W11 L3 Fri STI Flashcards
What is STI
- Sexually Transmitted/Transmissible Infections
- Spread primarily through person-to-person
sexual contact (horizontal).
– Some can also be transmitted from mother to child (ie vertically)
– blood products and tissue transfer (blood borne viruses BBV)
Classification of STI
-Bacteria (chlamydia, gonorrhea, syphilis)
-Viral (all name start with H)
-Parasitic (trichonomas, pubic lice, scabies)
HIV history
- 1884 - 1924 SIV transfere to humans as HIV
HIV 1: chimpanzee origin from cameroon, Congo (high virulence)
HIV2 sooty mangabe from monkey, less virulent
Epidemology of HIV
-Up to 39 million people world wide
-1.3 million newly acquired per year
-630000 people die per year
-there has been a decline in number of people acquiring HIV and HIV related death globally over time
HIV epidemiology in AUD
- HIV in Australia (end of 2021)
– 27,390 people living with HIV
– HIV notifications coming down
– 68% new notifications are amongst Men who have sex with men - 27% Heterosexuals
- <2% Injecting drug use
HIV infection method
-unprotected sexual intercourse with an infected partner
-vertical transmission ( utero, delivery or breast milk)
-injection drug use ( shared needle, blood transmissions)
Pathophysiology of HIV
`-Virus bind to CD4 receptor
-binding to coreceptor CCR5 or CXC4
-the virus fuse and release it’s viral load
-the viral RNA is reverse transcript and integrated into the genome
-cell produce viral mRNA, translation and make new virus
Management of HIV
- in the past, need to take anti-viral tablet at precise time
-now, only one pill per day (combinational drug), allow them to have a normal live
-long acting treatment, injection once every 2 month(6 month injection might be available)
What is pelvic inflammatory disease
-Spectrum of inflammatory disorders of the upper female genital tract
* Polymicrobial infection
* Sexually transmitted pathogens more likely in younger, sexually active women
common organisms that can cause pelvic inflammatory disease
– Chlamydia (50%)
* ~10% of chlamydial cervical infection ascend to cause PID
– Gonorrhea (25%)
* Overseas contact, remote Aboriginal communities
– Mycoplasma genitalium (?%)
– Bacterial vaginosis (?%)
Epidemiology of Chlamydia and gonorrhea notifications (VIC)
-increase in infection per year, only slowed down a bit due to covid but infection rate has increasing since then
epidemiology of PID
- ‘silent epidemic’
- ~10,000 Australian women treated for PID in
hospital each year
– Aged 20-29 years have highest incidence
Pathophysiology of PID
-STD bacteria enter vagina with semen
-bacteria pass through cervix, into uterus. finally into ovarian tubes and ovary. become infected
-from there, it can spread to other region of the body
Clinical manifestations of PID
- Range from no symptoms to severe
– Lower abdominal pain
– Menstrual disturbances
– Vaginal discharge
– Deep pain during sex
– Fever
consequences of PID
– Tubal infertility (1 in 8)
– Chronic pelvic pain
– Ectopic pregnancy
due to inflamed and scarring of ovary and fallopian tube
Management of PID
- Triple antibiotics
– BUT is it too late??
– (doesn’t reverse damage) - Reduce chlamydia, gonorrhea incidence
– Consistent condom use
– Monogamy
Herpes Simplex Virus epidemiology
- Genital herpes caused by HSV 2
– But rising numbers of HSV1 cause over recent years - > 50% initial genital episodes now caused by HSV 1
- Most (2/3rd ) HSV infections are asymptomatic
– ~80% unaware - Seroprevalence
– HSV 1 – 20-80%
– HSV 2 – 12% - 80% FSW, 60% MSM, 50% STD clinic attendees
Pathophysiology of herpes
- Double stranded DNA virus
- Phases of herpes infection
– Primary infection (flue like illness)
– Latency * Nerve cell ganglia
– Re-activation
Clinical manifestations of herpes
- First episode
– Flu like symptoms
– Genital ulcers
– Swelling/pain genital area
– More subtle features( Erythema with tingling/itching, Fissures) - Recurrences
– Less painful, shorter duration than first episode
Why is herpes consider bad
- Psychosexual morbidity
- Enhanced HIV transmission
- Eye disease (corneal ulceration, keratitis, acute retinal necrosis)
- Neurological (meningitis)
- Neonatal herpes
Neonatal herpes
- Rare but serious
- Disseminated infection – Untreated 90% mortality
- “Localized” – skin, eyes, mouth (SEM)
- CNS infection
Management of herpes
- No cure but manageable
– Analgesia
– Antivirals (Episodic, Suppressive)
– Psychosexual counseling
Epidemiology of syphillis
- Overall prevalence ~20 million (2016)
- 6.3 million incident cases annually worldwide
– Mainly heterosexual adults
– BUT congenital syphilis continues to be a major issue - In high income countries, MSM are primary risk group (with about half coinfected with HIV)
increase regconisation in low income countries too
Transmission of syphillis
– Most through sexual contact
* Vaginal, anogenital, orogenital
– Congenital
* In utero, (birth canal)
Pathophysiology of syphillis
- Penetrates intact mucous membranes or dermal microabrasions
- Enter lymphatics and blood to spread throughout body
- Attaches to endothelial lining of blood vessels causing inflammation (endarteritis,periarteritis)
– Later, hypersensitivity response to organism causing gummatous lesions and necrosis
Clinical features of syphillis
- Primary ulcer (chancre) – Appears 9-90 days after direct contact
- Secondary stage
– 6 weeks to 6 months after infection
– Maculopapular rash in 50-70%, may affect palms and soles
Tertiary stage
Most common presentation (~15%) = gummas - Deep seated destructive nodules in bone, skin, other organs
- Cardiovascular invt -> damage to aortic valve and ascending aorta
Human papillomavirus epidermology
- Most prevalent STI in the world – “common cold”
- Lifetime prevalence >50% in sexually active
Pathophysiology of Human papillomavirus epidermology
- Double stranded DNA virus
- > 100 types
- 40 that affect genital region
– Oncogenic
– Non-oncogenic - Most cleared spontaneously depending on HPV type and host immunity
HPV associated cancer
– Cervical
– Oropharyngeal
– Vaginal/Vulval
– Penile
– Anal
MAnagement for HPV
- Warts
– Local destructive therapies - Cryotherapy
- Creams (Imiquimod, Podophyllin)
