STD Flashcards
what are examples of STIs caused by bacteria? (3)
- syphilis- Treponema pallidum
- gonorrhea- Neisseria gonorrhea
- non-gonoccal urethritis: chlamydia trachomatis
what are examples of STIs caused by viruses
herpes simplex virus 1 and 2
human papilloma virus (HPV)
viral hepatitis
AIDS/HIV
examples of STIs caused by fungi (1)
vaginal candidiasis- candida albicans
examples of STIs caused by parasites
- scabies
- pubic lice
what are the modes of transmission of gonorrhea?
- mainly by sexual intercourse with infected person
- direct contact of broken skin with open sores, blood or genital discharge
- by receiving contaminated blood
- from infected mother to child during pregnancy (MO crosses placenta) or childbirth (pass through bith canal)
what are the risk factors for STI? (5)-
- unprotected sexual intercourse
- number of sexual partners
- MSM (men who have sex with men)
- prostitution
- illicit drug use- shared needles, contaminated blood
what are indv prevention methods for STI? (5)
- abstinence and reduction of number of sexual partners
- barrier contraceptive methods (prevent exposure of MO of sti)- eg. male condoms
- avoid drug abuse and sharing needles
- pre-exposure vaccination (eg. HPV, hepB)
- post exposure prophylaxis eg. HIV
why is management and prevention of STDs impt?
- to reduce related morbidity, and progression to complicated disease
- to prevent HIV infection
- prevent serious complications in women
- protect babies
whcih bacteria causes gonorrhea?
- Neisseria gonorrhoeae (intracellular gram neg diplococci)
how is gonorrhea diagnosed?
- gram stain of genital dischrage
- culture
- PCR- to identify nucleus mateiral
what are the sx of uncomplicated gonorrhea? male and female?
male
- purulent urethral discharge, dysuria, urinary freq
females
- mucopurulent vaginal dishcarge, dysuria, urinary freq
what are soem complications for untreated gonorrhea? male and female
male
- epididymis, prostatitis, urethral stricture, disseminated disease
female
- pelvic infalm disease, extopic pregnancy, infertility, disseminated disease (enter into bloodstream)
hwo to manage uncomplicated urogenital gonorrhea infection?
dual ab therapy
what are teh advatnages of dual ab therapy for gonorrhea
- imrpoves tx efficacy
- slows emergence of resistance
- treat chlamydia trachomatis- usually co-infect with uncomplicated gonorrhea
what is the dual ab therapy for gonorrhea
- IM ceftrixone 250mg single dose + PO azithromycin 1g single dose concurrently
if allergic to azi:
- IM ceftrixone 250mg single dose + doxycycline 100mg BID x 7 days
if allergic to penicillin
- IM gentamicin 240mg single dose or + POazi 2g
- IM spectinomycin 2g single dose + PO axi 2g
wat are the advatnage of azithromycin? (2)
- single dose, improve compliance
- higher prevalence of gonococcal resistnace to tetracycline than azi
what is chlamydial infection caused by?
chlamydia trachomatis bacteria
how is chlamydial infection diagnosed?
NAAT (PCR) or antigen detection
how is chlamydial infection transmitted
sexual contact
mother to child during childbirth
what is the rec regimen to treat chlamydial infection ?
azithromycin 1g pO single dose
or doxycycline100mg PO BD x 7days
tx highly effective, testing not req unless specific conditions or sx arise
what is syphilis caused by?
treponema pallidum bacteria
how is syphilis transmitted?
sexual transmission only when mucocutaneous syphilic lesions are present
non-sexua
- transplacental from other to child
- contaminated blood
how is syphillis diagnosed?
- darkfield microscopic exam of serous material from suspected lesions- confirmatory, good for early stage
- serology - nontreponemal test: use nontreponemal antigen to detect treponemal ab, +VE test indicates presence of any stage of syphilis==> results reported in quantitative VDRL/RPR test
- : less specific, screening tool. if pos, then do treponemal test
- serology- treponemal test: to detect treponemal ab
+: more sensitive and specific than nontreponemal tests, used as confirmatory tests
may remain reactive for life, hence not for monitoring response to tx
what is the ab regimen for pri/sec/early latent (<1 year) syphilis?
-IM benzathin penicillin G 2.4 mil units x 1 dose (slow drug release)
if penicillin allergic
- PO doxycycline 100mg BD x 14 days
what are the counselling pointers for doxycycline?
- take with food to reduce GI upset
- remain upright
- take with glass of water
what is the ab regimen for late latent (>1 year) or unknown duration syphilis?
- IM benzathine penicillin G 2.4mil once a week x 3 dose
if penicillin allergic
- PO doxycycline 100mg BD x 28 days
what is the ab regimen for neurosyphilis?
IV crystalline penicillin G 3-4mil units q4h x 10-14 days
OR
IM procaine penicillin G 2.4MU daily + PO probenecid 500mg QID x 10-14 days
if penicillin allergy
- IV/IM ceftriaxone 2g daily x 10-14 days
if concern for cross sen, skin test to confirm penicillin allergy, desensitive if necessary
how to monitor therapeutic response for syphilis?
- jarisch - herxheimer rxn (acute febrile rxn with headache, myalgia)- usually occur within first 24h of tx
tx success= decrease in VDRL or RPR titre by at least four fold- take at 6 and 12 months
what is considered tx failure for syphillis
at 6 months
- show s/sx of disease
- failure to decrease VDRL or RPR titre by fourfold
- retreat and re-eval for unrecognised neurosyphilis
properties of herpesvirus? (4)
- double stranded DNA virus
- replicate in host cell nucleus
- persist indefinitely (lifelong) in infected host
- periodic reactivation, esp in immunosup hosts
what is HSV type 1
- mostly in young children
- transmission via contact
- forms: cold sore
- usually self limiting
- may be reactivated by stimuli eg. fever, menstruation, sunlight, stress
- reactivation may be clinically asx or be a life threatening disease
NOT AN STI
what is HSV type 2
- young adults
- sexual transmission
- genital herpes
- may be reactivated by stimuli eg. fever, menstruation, sunlight, stress
- reactivation may be clinically asx or be a life threatening disease
- usually self limiting
STI
what is varicella zoster virus?
- causes 2 distinct forms of disease: varicella (chickenpox) and herpes zoster (shingles)
pri infection: chickenpox, results in diffuse vesicualr rash
reactivation: localised skin infection, shingles
NOT AN STI
what is the antiviral tx for varicella/shingles?
- Acyclovir PO 800mg 5 times daily x 7 days
- valacyclovir PO 1g TDS x 7days
start within 24-48h of rash to reduce duration and severity of sx
what is the cycle of HSV infection (5 stages)
- primary mucocutaneous infection
- infection of nerve ganglia
- establishment of latency
- reactivation
- recurrent outbreaks/flairs
how is genital herpes transmitted?
- transfer of body fluids
- intimate skin-to skin contact
what is the incubation period of genital herpes
2-14 days (mean 4 days)
how is genital herpes diagnosed?
what are the clinical presentation of herpes?
pt history: previous lesion/ sexual contact with similar lesions
presntation/sx
- classical painful multiple vesicular or ulcerative lesions
- local itching, pain , tender inguinal adenopathy
- flu like sx (eg. fever, headache, malaise)
- prodromal sx eg. mild burning, itching
*sx less severe in recurrent disease ( less lesions, heal faster, milder sx)- alr built up some form of immunity against virus
what virologic test can be done to diagnose genital herpes?
- viral cell culture
- PCR for HSV DNA
what serologic tests can be done to diagnose genital herpes?
- ab to HSV dev durign first several weeks after infection and persist indefinitely
- not useful for first ep, takes 6-8 weeks of serological det following first ep
what is the managmenet goal of genital herpes
- relieve sx
- shorten clinical course
- prevent complications and recurrence
- decrease transmission
what supportive care can be given for genital herpes
- warm saline bath to relieve discomfort
- good genital hygiene to prevent superinfection
- counseling on natural history
what antiviral is given for first ep (herpes type 2)?
- acyclovir PO 400mg TDS for 7-10 days
- acyclovir IV 5-10mg/kg q8h x 2-7 days, complete with PO for total 10 days
- valacyclovir PO 1g BID 7-10days
MOA of acyclovir?
inhibit viral DNA polymerase–> inhibit DNA synthesis and rep
F: 10-20%, therefore need freq dosing
F of valacyclovir: 55%- can reduce freq and increase dose
what is recurrent genital herpes?
- almost all person with sx will experience recurrent flares
- pt hv a median of 4 recurrences in the year after first sx episode
how to manage recurrent genital herpes?
- antiviral as chronic suppressive therapy
- episodic therapy
choice based on pt preference
advantages of chronic sup therapy? (4)
- reduce freq of recurrence by 70-80% in pt who have freq recurrences (>6/year)
- no sx outbreaks
- improved quality of life
- established long term safety and efficacy
- decreased risk of transmission (in combi with consistent condom use and abstinence)– reduces virus shedding
cons of chronic sup therapy (4)
- cost
- compliance
- ADR
- recurrence occurs at baseline freq with discont
what is the rec regimen for chronic sup therapy (3)
- acyclovir 400mg PO BDS
- valacyclovir 500mg PO OD (may be less effective for pt with freq rec)
- valacyclovir 1g PO OD- give if pt has >10 ep/year
duration is pt and disease course dependent
pros of episodic therapy? (3)
- shorten duration and severity of sx
- less costly
- more likely to be compliant
cons of episodic therapy (2)
- req initiation of therapy within 1 day of lesion onset
- does not reduce risk of transmission (will not lower asx viral shedding)
what is the rec regimen for episodic therapy
- acyclovir 400mg TDS x 5 days
- acyclovir 800mg BDS x 5 days
- acyclovir 800mg TDS x 2 days
- valacyclovir 500mg BDS x 3 days
- valacyclovir 1g OD x 5 days
how to counsel person with HSV infection
- educate concerning natural history of disease
- encourage to inform current and future sex partner
- sexual trans can occur during asx period
- shoudl remain abstinent from sexual activity with uninfected partner when lesions present
- risk fo HSV sexual trans can be reduced with daily use of valacyclovir or acyclovir
- risk for neonatal hsv infection
- increased risk of hiv acquisition
how is sex partner managed? (of infected HSV pt)
- symptomatic partner should be evaluated and treated if hv
- asx- questioned concerning history of genital lesion, offered type specific serologic testing for hsv infection
