Sexually transmitted infections Flashcards Preview

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Flashcards in Sexually transmitted infections Deck (50):
1

Describe the routes of transmission for STIs?

Oral-genital contact

Vaginal intercourse

Anal intercourse

Anilingus

2

Describe the agent of gonorrhea?

Nesisseria gonorrheae

Gram negative diplococci

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3

What does neisseria gonorrhoeae adhere to in the body to cause infection?

Columnar epithelial cells (line urethra and cervix)

4

Describe the incubation period for gonorrhea?

2-7 days

5

Describe the presentation of gonorrhea?

Asymptomatic common in females (80%)

Urethritis and thick urethral discharge in males

Infection in throat (difficult to distinguish from other causes of pharyngitis)

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6

Describe the antibiotic resistance levels of neisseria gonorrhoeae?

Why does this occur?

Increasing levels of antibiotic resistance

Able to exchange antibiotic resistance genes with other neisseria (eg. meningitidis) that colonise mouth

 

7

Describe the possible consequences of dissemination of gonorrhoea?

In how many cases does this occur?

Dissemination occurs in 0.5-3% if untreated

Arthritis 
Maculopapular rash
Meningitis
Endocarditis
Epididymitis
Peri-hepatitis (Fitz-Hugh-Curtis syndrome)

Pelvic Inflammatory Disease (> tubal scarring, infertility)

8

Describe the symptoms of Pelvic Inflammatory Disease?

Fever

Pelvic tenderness

Discharge

9

Describe the pathology of Fitz-Hugh-Curtis syndrome?

Gonorrhoea > ascends up Fallopian tubes > enters abdominal cavity > liver adhesions > hepatitis> derangement in LFTs

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10

Describe the possible consequences of a mother with gonorrhoea delivering a baby naturally? 

Neonatal gonococcal opthalmia 

Gross purulent conjunctivitis 

If untreated > perforation and blindess

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11

Describe the treatment of neonatal gonococcal opthalmia?

IV cefotaxime for 7 days

Irrigate eyes regularly 

No topical treatment

Also treat mother and sexual contacts

12

Why is it important to distinguish neonatal gonococcal opthalmia from other causes of conjuntivitis?

Different treatments

Other conjunctivitis only requires topical treatments, whereas NGO requires systemic treatment 

NGO can lead to blindness if untreated 

13

Describe the major diagnostic specimens that can be collected for investigation of gonorrhoea?

Cervical swab in charocal transport medium (female)

Urethral swab (male)

First void urine

 

14

Describe the laboratory investigations that can be performed for investigation of gonorrhoea?

CULTURE

Non-selective: CBA in CO2

Selective: Thayer-Martin agar (inhibits growth of normal)

Culture for antibiotic sensitivities

NUCLEIC ACID AMPLIFICATION TESTS 

15

Describe the treatment for gonorrhoea?

Explain?

Ceftriaxone 500mg IV/IM and Azithromycin 1g oral

Combination used to delay emergence of resitance

Azithromycin also treats chlamydia (coinfection common)

16

How can gonorrhoea be prevented?

Barrier contraception 

17

Describe the agent that causes chlamydia?

Chlamydia trachomatis

Obligate intracellular parasite 

Serovars D-K cause genital infection 

18

Describe the different stages of chlamydia trachomatis?

Elementary bodies: infectious, non-replicating, hardy

Reticulate bodies: metabolically active, replicate 

19

Describe the life cycle of chlamydia?

Elementary body infects columnar epithelium of target > reticulate body froms in cell > replication > reticulate bodies reorganise into elementary bodies > elementary bodies released 

48-72 hours 

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20

What is the most common STI?

Chlamydia

21

Describe the presentation of chlamydia?

Females: cervicitis

Males: urethritis

Frequently asymptomatic 

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22

Describe the possible clinical findings for chlamydia?

MALES
Dysuria
Meatal erythema
Clear urethral discharge
Testicular pain
Prostatitis

FEMALES
Cervicitis, endometritis, vaginal discharge
Urethritis/dysuria
Irregular bleeding
Pelvic pain and dyspareunia
PID

23

What is LGV?

Lymphogranuloma venereum

Invasive lymphatic infection caused by chlamydia

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24

How commonly is chlamydia transferred to neonates?

50% transmission

25

Describe the consequences of neonatal chlamydia?

25% conjunctivitis: thin, haemorrhagic

10% pneumonia: 3-4 months incubation, staccato cough

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26

Describe the laboratory investigation of chlamydia?

Sample: cervical/urethral/anal swab or first void urine

Tests: NA detection (not culture)

TEST OF CURE REQUIRED (post procedure and pregnancy)

 

27

When and why is test of cure required in chlamydia?

Post procedure and in pregnancy

Chance of reinfection or lack of response to initial treatment 

28

Describe the treatment for chlamydia?

Azithromycin 1g oral, 2 doses 1 week apart

OR

Doxycycline 100mg oral twice daily, 10-14 days

Severe chlamydia PID: azithromycin 500mg IV daily, 14 days (step down to oral when well)

Treat sexual contacts

Test of cure

Retest

 

29

Describe trichomonas vaginalis?

Sexually transmitted

Flagellated protozoan > motile 

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30

Describe the presentation of infection with trichomonas vaginalis?

Frequently asymptomatic

Frothy, green-yellow vaginal discharge

Pruritis, odour, dysuria, abdominal pain

31

Describe the possible appearance of the cervix after infection with trichomoas vaginalis?

Cervical erythema and friability

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32

Describe the effect of trichomonas vaginalis on the pH of the vagina?

pH > 5

Becomes more alkaline 

33

What is infection with trichomonas vaginalis a marker for?

High risk sexual activity

34

Describe the prevalence of trichomonas vaginalis infection?

Underestimated

About 5% sexually active women

35

Describe a possible consequence of trichomonas vaginalis infection?

How does this occur?

Genital inflammation > doubled risk HIV acquisition 

36

Which groups of people is trichomonas vaginalis infection associated with?

Non-steady partners

Older partners

Marijuana users

Indigenous community

37

Describe the laboratory testing for trichomonas vaginalis?

High vaginal swab > microscopy, culture

Urine > PCR (expensive for this infection)

Sometimes seen on Pap smear

38

Describe the treatment for infection with trichomonas vaginalis?

Metronidazole 2gm orally singly

Tinidazole 2 gm orally singly

Or smaller doses for better SE tolerance 

Treat partners

Follow up testing (may have resistance)

 

39

Why is follow up testing required after treatment of trichomonas vaginalis infection?

May have antibiotic resistance

40

Describe the agent that causes syphilis?

Treponema pallidum 

Spirochaete bacterium

 

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41

Describe the stages of syphilis?

Primary: ulcer (Chancre) on genitals, 2-3 weeks after exposure

Secondary: ulcer heals > rash, lymphadenopathy, abdominal pain, alopecia

Early latency

Late latency

Tertiary: can lead to neurosyphilis

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42

Describe the laboratory testing for syphilis?

Microscopy: difficult to see, don't Gram stain

Serology: non-treponemal and treponemal tests 

43

Describe the non-treponemal tests that are used for investiagting syphilis/t.pallidum?

Ab to cellular lipids and lecithin 

Positive 4-8 weeks post-infection

useful for screening and monitoring therapy 

44

Describe the treponemal tests that are used to investigate syphilis/t.pallidum?

Detect antigens on organism itself

Positive slighlty earlier and for life 

45

Describe mycoplasma genitalium?

Smallest genome 

Newly emerging

No cell wall

Flask shaped (protusion for attachment to columnar mucosa)

Sexually transmitted 

Antibiotic resitant

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46

Describe the prevalence of mycoplasma genitalium?

3-5%

47

What is the main diagnostic tool for mycoplasma genitalium?

Why?

Nucelic acid detection

Difficult to culture
No cell wall > no Gram stain 

48

Describe the presentation of infection with mycoplasma genitalium?

Urethritis (men)

Cervicitis (women)

Acute endometritis

PID

May predispose to HIV transmission 

49

Describe the treatment for mycoplasma genitalium?

Azithromycin 1gm (15-30% failure)

or

Moxifloxacin 400mg daily, 7-10 days (expensive, failures described)

 

50

List the indications for STI testing?

Symptomatic patient investigation

Screening for asymptomatic infection

Pre-pregnancy

Antenatal screening

Blood and organ donation

Contact tracing

Epidemiological surveillance