

Answer 18

RPR, VDRL

Question 19

How should the non-treponemal tests for syphilis be used?

Answer 19

used to monitor treatment, antibody titres correlate with disease activity

Question 20

What is the recommended treatment regimen for primary, secondary, and early latent syphilis?

Answer 20

IM Benzylpenicillin 2.4 MU single dose

Question 21

What is the recommended treatment regimen for primary, secondary, and early latent syphilis, for pt with penicillin allergy?

Answer 21

PO doxycycline 100mg BD x 14d

Question 22

What is the recommended treatment regimen for late latent (> 1yr), tertiary, and unknown duration syphilis?

Answer 22

IM Benzylpenicillin 2.4 MU once a week x 3 doses

Question 23

What is the recommended treatment regimen for late latent (> 1yr), tertiary, and unknown duration syphilis for pt with penicillin allergy?

Answer 23

PO doxycycline 100mg BD x 28d

Question 24

What is the recommended treatment regimen for neurosyphilis?

Answer 24

Crystalline penicillin 4 MU Q4H OR 18-24 MU / day, continuous infusion x 10-14d OR
IM procaine penicillin 2.4 MU OD + PO probenecid 500mg QDS x 10-14d

Question 25

What is the recommended treatment regimen for neurosyphilis, for pt with penicillin allergy?

Answer 25

IV/IM ceftriaxone 2g OD x 10-14d

Question 26

What is the monitoring for primary, secondary, and latent syphilis?

Answer 26

Quantitative VDRL / RPR every 3, 6, 12, 18, 24 months success = decrease by 4-fold

Question 27

What is the monitoring for neurosyphilis?

Answer 27

CSF exam every 6m until normal

Question 28

What defines treatment failure in syphillis?

Answer 28

at 6 months, still have symptoms / failure to decrease antibody titer by 4-fold

Question 29

What is the Jarisch-Herxheimer reaction?

Answer 29

fever in the first 24H of treatment

Question 30

What pathogen causes genital herpes?

Answer 30

HSV 1 and HSV 2 (more common)

Question 31

How is genital herpes transmitted?

Answer 31

transfer of bodily fluids / intimate skin contact

Question 32

What is the clinical presentation of genital herpes?

Answer 32

- classical painful multiple vesicular / ulcerative lesions that develop over 7-10 days and heal in 2-4 weeks - local itching, pain, tender, inguinal lymphadenopathy - flu-like symptoms during the first few days after appearance of lesions - prodromal symptoms (mild burning, itching, tingling) prior to appearance of recurrent lesions - less severe in recurrent disease

Question 33

How is genital herpes diagnosed?

Answer 33

- pt history, previous contact with similar lesions - symptoms - virologic tests: viral cell culture and PCR of HSV DNA from lesions

Question 34

Are type-specific serologic tests used in the diagnosis of genital herpes in the first episode?

Answer 34

no, it takes 6-8w to be detectable

Question 35

What are the supportive care strategies for genital herpes?

Answer 35

- warm saline bath - good genital hygiene - anti-itch - analgesia - counselling on natural history of the disease

Question 36

What are the recommended treatment regimens for 1st episode genital herpes (non-severe)?

Answer 36

- PO acyclovir 400mg TDS x 7-10d - PO valacyclovir 1g BD x 7-10d

Question 37

What are the recommended treatment regimens for 1st episode genital herpes (severe)?

Answer 37

IV acyclovir 5-10mg/kg Q8H x 2-7d (continue with PO for a total of 10 days)

Question 38

What are the recommended treatment regimens for recurrent genital herpes (chronic suppressive therapy)?

Answer 38

PO acyclovir 400mg BD PO valacyclovir 500mg OD (not for those with many recurrent episodes) PO valacyclovir 1g OD

Question 39

What are the recommended treatment regimens for recurrent genital herpes (episodic therapy)?

Answer 39

PO acyclovir 800mg BD x 5d PO acyclovir 800mg TDS x 2d PO valacyclovir 500mg BD x 3d PO valacyclovir 1g OD for 5d