Flashcards in Sexually transmitted infections Deck (120):
what is the most common STI in the UK?
what are the different types of chlamydia infections?
serotypes A - C - ocular infections - get into eye fluid and causes conjunctivitis
serotypes D-K - genitourinary infections
L1 to L3 - lymphogranuloma venereum (LGV) - emerging infection in men who have sex with men and can cause proctitis
how is chlamydia infection transmitted?
unprotected vaginal, oral or anal sex
from mother to baby through delivery
what is the pathophysiology of chlamydia infection
C.Trachomatis enters the host cell as an elementary body (infectious form) and then becomes a reticular body, the non-infectious form capable of replication
following replication (by binary fission), the reticular bodies form back into elementary bodies and then cell ruptures to release them.
this cases inflammation and tissue damage.
what type of organism is chlamydia?
Chlamydia Trachomatis is a obligate intracellular gram negative bacteria.
what are the risk factors for chlamydia infection?
sexually active e.g. recent change in partner, no. of partners
partner with chlamydia
co-infection with another STI
non barrier methods of contraception
what is the typical incubation period for chlamydia?
7-21 days (from infection to symptoms
what are the clinical features of chlamydia in women?
majority are asymptomatic - especially in lower genital tract
post coital and intermenstrual bleeding
lower abdominal pain
pelvic inflammatory disease - mild to moderate symptoms
- pelvic tenderness
- mucopurulent endocervical discharge
- cervical excitation
what are clinical features of chlamydia in men?
urethritis - dysuria and urethral discharge
epididymo-orchitis - testicular pain
- epididymal tenderness
- mucopurlent discharge
other than typical genitourinary symptoms of chlamydia what other clinical features are there?
can infect rectum - discomfort and discharge
can infect pharynx - no symptoms
how is chlamydia infection investigated?
women: vulvovaginal swab (first choice), endocervical swab, first pass urine sample
men: first pas urine sample (first choice), urethral swab
use NAAT on specimen
patients are recommended to have a full STI screen, if you have one STI, you are at risk of others and presentation is similar
contact tracing is required.
there is also a national chlamydia screening programme is England for those <25
how is chlamydia managed?
Abx treatment for uncomplicated urogenital chlamydia infection:
- Doxycycline 100mg twice daily 7 days
- OR Azithromycin 1g single dose
if above are contraindicated an alternative is erythromycin or ofloxacin
advice: avoid sexual contact and oral sex until treatment is complete (7 days after Azithromycin)
should we test chlamydia patients for cure after treatment?
not usually required unless suspected poor compliance, symptoms are persistent or pregnant.
if <25yrs, repeat testing is recommended 3 months after treatment
what are the complications of chlamydia in women?
salpingitis and/or endometritis which can lead to PID
PID can lead to perihepatitis (Fitz Hugh Curtis syndrome)
increased risk of ectopic pregnancy
increased risk of infertility
reactive arthritis and reiters syndrome
what are the complications of chlamydia in men?
infection can spread to epididymitis or epididymoorchitis causing testes to become painful and swollen - if left untreated can affect fertility
reactive arthritis and reiters syndrome
What risks does chlamydia in pregnancy have?
increased risk of premature delivery with low birth weight
increased risk of miscarriage and still birth
if child contracts it they will get neonatal chlamydial conjunctivitis (5-12 days after birth) and possibly develop pneumonia (1 to 3 months after birth)
how are pregnant women and neonates treated for chlamydia?
pregnant women - Abx but doxycycline and ofloxacin are contraindicated. therefore use azithromycin/erythromycin
neonates - oral erythromycin
what is the second most common STI in the UK after Chlamydia?
what type of organism causes Gonorrhoea?
gram negative diplococci
how is gonorrhoea transmitted?
oral or vaginal or anal sex that's unprotected
vertical transmission from mother to child
describe the pathogenesis of gonorrhoea?
the bacteria adheres to mucous membranes of uterus, urethra, cervix, fallopian tubes, ovaries, eyes, testes and throat.
it invades the host cell (intracellular)
causes neutrophils to migrate - abscess forms
it has surface proteins that bind receptors on immune cells to inhibit them.
what are the risk factors for gonorrhoea infection?
Men who have sex with men
multiple sexual partners
previous gonorrhoea infection
high density urban areas
what are the clinical features of gonorrhoea in a females?
abnormal vaginal discharge - thin watery yellow/green
lower abdominal pain
signs: mucopurulent endocervical discharge, pelvic tenderness, easily induced cervical bleeding
what is the incubation period for gonorrhoea?
what are the clinical features of gonorrhoea in men?
mucopurulent urethral discharge
signs: discharge and epididymal tenderness
what symptom would you get in gonorrhoea infection of rectum or pharynx?
rectum: discharge, pain/discomfort or asymptomatic
pharynx - asymptomatic
how would you investigate gonorrhoea?
urethral swab/ meatus swab = microscopy and culture
first pass urine - NAAT
endocervical / vaginal swab - NAAT
endocervical / urethral swab - microscopy and culture
NAAT will provide dual testing for gonorrhoea and chlamydia
full STI screen for anyone with symptoms because of symptoms overlapping and same risk factors
how can gonorrhoea be treated?
IM ceftriaxone 500mg and single dose of oral azithromycin 1g
no need to await test results if symptoms are indicative
educate about safe sex
follow up to test for cure
when should you admit a gonorrhoea patient to hospital?
systemic symptoms = malaise, joint pain, fever and rash. this may be indicative of disseminated gonorrhoea infection which could potentially result in meningitis
what are the complications of gonorrhoea?
women: PID, infertility, ectopic pregnancy and chronic pelvic pain
men: spread from urethra to testes and cause epididymo-orchitis which is painful but rarely causes infertility. also Prostatitis
disseminated gonococcal infection - joint pain, rash, meningitis
what are the issues of gonorrhoea infection in pregnancy ?
early fetal membrane rupture
vertical transmission and cause neonatal gonococcal conjunctivitis (eye pain, redness and discharge)
how can gonorrhoea in pregnancy be treated?
same as non-pregnancy
can give neonate prophylactic Abx
what is pelvic inflammatory disease?
infection of the upper genital tract in females which affects uterus, fallopian tubes and ovaries, caused by infective organisms ascending from the lower genital tract
what is the pathophysiology behind PID?
infections such as chlamydia and gonorrhoea (chlamydia being most common) spread from the vagina and cervix to infect the endometrium, fallopian tubes, ovaries and peritoneum causing inflammation.
some microbes Ecoli and bacteriodes do not cause PID but enhance the infection.
other factors that cause it is instrumentation to the cervix e.g. insertion of coil, gynae surgery, termination of pregnancy
in PID what is the typically path of spread of infection?
what are the risk factors for PID?
non barrier contraception
multiple sexual partners
history of STI
low socioeconomic class
what are the clinical features of PID?
can be asymptomatic
lower abdominal pain
post coital bleeding
menstrual abnormalities - IMB, menorrhagia , dysmenorrhoea
abnormal vaginal discharge
more advanced: severe pain, fever , N&V
what is found on vaginal examination of someone with PID?
tenderness of uterus/adnexae or cervical excitation
may be mass in lower abdomen
abnormal vaginal discharge
what are the differentials for PID?
ruptured ovarian cyst
what investigations should be performed for PID?
endocervical swabs - test for gonorrhoea and chlamydia via NAAT
high vaginal swabs - trichomonas vaginalis and bacterial vaginosis
HIV and syphilis screen too
urine dipstick to exclude UTI
transvaginal USS - if severe and uncertain diagnosis
laparoscopy - severe cases and uncertain diagnosis = gold standard because it allows you to observe the inflammatory changes
what is the CDC criteria for PID?
- lower abdominal tenderness
- uterine/adnexal tenderness
- cervical motion tenderness
- temperature >38.3
- abnormal cervical or vaginal mucopurulent discharge
- white blood cells on microscopy of vaginal secretions
- raised ESR/CRP
- lab results of gonorrhoea, chlamydia or trachomatis
- histopathological findings of endometritis on endometrial biopsy
- laparoscopic findings consistent with PID
- transvaginal USS or MRI show thickened filled tubes.
how is PID managed?
14 day course of broad spec Abx before results of swabs
- doxycycline, IM ceftriaxone and oral metronidazole
contact tracing from last 6 months and give them doxycycline
how is PID treated in pregnancy?
Ofloxacin and metronidazole
cant give doxycycline in pregnancy
when should PID be admitted to hospital?
pregnant - risk of ectopic
signs of pelvic peritonitis
unresponsibe to Abx or need of IV
what are the prevention strategies
primary: education, adverts
secondary: screen at risk population
tertiary - treat people to reduce spread and complication
what are the complications of PID?
increases chance of ectopic pregnancy and infertility due to scaring of the fallopian tubes and loss of ciliary function and adhesions
chronic pelvic pain
Fitz Hugh Curtis syndrome
what is Fitz-hugh Curtis syndrome? include symptoms
perihepatitis - spread of PID into peritoneum and then around liver
causes RUQ pain, worse on laughing and coughing
mainly by chlamydia but rare
what is the laparoscopic finding in fitz hugh Curtis syndrome?
Violin string adhesions - due to peritoneum adhering to liver capsule
what type of virus is HIV?
single stranded RNA retrovirus
what is the pathophysiology of HIV?
HIV binds CD4 cells and is uptaken into these cells
the ssRNA genome is then reverse transcribed into DNA by reverse transcriptase
the dsDNA is then inserted into the host cell genome by enzyme integrase.
The host cell then goes onto transcribe and translate as normal but in doing so will produce viral RNA and proteins.
New virus particles can assemble and bud off
the never virus particle matures when the protease cleaves its proteins (after it has left host cell)
the host cell becomes stressed and damaged from this process and thus the virus kills CD4 T cells.
how can the changes in symptoms of HIV be explained? i.e. early on, then later
initially the virus rapidly replicates, killing lots of CD4 cells and thus making the individual feel ill - flu like symptoms.
eventually HIV antibodies are made and viral replication is kept low and number of CD4 cells remains stable - latent phase - asymptomatic
years later eventually immune system cant keep up and CD4 cells slowly reduce and without treatment it will lead to AIDS
how is HIV transmitted?
sharing of injecting equipment
blood products, organ donation, artificial insemination
vertical - utero, birth, breastfeeding
more likely to catch it if viral load is higher (i.e. someone who is not being treated), already have an STI or breaks in skin
which groups of people are at risk?
men who have sex with men
IV drug users
high prevalence areas
having sex with a partner who has lived or recently travelled to Africa
what are the clinical features of the initial seroconversion illness?
How does HIV present after latency?
frequent infections - candida/ HSV
name 4 AIDS defining illness's
Pneumocystis jiroveci pneumonia
what investigations are carried out to diagnose HIV?
fourth generation test - first line
- ELISA - test for serum HIV Ab and p24 antigen
- Reliable after 4-6 weeks
how is HIV managed?
Highly active anti-retroviral therapy (HAART)
- includes nucleoside reverse transcriptase inhibitors (NRTIs), protease inhibitors and non-nucleoside reverse transcriptase inhibitors and integrase strand transfer inhibitors. All reduce viral replication and maturation
- e.g. Stribild or Atripla - each contain a combination of the different drugs
how effective is HAART?
- does not cure but reduced viral load to undetectable levels making prognosis excellent.
- life long treatment so compliance is key
what drugs can HIV medications interact with?
how is HIV monitored?
HIV viral load
FBC, U&Es, urinalysis, LFTs
what is post exposure prophylaxis for HIV?
can be given up to 72 hours after exposure to lower risk of becoming infected.
PEP consists of 1 month of:
- Truvada (once a day)
- Raltegravir (twice a day)
what measures are taken to reduce HIV vertical transmission?
avoid breast feeding
antenatal anti-retroviral therapy during pregnancy and delivery
neonatal post exposure prophylaxis
what type of organism causes syphilis infection?
spirochete gram negative bacterium
how does Treponema pallidum transmit?
motile bacterium enters through a break in skin or intact mucous membranes OR mother to fetus via the placenta and through infected blood products
describe the pathogenesis/ life cycle of treponema pallidum...
once contaminated new host the bacteria divides and forms a papule which ulcerates into infectious hard ulcers (chancre) form at the site of contact after an incubation period of 2-3 weeks
the first stage is acquired symptomatic syphilis = primary syphilis
If left untreated this develops into secondary syphilis where there is more systemic symptoms like malaise, rash etc
Next the latent phase occurs where the individual is asymptomatic
finally tertiary syphilis follows involving multiple organs including heart and nervous system - causes damage via obliterating arteritis which leads to endothelial cells proliferating and occluding the lumen of vessels and thus resulting in ischaemia
what are the risk factors for syphilis infection?
engaging in unprotected sex - especially with high risk partners
multiple sexual partners
how can the clinical features of syphilis be categorised?
can be categorised into congenital and acquired
symptomatic (primary, secondary, tertiary) and asymptomatic (latent)
what are the clinical features of primary syphilis ?
papules that ulcerate into hard chancres
chancres are painless, non itchy and typically develop 9-90days post infection on genital sites (penis, scrotum, anus, cervix, labia)
chancre are usually singular
chancre usually heal within 3-10 weeks with/without symptoms
what are the clinical features of secondary syphilis ?
skin rash - hand and soles of feet - not itchy or painful
malaise, fever, arthralgia, weight loss, headaches
silvery-grey mucous membranes -oral, pharyngeal, genital
Condylomata lata - elevated papules like warts at moist areas of skin e.g. axilla, anogenital
many other manifests can infect kidneys liver and brain
if syphilis is left untreated what proportion will self heal?
what are tertiary features of syphilis?
what is gummatous syphilis ?
form of tertiary syphilis
granulomas form in bone, skin, mucous membranes of the upper respiratory tract, mouth and viscera or connective tissue.
which stages of syphilis is a patient not infective?
latent and tertiary
i.e. gummatous syphilis is not infectious
describe features of neurosyphilis.
Tabes dorsalis: degeneration of neural tracts predominately dorsal columns.
Dementia - cognitive impairment, mood alterations, psychosis
meningovascular complications - cranial nerve palsies, stroke, cerebral gummas
Argyll Robertson pupil: pupil constricted and unreactive to light but reacts to accommodation
what are the symptoms of Tabes dorsalis?
loss of pain and temperature sensation
what are the cardiovascular complications of syphilis?
aortic regurgitation due to aortic valvulitis
aortic root dilation
angina due to stenosis of coronary ostia
dilation and calcification of ascending aorta
what investigations can be done to identify syphilis?
dark ground microscopy of chancre fluid - detects spirochaete in primary syphilis = looks like stars in a night sky and constantly moving
PCR testing of swabs from active lesions
lumbar puncture - CSF ab tests in neurosyphilis
what different serological tests are available for syphilis?
Treponemal ELISA (IgG/M) - positive for life
TPPA (enzyme immune assay) or TPHA - positive for life
Rapid plasma regain (RPR) test / VDRL - rises in early disease, falling titres indicate progression to late disease (RPR test is similar to CRP but for syphilis)
since Ab are present for life even after cure, the best way to test cure is via RPR test and only way to test reinfection is RPR being raised.
How can syphilis be managed?
Penicillin is the treatment of choice
need long course because of slow replication of treponema pallidum
early syphilis: benzathine penicillin IM single dose
late syphilis: benzathine penicillin IM 3 doses at weekly intervals
neurosyphilis = procaine penicillin + probenecid 14 days OR benzylpenicillin every 4 hours daily for 14 days
other: avoid sexual contact, screen for other STIs, contact tracing. follow up serology to check response.
what could be done in syphilis patients with penicillin allergy?
desensitisation to penicillin should be considered
what is the Jarisch Herxheimer reaction?
inflammatory response secondary to death of treponemas
flu like illness within 24 hours of treatment
treat this with supportive measures unless cardio or neurosyphilis then give oral steroids prior to Abx to reduce acute localised inflammation
can syphilis affect pregnancy?
T. pallidum has the potential to cross the placenta or infect the baby during delivery
pregnant women need to be treated early otherwise can lead to miscarriage , still birth, preterm labour or congenital syphilis.
what are the features of congenital syphilis?
saddle nose, rash, fever, failure to gain weight
what type of organism causes gential warts?
HPV - DNA virus
HPV 11 and 6 cause the majority of angogenital warts
describe the pathogenesis of HPV
replicates in keratinocytes and causes mucosal outgrowths
spread by skin to skin contact during vaginal and anal intercourse
can be passed vertically to baby during delivery but rare
what are the risk factors for genital warts?
early age at first intercourse
multiple sexual partners
how does HPV present?
warts can develop weeks, months to years after initial infection
state 2 differentials for genital warts:
Molluscum contagiosum - viral
Vestibular papillomatosis - projections of vestibular epithelium or labia minora (non viral)
how can vestibular papillomatosis be differentiated from HPV?
Vestibular papilomatosis does not turn white under acetic acid. HPV does
how is HPV investigated?
genitalia examination - can magnify small lesions
speculum/colposcopy +/- acetic acid to identify cervical lesions
how is HPV infection managed?
lesions are most likely to spontaneously resolve overtime.
- excision under local anaesthetic
- cryptotherapy - freezing with liquid nitrogen
- laser surgery
state 2 types of topical treatment for warts, how they differ in dose and what type of warts they are suited for..
- Imiquimod = apply 3x weekly and then wash off after 6 to 10 hours (up to 16 weeks) - good for large warts
- Podophyllotoxin = applied 2 times a day for 3 days and then 4 days rest (4 to 5 cycles) - good for small clusters
Does HPV/warts cause problems in pregnancy?
NOT associated with miscarriage, preterm etc
however due to immunosuppression the warts can multiple/grow larger
in very rare case, child can develop respiratory papillomatosis - genital warts in throat.
how does treatment of warts in pregnancy differ from non-pregnancy?
topical treatments cannot be used
so ablation used instead
what is the pathophysiology behind herpes infection?
HSV1 and 2 are responsible for infection of mucosal areas around mouth and genitals.
HSV enters body through small cracks in the skin and mucous membranes
it then travels to the nearest nerve to reach the ganglion where it remains.
the virus can stay dormant and then reactivate at a later date.
there are 4 stages of infection:
- vesicle and feeling unwell
- crusted lesion
what is the incubation for HSV?
incubation of about 3 to 14 days
what is autoinoculation?
HSV can be transferred to different regions of the body of the same individual
what are the risk factors for HSV infection?
multiple sexual partners
oral sex with someone with coldsores
Describe the clinical features of the primary HSV infection on genitals...
small red blisters around genitals that are very painful and can form open sores. In women found on vulva, clitoris, buttocks and anus. in men found on penis, anus, buttocks and thigh.
dysuria - acid irritates sores - not quite same symptoms as a UTI so ask this in history to distinguish
vaginal / penile discharge
flu-like symptoms - fever, malaise, muscles (systemic symptoms are only in primary attacks)
after around 20 days, lesions crust and heal
Describe the clinical features of secondary infection i.e. recurrent infection?
shorter and less severe attacks compared to primary
this is because Ab production is quicker due to recognition
still get burning and itchy and red painful blisters
what are cold sores?
HSV infection around the mouth
painful lesions around the mouth and nose that lasts between 7-10days
mainly caused by HSV1 but overlap
what investigations are recommended in someone presenting with genital herpes?
history - no. of partners, partners with cold sores
examination - vulva are swollen and can see sores
swabs from open sores - PCR to test for viral genomes
rule out UTI and thrush
can Ab testing be used to diagnose for HSV?
50% of people have HSV so Ab are not useful
only useful in pregnancy to see if mother has Ab to give to baby
how is HSV managed for primary infection?
- aciclovir - reduces no. and size of lesions
- educate about preventing transmission to others
- Full STI screen
- avoid sexual contact during outbreak
- advice - wee in salt water to prevent urine touching sores. OR use lidocaine cream before weeing. advice to prevent autoinoculation
how does management of recurrent HSV infections differ?
usually just with analgesia and icepacks
if outbreaks are regular then episodic aciclovir treatment can be used - use aciclovir ASAP to reduce time and severity of outbreak
if outbreaks become very frequent (>6/yr) then suppressive treatment is recommended - daily doses of aciclovir
what are the complications of genital herpes?
vulval adhesions can occur - use Vaseline to prevent this
urinary retention - too much pain from weeing
psychological - reassure them that it doesn't mean partner is sleeping around, could be from a coldsore
how is herpes infection managed in pregnant women?
depends if it Is a primary or recurrent attack.
recurrent attacks are no problem because Ab has already been passed to baby through placenta (can double check by Ab testing mother). So no treatment is required, however for anxious mothers to supress likelihood of recurrent attack during time of childbirth, prophylactic aciclovir in T3 can be given. However C section is not recommended because no risk to baby
if mother contracts herpes during last trimester of pregnancy, there is no time to transfer Ab to baby and thus C section is recommended to prevent transmission in childbirth
what are the forms of neonatal herpes?
skin, eyes and mouth (SEM herpes)
Disseminated herpes - effects internal organs
CNS herpes - can lead to encephalitis
how is neonatal herpes managed?
antiviral therapy is usually enough for SEM herpes but mortality is much higher for disseminated and CNS herpes
what organism causes Trichomoniasis ?
Protozoan Trichomonas Vaginalis
anaerobic flagellated protozoan
describe the pathogenesis of trichomoniasis ?
transmitted through unprotected vaginal sexual intercourse (not oral/anal)
can infect female urethra, vagina and paraurethral glands and male urethra and under the foreskin
can be transmitted to baby via delivery but RARE
replicates by binary fision, destroying epithelial cells and releasing cytotoxins
what is the link between HIV and trichomoniasis?
thought that Trichomoniasis infection increases risk of contracting HIV.
what are the risk factors for Trichomoniasis infection?
multiple sexual partners
history of STIs
older women are more at risk of being infected
what are the clinical features of Trichomoniasis?
many infections are asymptomatic
if symptoms do develop it takes around 28 days after infection.
- offensive vaginal odour
- abnormal vaginal discharge - thick/thin/frothy and yellow/green
- itchiness or soreness of the vulva
- urethral discharge, dysuria, urinary frequency, pain and itching around foreskin.
what is the sign 'A strawberry cerix' and when is it seen?what other signs are associated with this condition?
strawberry cervix - punctate and papilliform appearance of cervix in women with Trichomoniasis infection
other signs of trichomoniasis:
- urethral discharge
- balanoposthitis (inflammation of glans)
what investigations should be performed to diagnose trichomoniasis?
females - high vaginal swab taken from posterior fornix
males - urethral swab or first void urine sample.
if positive contract tracing and full STI screen
how is trichomoniasis infection managed?
can the same medication be used in pregnancy?
Metronidazole 2g in one single dose OR 500mg twice daily for 5-7 days
metronidazole can be used in pregnancy but not high doses
are there risks of Trichomoniasis infection in pregnancy?
low birth weigh
risk of post partum sepsis