STDs Flashcards
What are the STDs that can be caused by bacteria? Virus?
Bacteria: Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum
Virus: herpes simplex virus 1
What are the modes of transmission of STDs?
Via sexual contact with infected persons
By direct contact of broken skin with open sores, blood or genital discharge
By receiving contaminated blood products
From an infected mother to her child during pregnancy, childbirth or breastfeeding
What are the risk factors for STDs?
unprotected sexual intercourse, number of sexual partners, prostitution, MSM, illicit drug use
What are individual prevention methods of STDs?
Abstinence and reduction of number of sexual partners barrier contraceptive methods avoid drug abuse and needles sharing Pre-exposure vaccination pre- and post-exposure prophylaxis
How is gonorrhea transmitted?
Sexual contact, mother-to-child during childbirth
What are the sites that gonorrhea can cause infection?
Urethra, cervix, rectal area, eyes, pharyngeal area, disseminated
How to diagnose gonorrhea?
Gram stain of genital discharge (pink diplococci, tend to invade neutrophils)
Culture
NAAT
What are the symptoms of uncomplicated urogenital gonorrhea?
Purulent urinary/vaginal discharge, dysuria, urinary frequency
Which STDs may lead to infertility?
Gonorrhea, chlamydia
When do we use dual antibiotics therapy in the treatment of gonorrhea?
When chlamydial infections has not been excluded
What is the first line for management of uncomplicated urogenital gonococcal infections?
Ceftriaxone 500mg IM single dose and doxycycline 100mg 2x/daily for 7 days if chlamydia is not ruled out
What are the alternative treatments for management of uncomplicated urogenital gonococcal infections?
Gentamicin 240 mg IM in a single dose AND azithromycin 2g orally in a single dose OR cefixime 800mg orally in a single dose
- if we give gentamicin and arithromycin, no need to add doxycycline
If chlamydia has not been excluded, treat for chlamydia with doxycycline 100mg 2x/daily for 7 days
Management of sexual partners in gonorrhea
- Sex partners in the last 60 days should be evaluated and treated. If last sexual exposure > 60 days, the most recent partner to be treated
- To minimise disease transmission, persons treated for gonorrhea should be instructed to abstain from sexual activity for 7 days after treatment
- To minimise risk for reinfection, patients also should be instructed to abstain from sexual intercourse until all their sex partners have been treated
How is chlamydia transmitted?
Sexual contact, mother-to-child during childbirth
Management of chlamydia
First line: doxycycline 100mg 2x/day for 7 days
Alternatives: azithromycin 1g single dose
Levofloxacin 500mg orally once daily for 7 days
When is it suitable to give levofloxacin in the treatment of a patient without exclusion of chlamydia co-infection with gonorrhea?
Ceftriaxone with levofloxacin, when the patient is unable to take both doxycycline and azithromycin
Management of chlamydia infection
- Sex partners in the last 60 days should be evaluated and treated. If last sexual exposure > 60 days, the most recent partner to be treated
- To minimise disease transmission, persons treated for chlamydia should be instructed to abstain from sexual intercourse for 7 days after single-dose therapy, or until completion of a 7-day regimen and resolution of symptoms if present
- To minimise risk for reinfection, patients also should be instructed to abstain from sexual intercourse until all their sex partners have been treated
What bacteria causes gonorrhea?
Neisseria gonorrhoeae
What bacteria causes chlamydia?
Chlamydia trachomatis
What bacteria causes syphilis?
Treponema pallidum
How is syphilis transmitted?
Sexual contact, mother-to-child (transplacental during pregnancy)
How is syphilis diagnosed?
Darkfield microscopy of exudates from lesions (look for spirals)
Requires 2 serological tests - treponemal and non-treponemal tests
When can secondary syphilis develop?
If primary syphilis heals spontaneously in 1-8 weeks and patient does not seek treatment
When can latent syphilis develop?
If secondary syphilis heals spontaneously in 4-10 weeks and patient does not seek treatment
What are the symptoms of primary syphilis?
Single painless ulcer but can also present with multiple, atypical or painful lesions
What is the site of infection of primary syphilis?
External genitalia, perianal region, mouth, throat
What is the site of infection of secondary syphilis?
Multisystem involvement due to hematogenous and lymphatic spread
What are the symptoms of latent syphilis?
Asymptomatic
What are the symptoms of secondary syphilis?
Skin rash, mucocutaneous lesions, lymphadenopathy
What are the symptoms of tertiary syphilis?
Can present with gummatous lesions in joints leading to impaired movement; cardiac involvement leading to heart-aortic insufficiency
What is neurosyphilis?
It is the CNS involvement of syphilis that can occur at any stage
What test is used to confirm syphilis?
What does it use?
Treponemal tests - uses treponemal antigen to detect treponemal antibody
What are the 2 different tests used for nontreponemal tests?
VDRL slide test
RPR card test
What antigen is involved in the treponemal test and nontreponemal test?
Treponemal test: treponemal antigen
Nontreponemal test: cardiolipin (nontreponemal antigen) to detect treponemal antibodies
If the result of VDRL/RPR is 1:16 positive, what does this imply?
It refers to the most dilute concentration that has a positive reaction. 1:32 will have no reaction seen.
Why is VDRL/RPR used to monitor treatment response?
Antibody titres correlate with disease activity hence used as a tool to monitor response to treatment
What is the treatment regimen for primary, secondary or early latent syphilis?
IM Benzathine 2.4 million units x single dose
penicillin allergic: PO doxycycline 100mg bid x 14 days
What is the treatment regimen for late latent or unknown duration or tertiary syphilis?
IM benzathine 2.4 million units once a week x 3 doses
Penicillin allergic: PO doxycycline 100mg bid x 28 days
Neurosyphilis dosing
IV crystalline penicillin G 3-4MU q4h or 18-24MU/d as continuous infusion x 10-14 days
IM procaine penicillin G 2.4 mu daily PLUS probenicid 500mg qid x 10-14 days
Penicillin allergic: IV/IM ceftriaxone 2g daily x 10-14 days
What is the monitoring for therapeutic response for syphilis?
Jarisch-Herxheimer reaction
Primary/secondary: VDRL or RPR at 6 and 12 months. Treatment success = decrease of CDRL or RPR titre by at least fourfold
Latent: 6, 12 and 24 months
Neurosyphilis: CNS examination every 6 month until CSF normal
What is defined as treatment failure at 6 months?
Shows signs and symptoms of disease or
failure to decrease VDRL or RPR titre by fourfold OR increase
Management of sexual partners
o Sexual partners should be evaluated for STIs and treated if tested positive
o Patients should be instructed to abstain from sexual intercourse until they and their sexual partners have completed treatment
o Abstinence should be continued until 7 days after a single-dose regimen or after completion of a 7-day regimen and resolution of symptoms, if present.
What is another name of HHV 3?
Varicella-zoster virus
How is HSV-1 spread?
through contact (often saliva)
What types of infection does VZV cause?
Chickenpox (Varicella) and shingles (herpes zoster)
What is the pain that persists after shingles rash has resolved called?
Post-herpetic neuralgia
Must an individual be symptomatic in order to transmit genital herpes to another person?
No, shedding of epithelial cells can occur during asymptomatic periods and transmit the infection
How is genital herpes diagnosed?
Patient history, presentation, symptoms, virologic tests, type-specific serologic tests
What does the presence of HSV-2 antibody imply?
Anogenital infection
Antibodies take a while to be produced after an initial infection, but once it is produced it is always there
Supportive care for genital herpes
Warm saline bath
Education about natural history of disease
Good genital hygiene to prevent superinfection (from scratching)
What is the mechanism of action of acyclovir
viral DNA polymerase inhibitor, inhibits DNA synthesis and replication
What is a key counselling point for acyclovir?
Maintain adequate hydration to prevent crystallisation in renal tubules
What are the options for patients with recurrent genital herpes?
Chronic suppressive therapy or episodic therapy
Does episodic therapy reduce the risk of transmission?
No, as it does not reduce viral shedding when patient is not on the drug
