STD, HSV & VSV Flashcards
Name three bacterial STIs & their corresponding causative bacteria.
Syphilis: Treponema pallidum
Gonorrhoea: Neiserria gonorrhoeae
Non-gonococcal urethritis: Chlamydia trachomatis
Name two viral STIs & their corresponding causative virus.
Ano-genital herpes: Herpes simplex virus (HSV)
HIV/AIDS infection: Human immunodeficiency virus type 1 & 2 (HIV)
Name a fungal STI & its corresponding causative fungus.
Vaginal candidiasis: Candida albicans
Describe the mode of transmission for STIs.
Primarily by sexual contact w/ infected individual
Direct contact of broken skin w/ open sores, blood or genital discharge
Receiving contaminated blood from infected individuals
Vertical transmission from infected mother to child during:
- Pregnancy: syphilis, HIV
- Childbirth: chlamydia, gonorrhoea, HSV
- Breastfeeding: HIV
STIs can be contracted through dry kissing. True or false?
False.
However, some STIs can be transmitted through deep, wet kissing. Syphilis, gonorrhoea, chlamydia and herpes may be present in the mouth/throat of infected persons.
A person can be infected by more than one STI. True or false?
True.
Possible and not uncommon; always important to be tested for other STIs if an individual has already been diagnosed with one.
STIs are inheritable from parents to children. True or false?
False.
STIs are acquired infections; they are not inherited. However, mothers with STIs can pass on their infection to the baby during pregnancy, delivery or breastfeeding.
What are some risk factors associated with STIs?
1) Unprotected sexual intercourse
2) Number of sexual partners:
- Increased no. of sexual partners increases risk of acquiring & transmitting STIs
- Sexual contact with an individual who has multiple sexual partners are at risk as well
3) MSM (man-to-man sexual intercourse)
4) Prostitution / Commercial sex workers
5) Illicit drug use
What are some individual prevention methods one can adopt to minimise the risk of acquiring STDs?
1) Abstinence of sexual intercourse
2) Be faithful to an uninfected partner w/ long-term monogamous relationship
- i.e. Reduce number of sexual partners
3) Condom / Barrier contraceptive methods
- Note oral contraceptives are NOT able to prevent STDs!!
4) Avoid drug abuse & sharing of needles
5) Pre-exposure vaccinations (HPV, Hep B & Hep A)
6) Pre- & post-exposure prophylaxis (HIV)
Why is the management & prevention of STDs important?
1) To reduce related morbidity, progression to complicated disease (HIV/AIDS)
- some STDs are lifelong diseases & can impact QOL!
2) To prevent HIV infection
- Increased risk of HIV transmission / acquisition in pt. w/ genital herpes, gonococcal or syphilis infections
3) To prevent serious complications in women
- STDs are main preventable causes to infertility
- Prevention of HPV reduces risk of cervical cancer
4) To protect babies
- Untreated STIs are associated w/ congenital & perinatal infections in neonates, premature deliveries & neonatal deaths / stillbirth.
How is gonorrhoea diagnosed?
Intracellular gram-negative stain of diplococci in genital discharge or cultures or NAAT (e.g PCR)
Describe the clinical presentation of pt w/ gonorrhoea / chlamydia STIs.
Infected individuals may be asymptomatic.
Symptoms of uncomplicated urogenital gonorrhoea include:
M: purulent urethral discharge, dysuria, urinary frequency
F: mucopurulent vaginal discharge, dysuria, urinary frequency
What are some complications of untreated gonorrhea / chlamydia STIs?
M: urethral stricture, epididymitis, prostatitis, disseminated disease
F: pelvic inflammatory disease, ectopic pregnancy, infertility, disseminated disease
Disseminated (both): skin lesions, tenosynovitis (joint infections), monoarticular arthritis
What is the first-line Tx recommendation for a patient w/ uncomplicated urogenital gonorrhoea?
< 150kg: Ceftriaxone 500mg IM single dose
>= 150kg: Ceftriaxone 1g IM single dose
If chlamydia infection is NOT excluded:
Add doxycycline 100mg PO BD x 7 days
Alternative if ceftriaxone is not available:
Gentamicin 240mg IM single dose AND Azithromycin 2g PO single dose
- Due to significant gonorrhoea resistance against azithromycin
Test of cure from gonorrhoea is required. True or false?
False! Test of cure is NOT required unless symptoms persist (i.e. re-infection NOT Tx failure)
What are some counselling points pertaining to the management of sexual partners during Abx Tx of gonorrhoea?
1) Sexual partners in the last 60 days should be evaluated & treated. If last sexual exposure > 60 days, the most recent partner is to be treated.
2) To minimise disease transmission, pt. should abstain from sexual activity for 7 days after ceftriaxone Tx (w/ symptoms resolution).
- If pt is on doxycycline for chlamydia infection, abstain from sexual activity during 7 days of Tx (w/ symptoms resolution).
3) To minimise risk of reinfection, pt should abstain from sexual intercourse until ALL partners have been treated.
What is the first-line Tx recommendation for a patient w/ chlamydia STIs?
Doxycycline 100mg PO BD x 7 days
Alternative if doxycycline is not available:
Azithromycin 1g PO single dose
- if adherence is a concern
OR Levofloxacin 500mg PO OD x 7 days
Test of cure from chlamydia STIs is not required unless symptoms persist. True or false?
True.
What are some counselling points pertaining to the management of sexual partners during Abx Tx of STIs?
1) Sexual partners in the last 60 days should be evaluated & treated. If last sexual exposure > 60 days, the most recent partner is to be treated.
2) To minimise disease transmission, pt. should abstain from sexual activity for 7 days after single-dose therapy (w/ symptoms resolution) or until completion of a 7-day regimen w/ symptoms resolution if present.
3) To minimise risk of reinfection, pt should abstain from sexual intercourse until ALL partners have been treated.
How is chlamydia STI diagnosed?
Nucleic acid amplification tests (NAAT) or antigen detection
Which two types of serological tests must be used, in conjunction with darkfield microscopy of lesion exudates, to diagnose whether an individual has a syphilis infection?
Diagnosis requires darkfield microscopy of exudates from lesions & both of the following tests:
1) Treponemal test (confirmatory):
- uses treponemal Ag to detect treponemal Ab
- e.g. T. pallidum haemagglutination test (TPHA), T. pallidum passive particle agglutination assay (TPPA)
- more sensitive & specific than non-treponemal tests
- pt. may remain reactive for life, thus NOT used for monitoring for response to Tx
2) Non-treponemal test (response monitoring & screening tool):
- uses non-treponemal Ag (cardiolipin) to detect treponemal Ab
- e.g. of non-interchangable tests: Veneral Disease Research Laboratory (VDRL) slide test, rapid plasma reagin (RPR) card test
- +ve quantitative results indicate presence of ANY stage of syphilis; i.e. most dilute serum concentration w/ +ve reaction (1:16 positive -> 1:32 no reaction seen)
- Ab titres correlate to disease activity, thus used as Tx response monitoring tool BUT must use SAME test throughout!!
- Non-treponemal test titres usually decline after Tx & become non-reactive w/ time
- Less specific, thus can be used as screening tool; MUST be confirmed by treponemal test
Describe the clinical presentation of primary stage syphilis.
Single painless ulcer / chancre at site of infection but can also present w/ multiple, atypical or painful lesions
- Site of infection: external genitalia, perianal region, mouth, throat
- Heals spontaneously in 1-8 weeks
Describe the clinical presentation of secondary stage syphilis.
Skin rash, mucocutaneous lesions & lymphadenopathy
- Multisystem involvement due to haematogenous & lymphatic spread
- Develops 2-8 weeks after initial infection in untreated / inadequately treated individual
- Disappears in 4-10 weeks if untreated
Describe the clinical presentation of latent stage syphilis.
Early latent = < 1 year from initial infection
Late latent = > 1 year from initial infection
Asymptomatic but picked up by serological testing
- Possible multisystem involvement as internal organs continue to be affected by infection
- Develop 4-10 weeks after secondary stage in untreated / inadequately treated individual
Describe the clinical presentation of tertiary stage syphilis.
Can present with gummatous lesions in joints leading to impaired movement; cardiac involvement leading to heart, aortic insufficiency
- Possible multisystem involvement of heart, eyes, bones & joints
- Develop in approx. 30% of untreated / inadequately treated individual 10-30 years after initial infection
Describe the clinical presentation of neurosyphilis.
Cognitive dysfunction, motor or sensory deficits, ophthalmic or auditory symptoms, signs & symptoms of meningitis, stroke etc.
- CNS involvement can occur at any stage of syphilis
A positive VDRL test is sufficient to diagnose a patient with syphilis. True or false?
False!
Indicates presence of T. pallidum BUT must be confirmed with treponemal test (TPHA or TPPA)
What is the recommended Tx for a patient presenting signs & symptoms of primary syphilis?
For primary, secondary & early latent syphilis:
IM benzathine penicillin G 2.4 MU single dose
If penicillin allergy: PO doxycycline 100mg BD x 14 days
What is the recommended Tx for a patient presenting signs & symptoms of tertiary syphilis?
For unknown, late latent & tertiary syphilis:
IM benzathine penicillin G 2.4 MU once a week x 3 doses
If penicillin allergy: PO doxycycline 100mg BD x 28 days
What is the recommended Tx for a patient presenting signs & symptoms of neurosyphilis?
1) IV crystalline penicillin G 3-4 MU q4h OR 18-24 MU OD as continuous infusion x 10-14 days OR
2) IM procaine penicillin G 2.4 MU OD + PO probenecid 500mg QDS x 10-14 days
If penicillin allergy: IV/IM ceftriaxone 2g q24h x 10-14 days
- Skin test to confirm penicillin allergy; desensitise if necessary
What are some monitoring parameters to look out for in the pharmacological management of syphilis pt.?
Safety: Jarisch-Herxheimer reaction
- acute febrile reaction frequently accompanied by HA, migraine & other symptoms w/in 24h of Tx
- Antipyretics will help BUT not prevent
Efficacy: using quantitative VDRL / RPR titre
Primary & Secondary: 6 & 12 months from Tx initiation
Latent & Tertiary: 6, 12 & 24 months from Tx initiation
Neurosyphilis: CSF examination q 6 month until normal CSF
What is considered as treatment success or failure when using VDRL or RPR tests to monitor Tx response of syphilis pt.?
Success:
Decrease in VDRL or RPR titre by at least fourfold (e.g. 1:64 to 1:16)
Failure:
- shows signs & symptoms of disease
- failure to decrease in VDRL or RPR titre by at least fourfold OR increase (e.g. 1:16 to 1:64)
- retreat & re-evaluate for unrecognised neurosyphilis
Varicella-zoster virus and herpes simplex virus 3 are nonsynonymous with each other. True or false?
False.
Common name of HSV type 3 is VSV
Which type of herpes zoster virus often causes cold sores?
HSV1
Which type of herpes zoster virus often causes genital herpes?
Generally HSV2, but may involve HSV1
Which type of herpes zoster virus often causes chickenpox?
VSV or HSV3
Describe the clinical presentation of a patient experiencing chickenpox.
Benign self-limiting illness resulting in diffuse vesicular rash across scalp, face, limbs & trunk (palms & soles are spared)
- can be severe in immunocompromised individuals
- groups of new lesions appear over 4-7 days
Fever starts in 1-2 days before rash appears & last for 4-5 days
- usually abates once rash has completely appear
Describe the mode of transmission for chickenpox.
Inhalation of infected droplets; respiratory transmission
Describe the mode of transmission for shingles.
Contact transmission
What are some major risk factors for herpes zoster / shingles?
Immunocompromised & increasing age
Describe the clinical presentation of a patient experiencing shingles.
Rash begins as papules -> vesicles -> pustules over 3-5 days & usually dries w/ crusting in 7-10 days.
Rash often preceded by tingling, itching or pain (or combination) for 2-3 days & may be continuous or episodic.
Post-herpetic neuralgia (10-50%) is a pain persisting after rash resolved for many months or even years.
What is the recommended antiviral treatment for chickenpox / shingles?
Start antiviral Tx w/in 24-48h of rash onset to reduce duration & severity of symptoms.
Either PO acyclovir 800mg five times daily x 7 days
Or PO valacyclovir 1g TDS x 7 days
Describe the mode of transmission of genital herpes.
Transfer of body fluids or intimate skin-to-skin contact
Briefly describe the pathogenesis of HSV infection.
Primary mucocutaneous infection -> infection of nerve ganglia -> establishment of latency -> reactivation -> recurrent outbreaks / flairs
Genital herpes cannot be transmitted if the patient remains asymptomatic. True or false?
False!
Shedding & transmission can still occur while being asymptomatic!
Describe the clinical presentation of a pt w/ genital herpes.
1) Classical painful multiple vesicular or ulcerative lesions
- vesicles develop over 7-10 days & heal in 2-4 weeks
2) Localised itching, pain, tender inguinal lymphadenopathy
3) Flu-like symptoms (e.g. fever, HA, malaise) during first few days of lesions appearance
4) Prodromal syndrome include burning, stinging & itching
5) Symptoms are less severe in recurrent disease
What are some diagnostic tests available to determine if pt. has genital herpes?
1) Virologic tests: viral culture tests, NAAT (e.g. PCR) for HSV DNA from genital lesions
2) Type-specific serologic tests:
- more useful for recurrent infection
- presence of HSV2 Ab implies anogenital infection
What are the therapeutic goals of Tx for genital herpes?
Reduce tranmission
Relieve symptoms
Shorten clinical course
Prevent complications & recurrences
What are some supportive care pt can adopt during Tx for genital herpes?
Warm saline bath relieves discomfort
Good genital hygiene to prevent superinfections
Counselling regarding natural history & lifelong risk
What are the benefits & limitations of antiviral Tx for genital herpes?
Benefits:
1) PO acyclovir & valacyclovir has proven to reduce viral shedding by 7 days, duration of symptoms by 2 days & time to heal for 1st episode by 4 days
2) Comparable efficacy between acyclovir & valacyclovir; choice dependent on cost and pt adherence
3) Max benefits when initiated at earliest stage (w/in 72h)
Limitations:
1) Does NOT prevent latency or affect frequency & severity of recurrent disease after discontinuation of drug
2) Topical antiviral offers minimal clinical benefits; used only for cold sores
What is the recommended antiviral treatment for 1st episode of genital herpes?
Either PO acyclovir 400mg TDS x 7-10 days
Or PO valacyclovir 1g BD x 7-10 days
If severe / hospitalised: IV acyclovir 5-10mg/kg q8h x 2-7 days & complete with PO for a total of 10 days
Extend Tx duration if healing is incomplete.
What is the mechanism of action for acyclovir & valacyclovir?
Valacyclovir is a L-valine ester of acyclovir.
Both inhibit the viral DNA polymerase & thus inhibit DNA synthesis & replication.
What are some counselling points to provide for patients on acyclovir / valacyclovir?
Take w/o regards to food, after food if GI upset.
For IV therapy: Maintain adequate hydration to prevent crystalluria
SE for acyclovir: Malaise, headache, N/V/D
SE for valacyclovir: Headache
What are the recommended antiviral treatments for recurrent genital herpes?
1) Chronic Suppressive Therapy (either/or):
- Acyclovir PO 400mg BD
- Valacyclovir PO 1g OD
- Valacyclovir PO 500mg OD (< 10 episodes/year ONLY)
2) Episodic Therapy (either/or):
- Acyclovir PO 800mg BD x 5 days
- Acyclovir PO 800mg TDS x 2 days
- Valacyclovir PO 500mg BD x 3 days
- Valacyclovir PO 1g OD x 5 days
What are the benefits & limitations of chronic suppressive antiviral therapy for recurrent genital herpes?
Benefits:
1) Reduce frequency of recurrences by 70-80% in pt w/ > 6 recurrences/year
2) No symptomatic outbreaks -> improved QOL
3) Established long-term safety & efficacy
4) Decrease transmission risk w/ consistent condom use & abstinence during recurrences
Limitations:
1) Cost
2) Compliance
What are the benefits & limitations of episodic antiviral therapy for recurrent genital herpes?
Benefits:
1) Shorten duration & severity of symptoms
2) Less costly vs chronic suppression
3) Increased compliance
Limitations:
1) Requires initiation w/in 1 day of lesion outbreak or during prodrome
2) Does not reduce transmission risk
What are some non-pharmacological counselling points with pt with HSV infection?
- Educate natural Hx of disease
- Encourage to inform current & future sexual partners
- Sexual transmission of HSV can occur during asymptomatic periods
- Should abstain from sexual activity w/ uninfected partners when lesions or prodromal symptoms are present
- Risk of HSV sexual transmission is reduced w/ daily use of valacyclovir or acyclovir by infected pt.
- Latex condoms, when used consistently & correctly, may reduce risk of genital herpes transmission
- Neonatal HSV infection risk
- Increased HIV acquisition risk
How should the sexual partner of a patient infected with genital herpes be managed?
1) Symptomatic sexual partners should be evaluated & treated in the same manner as symptomatic pt w/ genital herpes.
2) Asymptomatic sexual partners of pt w/ genital herpes should be questioned concerning Hx of genital lesions & offered type-specific serological testing for HSV-2.
The use of only one type of serologic test (nontreponemal or treponemal) is sufficient for the diagnosis of syphilis. True or false?
False!
Both treponemal & non-treponemal tests must be used together for the diagnosis of syphilis.
- Use of only one type of serological test can result in false-negative results among persons tested during primary syphilis and false-positive results among persons without syphilis or previously treated syphilis.
