Sexually transmitted diseases Flashcards
Describe how common sexually transmitted
diseases present, their long term consequences
and how awareness has reduced the STD burden
in the developed world
LOs: How well do you know these?
Why are STDs difficult to control?
Increasing density/mobility in populations, difficulty in changing human behaviour, absence of vaccines for all apart from HPV
What is the urogenital tract?
the organs of the reproductive system and the urinary system.
Why can microorganisms spread easilhy from on easpect of the urogenital tract to another?
It is continuous, so microorganisms can spread easily from one part to another
How is lactic acid produced in the vagina to inhibit colonisation
Glycogen produced as a by-product causes lactobacilli to colonise, producing lactic acid
How does syphilis enter the body?
Via (treponema pallidum) minute abrasions skin/mucous membranes (does not survive outside body well, sensitive to drying, heat, and disinfectants). Can also be transmitted vertically
What are the stages of syphilis
(initial contact) primary, secondary, latent, tertiary
When is primary syphilis and what are its signs
2-10 weeks after infection. Observe enlarged inguinal nodes, spontaneous healing
When is secondary syphilis observed and what are the signs
1-3 months after primary syphilis, shows flu-like illness, with illness, myalgia, headache, fever, MSK rash and spontaneous resolution
This is beacuse of multiplications and lesion production in lymph nodes, liver joints, muscles, skin, mucous membranes
How long is syphilis latent for?
3-30 years, as treponemas dormant in liver/spleen
What can happen with tertiary syphilis?
Neurosyphilis, cardiovascular syphilis, aortic lesions, heart failure.
Sparked by dissemination and invasion, host respinse
What is neurosyphilis
Neurosyphilis refers to infection of the central nervous system in a patient with syphilis and can occur at any stage.
What are the 3 ways that vertical transmission of T Pallidum can affect a baby
Serious infection causing intrauterine death,
Congenital abnormalities which may be obvious at birth
Silent infection which may not be apparent until about 2 years age (facial deformity)
WHy are non-specific tests called non-specific?
The produce a non-specific antibody that reacts to cardiolipin
What are the two non-specific tests?
Venereal disease research laboratory test (VDRL) or rpaid plasma reagin (RPR)
What specific tests can be used to identify T Pallidum
Enzyme linked immunosorbent assay (ELISA) detects IgM and IgG,
Fluorescent treponemal antibody absorption (FTA-ABS) finds reaction woth antigens,
Microhaemagglutination assay for T pallidum
WHat is the main useful drug in treating syphillis/T Palladum
Penicillin
How can secondary and tertiary disease be effectively prevented
Early diagnosis and adequate treatment, including contact screening (patients with other STIs should be screened)
WHat organism causes gonorrhoea
The gram negative coccus “Neisseria gonorrhoeae”
How does gonorrhoea present within 2-7 days
In male there is urethral discharge and pain passing urine (dysuria)
In females is vaginal discharge
How does gonorrhoea affect the GU system?
Pelvic inflammatory disease (PID), Chronic pelvic pain, or infertility due to damage to fallopian tubes
What tests are done to identify gonorrhoea
Microscopy and culture, molecular tests
Does Chlamydia invade host cells
Yes, but it is caused by a bacterium, not a virus
What organism causes chlamydia
Chlamydia trachomatis serotypes D-K cause sexually transmitted genital infections
How can chlamydia effect males
Urethritis, epididymitis (tube at back of testes) proctitis (inflammation of inner rectal lining) and conjunctivitis
Systemic spread, reiters syndrome
How can women be affected by chlamydia
Urethritis, cervicitis, Bartholinitis (inflammation of bartholin glands by vagina) salpingitis (fallopian tubes) and conjunctivitis, Also can cause etopic pregancy (egg implants outside womb) infertility, perihepatitis, arthritis dermatitis
How can neonates be affected by chlamydia
Conjuntivitis, pneumonia
Wow does chlamydia enter the body?
Chlamydiae enter the host through minute abrasions in the mucosal surface
How is chlamydial infection treated?
with doxycycline or azithromycin
What 2 viruses are most common
HSV 1 and HSV 2
How does genital herpes present
Ulcerating vesicles that take up to 2 weeks to heal
How do recurrent cold sores form
the virus in the lesion travels up sensory nerve endings to establish latent infection in dorsal root ganglion neurones. From this site it can reactivate, travel down nerves to the same area, and cause recurrent lesions (‘genital cold sores’).
Aseptic meningitis/encephalitis are rare complications
How is genital herpes diagnosed?
Clinical apperance, but HSV DNA can be detected and typed in vesicle fluid/ulcer swabs
WHat is genital herpes treated with
Aciclovir
What types of HPV are linked to genital warts
11 and 16
What types of HPV are linked to cervical cancer
16 and 18
What is the major route of HIV transmission in undeveloped countries
Heterosexual and vertical transmission
What is the major route of HIV transmission in developed countries
Homosexual
