STI Flashcards
what is the most common bacterial STI
chlamydia
70-80% of women are asymptomatic, 50% of men are asymptomatic
what are the characteristics of chlamydia bacteria
gram negative obligate intracellular bacterium
stain poorly with gram stains
cell walls lack peptidoglycan
how is chlamydia transmitted
vaginal, oral or anal sex
who is most likely to get chlamydia
20-24 year olds
what percentage of women with chlamydia go on to develop pelvic inflammatory disease
9%
an episode of PID increases the risk of an ectopic pregnancy x10
also carries risk of tubal factor infertility (15-20%)
how does chlamydia present in a female
post coital (after sex) or intermenstrual bleeding
lower abdominal pain
dyspareuria (painful sex)
mucopururlent cervicitis
how does chlamydia present in males
urethral discharge
dysuria
urethritis
epidididymo-orchitis (inflammation of epididymus and testes)
proctitis
what are the complications of chlamydia
Pelvic inflammatory disease Ectopic pregnancy Reactive arthritis (reiter's syndrome) Conjunctivitis Transmission to neonate (conjunctivitis and pneumonia)
what is some testing advice for chlamydia
dont test women >25 with vaginal discharge
do test women who have had CT in past year
what is LGV (lymphogranuloma veneereum)
a server of chlamydia trachoma’s
diagnosed in men who have sex with men
how does LGV present
Rectal pain
Discharge
Bleeding
high risk of concurrent STI
how do you diagnose chlamydia
test 14 days following exposure
Nucleic acid amplification test (NAAT) - females (vulvovaginal swab)
males - urine sample (avoid first urine)
Add a rectal swab id reciprocal anal intercourse
how do you treat chlamydia
doxycycline 100mg 2x daily for 1 week
what is mycoplasma genitalium
emerging sexually transmitted pathogen
associated with non-gonococcal urethritis
prevalence in 1-2% of the population
asymptomatic carriage
need NAAT test to diagnose
what bacteria is Gonorrhoea
gram negative intracellular diplococcus
where does gonorrhoea infect
mucus membranes of the urethra, endocervix, rectum and pharynx
how is gonorrhoea transmitted /incubated
incubation period or urethral infection in men is 2-5 days
20% risk from infected women to male partner
50-90% risk from infected man to female partner
how does gonorrhoea present in males
Asymptomatic <10%
urethral discharge >80%
Dysuria
Pharyngeal/rectal infections (Mostly asymptomatic)
how does gonorrhoea present in females
Asymptomatic (up 50 50%)
Increased/altered vaginal discharge
Dysuria
Pelvic pain
Pharyngeal and rectal infection (asymptomatic)
what are some complications of gonorrhoea
Lower genital tract:
- bartholinitis (glands at either side of vagina)
- tysonitis (Tyson gland infection)
- periurethral abscess
- rectal abscess
- epididymitis
- urethral stricture
upper genital tract:
- endometritis
- PID
- hydrosalpinx
- Infertility
- Ectopic pregnancy
- Prostatitis
how do you diagnose gonorrhoea
NAAT - nucleic acid amplification test (screening test)
microscopy (for symptomatic)
culture (if microscopy +ve or contact of GC)
treatment for gonorrhoea
1st line - Ceftriaxone 500mg IM
2nd line - Cefixime 400mg oil (if IM is contraindicated)
what are the characteristics of genital herpes
first a primary infection
then a non-primary first episode of herpes
then recurrent infection
how long does a first episode of herpes tend to last
14-21 days
incubation 3-6 days
how does herpes present
Blistering and ulceration of external genetalia Pain External dysuria Vaginal or urethral discharge Local lymphadenopathy Fever and myalgia
how do recurrent episodes of herpes tend to present
unilateral, small blisters and ulcers
minimal systemic symtpoms
resolves within 5-7 days
what investigations are done for herpes
swab base of ulcer for HSV PCR
herpes treatment
Oral antiviral treatment (acyclovir 400mg 3x daily for 5-7 days)
if v painful lidocaine 5% ointment can be used
saline bathing
analgesia
what to do if first episode of herpes happens in the 3rd trimester of preganancy
inform O+G to review birth plan
50% risk of transmission to neonate is primary HSV
what is the most common viral STI in the uk
HPV
80% life time risk of getting infection
how many HPV genotypes infect the anogenital epithelium
> 40
what serotypes are associated with different clinical problems
anogenital warts - 6/11
palmar and plantar warts - 1/2
cellular dysplasia - 16/18
what is the incubation period for HPV
3 weeks - 9 months
HPV immunology
spontaneous clearance of wards - 20-24%
clearance with treatment - 60%
persistence despite treatment - 20%
treatment for HPV
Podophyllotoxin (warticon)
- cytotoxic
- not licensed for extra genital warts
Imiquidmod (alder)
- immune modifier
- used on all anogenital warts
Cryotherapy
- cyctolytic
- needs repeat treatments
Electrocautery
what bacteria causes syphilis
treponema pallidum
how is syphylis transmitted
sexual contact
trans-placental/during birth
blood transfusions
non-sexual contact (health care workers)
what are the 2 main classifications of syphilis
congenital
acquired
what are the stages of acquired syphilis
Early infectious:
- primary
- secondary
- early latent
late non-infectious:
- late latent
- tertiary
what is the incubation period for primary syphilis
9-90 days
how does primary syphilis present
Primary chancre (painless ulcer)
lesion appears at site of inoculation
genital (90%)
extra-genital (10%)
non-tender local lymphadenopathy
when does secondary syphilis start
6 weeks to 6 months
how does secondary syphilis present
Rash on palms and soles Lesions of mucous membranes Generalised lymphadenopathy Pathcy alopecia Condylomata lata (v infectious lesions exuding a serum teeming with treponems)
how do you diagnose sylphilis
Dark field microscopy
PCR
from lesions or infected lymph nodes
Serological testing to detect antibodies
what non-treponemal serological tests are done for syphilis
Non-treponemal (look at biomarkers released in cellular damage)
VDRL - venereal disease research lab
RPR -rapid plasma reagin
what treponemal serological tests are done for syphilis
TPPA (treponemal pallidum particle agglutination)
ELISA/EIA - enzyme immunoassay screening test
INNO-LIA - line immunoassay
FTA abs (fluorescent treponemal antibody absorbed)
treatment for early syphilis
2.4 intramuscular Benzathine penicillin x1
treatment for last syphilis
2.4 intramuscular benzathine penicillin x3
what follow up is done for syphilis
syphilis becomes late syphilis when RPR is negative or serofast
titres should decrease fourfold by 3-6 months in early syphilis
which type of genital herpes has higher rates of viral shedding
HSV 2
