Sexually Transmitted Diseases Flashcards
What are the most common presentations of an STD?
urethritis
cervicitis
vaginitis/vaginosis
genital ulcers
What are the three main causes of urethritis?
N. gonorrhoeae
C. trachomatis
M. hominis
What are the two main causes of cervicitis?
C. trachomatis (D-K)
M. genitalium
What are the two main causes of vaginitis?
T. vaginalis
C. albicans
What are the two main causes of Vaginosis?
Gardnerella spp.
Mobiluncus spp.
What bug causes syphilis?
Treponema pallidum
Which is the main HSV that causes genital infections?
HSV-2
but also some HSV-1
What bug causes chancroids/
H. ducreyi
What bug causes lymphogranuloma venerum?
C. trachomatis (subclass L)
What causes genital warts?
HPV
What are the SYSTEMIC STIs?
HIV-1 and HIV-2
Pelvic inflammatory disease from N. gonorrheoa, C. trachomatis or anerobes
What are the two STIs that lead to cancer?
HPV - cervical carcinoma
KSHV - Kaposi sarcoma
What is the main way to break down the organisms causeing genital ulcers?
is it painful?
painless - syphilis
painful - HSV
What do the cells that suggest HPV infection look like/
large atypical cells with lots of cytoplasm. can be binucleated - koilocytes
What are the two main wart diseases?
HPV and Molluscum contagiosum
How do we identify the different strains of HPV?
PCR
Describe the morphology of HPV.
dsDNA
circular genome
icosahedral
nonenveloped
in the papilomavirus family
True or false - the HPV virus goes systemic eventually.
false - it’s usually only local
In the first host cell for infection, what is necessary for the HPV to take off?
The host cell has to be replicating so that the virus can go along for the ride and replicate it’s genome. Then once viral replication progresses, certain strains can produce oncogenes which leads to uncontrolled growth that makes its way up to the surface
What urethritis bug is most likely to have purulent discharge?
gonorrhea
chlamydia, mycoplasma hominis and ureaplasma typically have clear discharge
Describe the morphology of gonorrhea
gram negative diplococci
they are NOT obligate intracellular, but you do typically find them in neutrophils or epithelial cells during infection
Is gonorrhea oxidase positive or negative?
positive
What fuel does neisseria gonorrhea use?
ONLY glucose
N. meningitidis does both maltose and glucose
What is the main virulence factor for neisseria?
specialized pili that allows for attachment to mucosal surface
antigenic variation of this can evade host defences and prevents killing by phagocytosis
What other virulence factors does neisseria have?
endotoxin
IgA protease
note - this neisseria gonorrhea has no capsule, but neisseria meningitidis does
What media do you grow Neisseria on?
Thayer-Martin Media
Why Thayer-Martin?
It’s’ highly specific
inhibits the growth of almost everything else wtih vancomycin, colistin, nystatin and SXT to kill most other gram + and _ along with fungi
nutrients include chocolate sheep’s blood, beef influsion, casein hydroxylase and starch
What is the general treatment for STD neisseria?
ceftriaxone
but you usually give doxycyclin too for the probably concurrent chlamydia infection
What do we use prophylactically in newborns?
erythromycin eye drops
Can neisseria gonorrhoae infect any other species?
nope - obligate human
What are all the clinical presentations of neisseria gonorrhoaea?
- local infection - asymptomatic, urethritis, dysuria, cervicit,s opthalmia neonatorum in infnats
- systemic infection with septic arthritis
c
What are the complications if neisseria is not treated?
PID with risk for ectopic pregnancy and sterility
Fitz-Hugh-Curtis - infection of the liver capsule
What kind of cells does neisseria killw ith its endotoxin?
ciliated cells
How does te neisseria gain access to the liver capsule for Fitx=Hugh-Curtis syndrome?
it can do all the way up through the fallopian tubes into the peritoneal cavity
There are higher incidences of neisseris infection in women who…
are menstruating or have an IUD
Why don’t you get lasting immunity to neisseria?
antigen variation on that pili
Painful blisters and painful lymphagenpathy….
HSV-2
What is the main treatment for HSV_2
acyclovir
What is the risk to a fetus with HSV-2
blindness
disseminated HSV
What smear is used to diagnosed SHV-2? What would you see?
Multinucleated giant cell on Tzanck smear
What kind of herpes virus is HSV-2?
alphaherpesviruses (which includes simplex and vavricella)
CMV is the beta
EBV is the gamma
What type of cell does HSV-2 develop latency in?
neurons
What are the ways to transmit HSV?
direct contact with rash
note VZV can be airborn if alveoli infected
Describe the morphology of HSV
dsDNA linear genome (class 1)
icosahedral
enveloped
What is the most important viral genes for treatment putposes?
thymidine kinase
and viral DNA-dependent DNA polymerase
What type of immunity is essential for the control of HSV?
cell-mediated
How does acyclovir work?
it’ a nuclotide analog that is only activated by viral thymidine kinase, after which it’s further activated by cellular kinases to acyclovir triphosphate which is a chain terminator
Acyclovir is hugely selective. what’s the other reasonf or this besides needing viral thymidine kinase?
has a binding potential for the viral DNA 100x higher than the host cell DNA polymerase
How does resistance to ayclovir come about?
mutations to the thymidine kinase and/or the viral DNA polymerase
What are the three likely causes of vaginal discharge?
bacterial vaginosis - Gardnerella
candida albicans
trichomonas vaginalis
What is the discharge like in bacterial vaginosis?
white to gray, moderate amount, very malodorous
Whati s the discharge like in candida?
itchiness present, discharge typically white, small amount, clumped
cottage cheese
What is the discharge like in trich?
discharge is yellowish - greenish in large amoutns
WHat is included int he diagnostic workup for vaginal discharge?
vaginal pH and a KOH amine test
alsto wet mount and gram stain
WHat is normal vaginal pH?
4.5
If vaginal pH is elevated, what are the two likely possibilities?
trichomoniasies and bacterial vaginosis
What presence of volatil aminds on the KOH amin test suggests which diagnosis?
bacterial vaginosis
What would you see on gram stain in the bacterial vaginosis?
a clue cell - it’s a vaginal epithelial cells covered with attached microorganisms
What would you see on wet mount in trichomonis?
large, pear-shaped motile flagellated protozoa
4 anterior flagella and an undulating membrane of 5 more flagella
What proportion of tric infections are asympoatic?
50%
What symtoms will show up in females?
vaginitis with yellowish green discharge
women who become infected during pregnancy are predisposed to premature labor and low birth weight
chronic infeciton can lead to infertility
True or false: trichomonas is a protozoan, so it has a cyst form?
false - no cyst form and it does not survive long out of the host
True or false: trichomonas, unlike candida, has no opportunistic shifts within the host
true
What’s the drug of choice for trich?
metronidazole
damages DNA in anaerobes
What should show up on wet prep in candida?
few yeast cells and pseudohyphae
THe presence of those pseudohyphae is indicative of what?
that the yeast is growing rapidly and likely causing infection
What groups of women are particularly pronte to active yeast infections?
diabetics
pregnancy women
some prone to this during mentrustion
HIV positive
a small percentage of women with no underlying immune disease can experience chronic or recurrent vaginal infection with candida
What are the drugs used in yeast infections?
topical and oral azole drugs
What other STD makes HIV transmission much more likely?
any ulcerative disease like HSV
Painless ulcers, goes through remission, comes back as a systemic rash including on palmss…
syphilis
How do we confirm syphilis infection?
serology
What bacteria causes syphilis/
treponema pallidum
WHat are the stages of syphilis?
primary secondary and tertiary separated by latent periods
WHen is the person infectious? all the time?
no - only during the primary stage. not during the latent stages
Describe presentation of primary syphilis?
appearancr of a hard painless chancre at the site of pathogen entry
small red, hard bump that enlarges and breaks down to elave a shallow crater with firm margins
the base of the chancre will have organisms for infecting others
What areas are chancres usually located?
genitalis, lips, oral cavity, hipples, fingers or around anus
Describe the presentation of secondary syphilis?
2-6 months after the chacre heals…
fever, headche, sore throat, followed by lymphadenopathy and a rash that breaks out on ALL skin surfaces, including palms and soles of the feet
person’s hair often falls out
What’s actually causing the rash in secondary syphilis?
Type III HSR - immune complex
Describe the presentation of tertiary syphilis.
cardiovascular syphilis - damage to small arteries in aortic wall - can distend and rupture leading to heart failure
formation of gummas - painful swollen syphilitic tumors in liver, skin, bone and cartilage
neurosyphilis - severe headaches, convulsions, atrophy of optic nerve, blindness, dementia, Argyll-Robertson pupil, and spinothalamic tract issues I think (that’s from memory, not on PP)
Can tertiary syphilis be treated?
nope - fatal
fortunately we don’t see it much anymroe because of antibiotics
Describe the presentation of congenital syphilis.
inhibited fetal growth
teeth notching
systemic infections with profuse nasal discharge, skin eruptions, bone deformations and nervos system abnormalities
Describe the morphology of treponema pallidum?
spirochete gram negative bacteria
How do we detect this spirochete?
dark-field microscopy of the suspeted lesion
also do blood tests for the antibody
What are the antigens these antibodies are usually against?
- spirochete atngiens
- cardiolipin antibodies (which is a host cell constituent that the body makes ABs to in a syphilis infection)
detected with VDRL, Kolmer, and Wasserman tests
What is the immunofluorescent method for treponema pallidum
FTA-ABS
fluorescent treponemal antibody absorbance test
What is the drug of choice for syphilis/ how long?
penicillin G for all stages
give parenterally in large doses to maintain blood level lethal to the spirochete for at least 7 days
tetracycline and erythromycin are less effective but can be used in penicillin allergy
