STIs Flashcards
Name the pathogen that causes gonorrhoea
Neisseria gonorrhoeae
Clinical presentations of uncomplicated urogenital gonorrhoeae for males and females?
Males:
- Purulent urethral discharge
- Dysuria
- Urinary frequency
Females:
- Mucopurulent vaginal discharge
- Dysuria
- Urinary frequency
What are the clinical presentations of complications of gonorrhoea (if left untreated) for males, females and both?
Note: gonorrhoea is a disseminated disease!
Males:
- Epididymitis
- Prostatitis
- Urethral stricture
- Disseminated disease
Females:
- Pelvic inflammatory disease
- Ectopic pregnancy
- Infertility
- Disseminated disease
Both:
- Disseminated skin lesions, tenosynovitis, monoarticular arthritis
How is gonorrhoea diagnosed? (3)
- Gram-stain of genital discharge
- Culture
- NAAT
First-line for uncomplicated gonococcal infections?
What other infection must we treat it with?
**MUST also treat for chlamydial infection (unless it has been excluded)
IM ceftriaxone 500mg (for persons weighing < 150kg) (single dose)
PLUS
PO doxycycline 100mg bd x 7d (Anti-chlamydial Tx)
For uncomplicated gonococcal infections, if the first line is not available, what should we use instead?
IM gentamicin 240mg (single dose)
PLUS
PO azithromycin 2g (single dose)
Name the pathogen that causes chlamydia
Chlamydia trachomatis
What is the clinical presentation of chlamydia?
Similar to gonorrhoea but milder.
Like gonorrhoea, can infect various sites
How is chlamydia diagnosed?
NAAT
First-line Tx for chlamydia?
What is the alternative regimen?
First-line:
PO doxycycline 100mg bd x 7d
Alternative regimen:
PO azithromycin 1g (single dose)
OR
PO levofloxacin 500mg od x 7d
Is test of cure required for chlamydia?
No, unless pt is pregnant, non-adherent or s/sx persist.
Name the pathogen that causes syphilis
Treponema pallidum
How is syphilis diagnosed?
- Darkfield microscopy of exudates from lesions
- 2 serological tests → (1) Treponemal and (2) Non-treponemal test
Tx for syphilis: primary, secondary or early latent (<1 year duration)?
If penicillin allergic? + counselling?
IM benzathine penicillin G 2.4 million units x 1 dose
If penicillin allergic:
- PO doxycycline 100mg bd x 14d
⚠️Counselling: Take with food to reduce GI upset. Take with glass of water and maintain upright for at least 30 min to prevent heartburn. Do not take with milk, Ca or Fe, take 2hrs apart.
SEs: GI, photosensitivity
Tx for syphilis: late latent (> 1 year) or unknown duration or tertiary?
If penicillin allergic? + counselling?
IM benzathine penicillin G 2.4 million units oiw x 3 doses
If penicillin allergic:
PO doxycycline 100mg bd x 28d
⚠️Counselling: Take with food to reduce GI upset. Take with glass of water and maintain upright for at least 30 min to prevent heartburn. Do not take with milk, Ca or Fe, take 2hrs apart.
SEs: GI, photosensitivity
Tx for neurosyphilis?
If penicillin allergic? (special case: what should we do in addition?)
(1) IV crystalline penicillin G 3-4 million units q4h x 10-14d
OR
18-24 million units/d as continuous infusion x 10-14d
OR
(2) IM procaine penicillin G 2.4 million units daily
PLUS
PO probenecid 500mg qds x 10-14d
If penicillin allergic:
IV/ IM ceftriaxone 2g daily x 10-14d
(If concern for cross-sensitivity → skin test to confirm penicillin allergy, desensitise if necessary)
What normally happens 24h after syphilis Tx and what can we do about it?
Jarisch-Herxheimer reaction: acute febrile reaction, headache, myalgia
Antipyretics will help (but not prevent)
For syphilis, how often should we do quantitative VDRL or RPR?
At 3, 6, 12, 18, 24 months
What results should we see for VDRL or RPR to know that our syphilis Tx is successful?
Treatment successful if VDRL or RPR ↓ by at least fourfold (eg 1:64 to 1:16)
How often should we monitor CSF for neurosyphilis?
CSF examination every 6 months until CSF normal
How do you define Tx failure for syphilis? What should we do?
Tx failure if at 6 months:
- Shows s/sx of disease
- Failure of VDRL or RPR to ↓ by at least fourfold/ in fact ↑ 1:16 to 1:64
What to do:
- Retreat and re-evaluate for unrecognised neurosyphilis
Name the pathogen that causes genital herpes.
Which subtype causes genital herpes?
Herpes simplex virus (HSV-1 & HSV-2)
HSV-2 causes genital herpes
Is there any cure for genital herpes?
NO. It is a lifelong, chronic viral infection
Clinical presentation of genital herpes?
- Classical painful multiple vesicular or ulcerative lesions
- Local itching, pain, tender inguinal lymphadenopathy
- Flu-like symptoms (eg fever, headache, malaise) during first few days after appearance of lesions
- First infection usually more severe, lasts 2-3w
- Vesicles develop over 7-10 days, heal in 2-4w
Before recurrent genital herpes reappear, what are the prodromal s/sx?
- Mild burning, itching or tingling in ~50% of pts prior to recurrence of lesions
- S/sx less severe in recurrent disease (ie less lesions, heal faster, milder)
What tests can be used to diagnose genital herpes?
- Virologic tests (viral cell culture and NAAT)
- Serologic tests → type-specific (HSV-1 or HSV-2) but NOT useful for first episode infection as it takes 6-8w for Ab to reach detectable level
What are the 2 antivirals used for genital herpes?
Acyclovir [Zovirax]
Valacyclovir [Valtrex]
MOA of Acyclovir?
Inhibits viral DNA polymerase → inhibits DNA synthesis and replication
Tx regimen for genital herpes using acyclovir?
PO Acyclovir 400mg tds x 7-10d
OR
IV Acyclovir 5-10mg/kg q8h x 2-7d, complete WITH PO for total 10d (⚠️For severe diseases or complications that require hospitalisation)
What are some counselling points for genital herpes using acyclovir/ valacyclovir?
Take without regards to food, after food if GI upset. Maintain ADEQUATE HYDRATION to prevent recrystallisation in renal tubules.
SEs: malaise, headache, n/v/d
Tx regimen for genital herpes using valacyclovir?
PO 1g BD x 7-10d
What is the chronic suppressive Tx for genital herpes? (3)
(1) PO acyclovir 400mg bd
(2) PO valacyclovir 500mg od
(⚠️LESS EFFECTIVE than the others for pts with FREQUENT (≥10/ year) recurrences)
(3) PO valacyclovir 1g od
What type of patients need indefinite chronic suppression for genital herpes?
Usually immunocompromised pts with complicated disease course (eg disseminated encephalitis, meningitis, keratitis)
When do we take episodic Tx for genital herpes?
Requires initiation of Tx WITHIN 1 DAY of lesion onset/ during prodrome
Does episodic Tx for genital herpes help reduce risk of transmission?
No
Tx regimen for episodic Tx for genital herpes using Acyclovir?
PO Acyclovir 800mg bd x 5d
OR
PO Acyclovir 800mg tds x 2d
Tx regimen for episodic Tx for genital herpes using Valacyclovir?
PO Valacyclovir 500mg bd x 3d
OR
PO Valacyclovir 1g od x 5d
Advantage of episodic vs chronic suppressive Tx for genital herpes?
Episodic Tx is shorter duration and severity of s/sx, improved pt adherence and less costly.
What are the non-pharmacological Tx for genital herpes?
- Warm saline bath → relieves discomfort
- S/sx management → analgesia, anti-itch (eg hydrocortisone cream)
- Good genital hygiene to prevent superinfection
- Counselling regarding natural hx of infection
