STI

Question 1

which STI legally required to be reported upon diagnosis

Answer 1

gonorrhoea, non-gonococcal urethritis, syphilis, chlamydia, genital herpes, HIV/AIDS, viral hepatitis

Question 2

gonorrhoea general

Answer 2

1) causative organism

• neisseria gonorrhoea (intracellular gram neg diplococci)

2) mode of transmission

• sex, mother-to-child during childbirth

Question 3

diagnosis of gonorrhea

Answer 3

1) gram stain of genital discharge
2) culture
3) NAAT

Question 4

infectious site for gonorrhoea

Answer 4

urethritis, cervicitis, proctitis, pharyngitis, conjunctivitis, disseminated

Question 5

clinical presentation of gonorrhoea

Answer 5

• can be asymptomatic
• symptoms
  1) male: purulent urethral discharge
  2) female: mucopurulent vaginal discharge
  3) both: dysuria, urinary frequency
• complications
  1) male: epididymitis, prostatitis, urethral stricture
  2) female: pelvic inflammatory disease, ectopic pregnancy, infertility
  3) both: disseminated disease, skin lesion, tenosynovitis, monoarticular arthritis

Question 6

management of uncomplicated gonorrhoea

Answer 6

• X fluoroquinolone (resistance)
• gonococcal infection treatment + anti-chlamydia therapy (doxycycline) for concurrent treatment unless X chlamydia
• 1st line: ceftriaxone
• alternative: gentamycin + azithromycin

Question 7

chlamydia general

Answer 7

• causative agent: chlamydia trachomitis
• infect various site (similar to gonorrhoea)
• transmission: sex, mother-to-child

Question 8

diagnosis of chlamydia

Answer 8

NAAT

Question 9

clinical presentation of chlamydia

Answer 9

milder symptoms than gonorrhoea, similar complications to gonorrhoea

Question 10

treatment for chlamydia

Answer 10

• 1st line: doxycycline
• alternative: azithromycin (use 1st cuz adherence), levofloxacin

Question 11

management of sex partners for gonorrhea & chlamydia

Answer 11

• evaluate & treat sexual partner in last 60 days
• if last sexual exposure > 60 days then treat most recent partner
• if receiving treatment then abstain from sex 7 days after treatment (prevent transmission)
• abstain from sexual intercourse until all sexual partners treated (prevent reinfection)

Question 12

syphilis general

Answer 12

• causative organism: treponema pallidum
• transmission: sex, mother-to-child (transplacental)

Question 13

serological tests for syphilis

Answer 13

1) treponemal

• use treponemal antigen to detect treponemal activity
• confirmatory test cuz more sensitive & specific
• reactive for life X for monitoring response but if infected before

2) non-treponemal

• cardiolipin to detect treponemal antibodies
• types: VDRL slide test/RPR card test
• +ve test: any stage of syphilis
• quantitative test (measure response)

Question 14

treat primary/secondary/early latent syphilis

Answer 14

1) IM benzathine pen G 2.4 million units
2) pen allergy: PO doxycycline 100mg BD 14 days

• take w food
• take w water + upright position at least 30 mins
• X milk, divalent cation (2 hrs)
• SE: GI, photosensitivity

Question 15

treat late latent (> 1 yr)/unknown duration/tertiary syphilis

Answer 15

1) IM benzathine pen G 2.4 million units once a wk for 3 doses
2) pen allergy: PO doxycycline 100mg BD 28 days

Question 16

treat neurosyphilis

Answer 16

1) IV crystalline pen G (3-4 million units q4h | 18-24 MU/d as continuous infusion 10-14 days) or IV procaine pen G (2.4 MU daily) + PO probenecid (500mg qid) 10-14 days
2) pen allergy: IV/IM ceftriaxone 2g daily 10-14 days

• concern cross-sensitivity: skin test to confirm pen allergy, desensitise if required

Question 17

what is the function of PO probenecid in neurosyphilis treatment?

Answer 17

reduce secretion of penicillin = increase penicillin concentration in systemic

Question 18

monitoring for syphilis treatmtent response - JH reaction

Answer 18

• acute febrile reaction + headache, myalgia
• within first 24 hrs
• not preventable, can give antipyretics to help

Question 19

monitoring for syphilis treatment response - pri/secondary/latent

Answer 19

• quantitative VDRL or RPR 3, 6, 12, 18, 24 months
• treatment success if decrease of VDRL/RPR titre by at least fourfold
  ** lower antibody = lesser antibody titre (good) = body X producing antibody to fight antigen = little antigen

Question 20

monitoring for syphilis treatment response - neurosyphilis

Answer 20

CSF examination every 6 month until CSF normal

Question 21

syphilis management of sex partners

Answer 21

• all at risk sexual partners evaluated & tested
• X sex w new partners until all lesions healed

Question 22

genital herpes causative agents

Answer 22

herpes simplex virus (HSV-1, HSV2)

• HSV-2 cause recurrence

Question 23

cycle of HSV infection

Answer 23

1) primary mucocutaneous infection
2) infection of nerve ganglia
3) establishment of latency
4) reactivation
5) recurrent outbreak/flares

Question 24

route of transmission for HSV infection

Answer 24

1) body fluids
2) intimate skin-to-skin contact

Question 25

infection progress for HSV

Answer 25

1) Vesicles develop over 7 - 10 days 2) heal in 2-4 wks 3) intermittent viral shedding from epithelial cells

Question 26

clinical presentation of genital herpes

Answer 26

1) multiple painful vesicles (break to form ulcerative lesions) 2) local itching, pain, tender inguinal lymphadenopathy 3) flu-like symptoms - fever, headache, malaise first few days after appearance of lesions 4) prodromal symptoms - mild burning, itching, tingling - prior to appearance of recurrent lesion

Question 27

type-specific (HSV 1/2) serologic test

Answer 27

- Ab to HSV develop during first few wks after infection, persist indefinitely - X useful for first ep of infection cuz take 6-8 wks for serological detection - HSV-2 Ab = anogenital infection

Question 28

genital herpes supportive care

Answer 28

1) warm saline bath relieve discomfort 2) symptom management: analgesia, anti-itch 3) good genital hygiene to prevent superinfection 4) counselling

Question 29

MOA of antivirals for genital herpes

Answer 29

inhibit viral DNA polymerase -> inhibit DNA synthesis & replication

Question 30

types of antivirals for genital herpes

Answer 30

1) acyclovir - PO 400mg TDS 7-10 days - severe/complicaations that require hospitalisation: IV 10mg/kg q8h x 2-7 days + PO 10 days - hydration to prevent crystallisation in renal tubule 2) valacyclovir - PO 1g BD for 7-10 days

Question 31

pharmacological management of recurrent genital herpes

Answer 31

antiviral as chronic/suppressive therapy

Question 32

advantages of chronic suppressive therapy for genital herpes

Answer 32

- reduce frequency by 70-80% - X symptomatic outbreak = improve QoL - long term safety & efficacy - decrease risk of transmission + consistent condom use & abstinence

Question 33

disadvantages of chronic suppressive for recurrent genital herpes

Answer 33

$$$$$$, compliance

Question 34

chronic suppressive therapy regimen for genital herpes

Answer 34

- acyclovir 400mg PO BD - valacyclovir 500mg PO OD - valacyclovir 1g PO OD - when indefinite suppression indicated: ** complicated disease course (disseminated disease: encephalitis, meningitis, keratitis) ** immunocompromised host

Question 35

advantages of episodic treatment for genital herpes

Answer 35

1) Shorten duration & severity of symptoms 2) cheaper 3) more likely to be compliant

Question 36

disadvantages of episodic treatment for genital herpes

Answer 36

1) require indication of therapy within 1 day of lesion onset or during prodromal that precedes some outbreaks 2) X reduce risk of transmission

Question 37

possible meds for episodic treatment for recurrent genital herpes

Answer 37

- acyclovir 800mg oral BD 5 days - acyclovir 800mg TID for 2 days - valacyclovir 500mg oral BD 3 days - valacyclovir 1g oral OD 5 days