STIs

Question 1

What are the most common incidence and prevalence STIUs according to the CDC?

Answer 1

Prevalence = number of STIs at any given point in the population

1) HPV
2) HSV-2
3) trichomoniasis

Incidence = number of STIs acquired in the year

1) HPV
2) Trichomoniasis
3) chlamydia

Question 2

What are genital diseases and genital infections that are NOT sexually transmitted

Answer 2

Diseases:

• TB
• Leishmaniasis
• Histoplasmosis

Infections:

• bacterial vaginosis
• candidiasis

Question 3

What STIs are transmitted in utero and during brith?

Answer 3

In utero

• HIV
• syphills
• HSV 1/2

In birth

• HSV 1/2
• Gonnorhea
• chlamydia

Question 4

Chlamydia trachomatis

Answer 4

Small obligate intracellular parasite that has two unique forms
- gram (-) cocci that dont stain well

1) elementary bodies
- infections form and are extracellular but metabolically Inactive

2) reticulate bodies
- growth form that are intracellular and metabolically active

There are different serotypes with different tropism/disease
- this is based exclusively on the present of what Major Outer Membrane Protien (MOMP) is present

Treatment = 250mg doxycycline PO for 10-14 days

Question 5

Typical chlamydia

Answer 5

Serotype D-K

Usually incubates for 5-14 days

Produces an acute inflammatory response with Purulent exudate
- also produces a pro- inflammation cytokine response to infection

Clinical symptoms in females

• cervicitis (mucopurulent odorous discharge with pain and low grade fever)
• urethritis (dysuria and frequent urination)
• DOESNT usually induce symptoms of proctitis

Clincial symptoms in males: (25% = fully asymptomatic)

• urethritis (dysuria and frequency but also mucoid or clear discharge)
• epididymitis (unilateral testicular pain and tenderness with a hydrocele often present)
• *much more common than gonorrhea**
• prostitis (pelvic pain, pain with ejaculation and dysuria)
• proctitis (usually asymptomatic also)

Question 6

Neisseria gonorrhea

Answer 6

Gram negative diplococci that is a facultative intracellular pathogen

• oxidase and catalase (+)
• NON-encapsulated
• very easy staining
• grows on Thayer-Martin agar

Contains a couple of high yield virulence factors

• type 4 pili = “twitching motility” and allow for antigenic variation
• Opa protiens
• LOS = broad inflammation
• Porins = allows to invade cells
• IgA proteases

Treatment:

• uncomplicated = ceftriaxone 250-500mg IM 1x period
• complicated (cant rule out concomitant chlamydia) = add doxycycline PO 250 mg for 10-14 days
• • if disseminated = add azithromycin 500mg PO 1x period to ceftriaxone treatment

Question 7

Gonorrhea symptoms in males and females

Answer 7

Females: takes 10 days to incubate. Also more likely to disseminate

• cervicitis ( 70% is asymptomatic for this. Friable Cervical mucosa, mucopurulent discharge, NO PAIN unless PID is concomitant)
• urethritis (dysuria, frequency and urgency)
• Bartholinits (perilabial pain and discharge)
• proctitis (tenesmus, anorectal pain and rectal fullness, can be asymptomatic thou)

Males: takes 2-7 days to incubate. Also less likely to disseminate

• urethritis = 60% asymptomatic, Purulent corpus discharge (often shows “bull-headed clap” appearance on periurethral area), dysuria but NO urgency or frequency
• epididymitis = unilateral testicular pain and swelling (often is presenting compliant)
• proctitis (only in MSM relationships, can show tenesmus, anorectal pain, rectal fullness and bleeding)

Question 8

Trichomoniasis vaginalis

Answer 8

Protozoan that possess flagellate
- are pear shaped with 4 flagella and an undulating membrane

Incubation = 4-28 days

Clinical symptoms in females:

• vaginitis/vulvitis (painful inflammation with frothy green-yellow malodorous discharge)
• *will show punctate hemorrhages on vagina and cervix (“strawberry cervix”)**
• dyspareunia, dysuria, post coital bleeding

Clincial symptoms in males

• 75% = asymptomatic
• urethritis with clear/mucopurulent discharge and dysuria only

Treatment :
- PO metronidazole 500mg 1 time period or tinidazole PO 2g 1x period

Question 9

Herepes simplex virus

Answer 9

Enveloped icosahedral DsDNA virus
- shows latent and asymptotic shedding since there are no viral protiens

HSV 1 = usually oral
HSV 2 = usually genital and tends to be severe

always produces intranucelar inclusions and giant cells on Zsank smears

Primary symptoms (while active/none latent)

• systemic symptoms
• local pain and itching with small yellow papules that may rupture/blister
• dysuria
• tender lymphadenopathy
• *if symptoms are present, this also means no antibodies are formed yet**

Treatment:
- 1st line = PO acyclovir or Foscarnet (if acyclovir resistant strains).

Question 10

Syphilis

“Treponema pallidum”

Answer 10

Is a spirochete gram (-) Maribor

• microareophiles that cant be cultured in vitro
• catalase and superoxide dismutase (-)
• is very labile to heat

must use immunoflurorescence for imaging

Virulence factors

• endoflagella = “corkscrew motility”
• outer membrane proteins = allow for adherence with little immunogenicity properties (“stealth organism”)

There are 3 stages of syphilis

Treatment = penicillin G
- primary or secondary = IM, for 1 dose period tertiary = IV for 10-14 days

Question 11

Three stages of syphills

Answer 11

1) primary: 9-90 days after infection
- shows chancre (painless ulcers with raised border) these disappear within 3-6 weeks
- if anal chancre = will be a painful
- regional lymphadenopathy

2) Secondary: 2-8 weeks after chancre goes away
- shows all of primary symptoms + palmar rash, disseminated lymphadenopathy, condyloma Latium and asymptomatic neuro syphilis.
- also flu-like illness and potentially “moth-eaten” alopecia

3) tertiary: years-decades after inital infection
- shows all of secondary + symptomatic neurosyphills (Charcot joints, tabes dorsalis (loss of positional sense due to spinal column lesions) ataxia and insanity), aortitis (destruction of aorta) and “gummas” (usually only seen in concurrent HIV but are soft masses filled with treponema species that often destroy surrounding tissues)

Question 12

Lymphogranuloma venereum

Answer 12

Is a subset stage of primary claymdia

Only seen in serotypes L1/2/2a/3
- really only endemic to West Indies, africa and South America

Characterized by painless ulcers on genitals and rectum which leads to excessively large regional lymphadenopathy and lymphedema

3 stages of this

1) described above = primary
2) inguinal syndrome occurs (development of buboes which are painful lymphadenopathy that is unilateral and ulcerates. Also if anorectal = these symptoms begin)
3) late tertiary = genital elephantiasis/esthiomene (enlarged deformed external genitalia of male and females respectively), anal fistula and strictures

Question 13

Chancroid

“Haemophilus ducreyi

Answer 13

Gram negative cocobacilli that is endemic to tropical and developing nations
- also high risk in MSM and sex worker populations

Develops chancroid ulcers everytime

• painful ragged edged papules -> pustule -> ulcers that have a white/yellow base and bleed when touched.
• also often shows inguinal lymphadenopathy

Treatment = PO 500mg azithromycin 1x period or IM 250mg ceftriaxone 1x period.

Question 14

Human papillomavirus (HPV)

Answer 14

Nonenveloped icosahedral capsid DsDNA virus that goes “papilloma” warts

Early genes = E6/E7 = key transforming genes
Late genes = L1 = major viral capsid and is the vaccine target
there is a vaccine

Highly linked with cervical cancer

Over 100 different serotypes

• highest risk for cancers = 16/18/31/33
• anogenital wart most common = 6 and 11

Treatment = imiquimod**

Question 15

3 vaccines for HPV

Answer 15

1) bivalent
- used for HPV 16 and 18 only

2) quadrivalent
- used for HPV 16 and 18
- used for 6 and 11 also

3) nonovalent
- used for 16 and 18
- used for 1 and 11
- used for 31,33,45,52,58 also

All are approved for use in patients 11-45 (can start at 9 if high risk)