Sexually transmitted infections Flashcards

1
Q

Describe the routes of transmission for STIs?

A

Oral-genital contact

Vaginal intercourse

Anal intercourse

Anilingus

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2
Q

Describe the agent of gonorrhea?

A

Nesisseria gonorrheae

Gram negative diplococci

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3
Q

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

A

Columnar epithelial cells (line urethra and cervix)

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4
Q

Describe the incubation period for gonorrhea?

A

2-7 days

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5
Q

Describe the presentation of gonorrhea?

A

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
Q

Describe the antibiotic resistance levels of neisseria gonorrhoeae?

Why does this occur?

A

Increasing levels of antibiotic resistance

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

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7
Q

Describe the possible consequences of dissemination of gonorrhoea?

In how many cases does this occur?

A

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)

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8
Q

Describe the symptoms of Pelvic Inflammatory Disease?

A

Fever

Pelvic tenderness

Discharge

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9
Q

Describe the pathology of Fitz-Hugh-Curtis syndrome?

A

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

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10
Q

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

A

Neonatal gonococcal opthalmia

Gross purulent conjunctivitis

If untreated > perforation and blindess

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11
Q

Describe the treatment of neonatal gonococcal opthalmia?

A

IV cefotaxime for 7 days

Irrigate eyes regularly

No topical treatment

Also treat mother and sexual contacts

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12
Q

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

A

Different treatments

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

NGO can lead to blindness if untreated

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13
Q

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

A

Cervical swab in charocal transport medium (female)

Urethral swab (male)

First void urine

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14
Q

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

A

CULTURE

Non-selective: CBA in CO2

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

Culture for antibiotic sensitivities

NUCLEIC ACID AMPLIFICATION TESTS

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15
Q

Describe the treatment for gonorrhoea?

Explain?

A

Ceftriaxone 500mg IV/IM and Azithromycin 1g oral

Combination used to delay emergence of resitance

Azithromycin also treats chlamydia (coinfection common)

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16
Q

How can gonorrhoea be prevented?

A

Barrier contraception

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17
Q

Describe the agent that causes chlamydia?

A

Chlamydia trachomatis

Obligate intracellular parasite

Serovars D-K cause genital infection

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18
Q

Describe the different stages of chlamydia trachomatis?

A

Elementary bodies: infectious, non-replicating, hardy

Reticulate bodies: metabolically active, replicate

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19
Q

Describe the life cycle of chlamydia?

A

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
Q

What is the most common STI?

A

Chlamydia

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21
Q

Describe the presentation of chlamydia?

A

Females: cervicitis

Males: urethritis

Frequently asymptomatic

22
Q

Describe the possible clinical findings for chlamydia?

A

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
Q

What is LGV?

A

Lymphogranuloma venereum

Invasive lymphatic infection caused by chlamydia

24
Q

How commonly is chlamydia transferred to neonates?

A

50% transmission

25
Q

Describe the consequences of neonatal chlamydia?

A

25% conjunctivitis: thin, haemorrhagic

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

26
Q

Describe the laboratory investigation of chlamydia?

A

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

Tests: NA detection (not culture)

TEST OF CURE REQUIRED (post procedure and pregnancy)

27
Q

When and why is test of cure required in chlamydia?

A

Post procedure and in pregnancy

Chance of reinfection or lack of response to initial treatment

28
Q

Describe the treatment for chlamydia?

A

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
Q

Describe trichomonas vaginalis?

A

Sexually transmitted

Flagellated protozoan > motile

30
Q

Describe the presentation of infection with trichomonas vaginalis?

A

Frequently asymptomatic

Frothy, green-yellow vaginal discharge

Pruritis, odour, dysuria, abdominal pain

31
Q

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

A

Cervical erythema and friability

32
Q

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

A

pH > 5

Becomes more alkaline

33
Q

What is infection with trichomonas vaginalis a marker for?

A

High risk sexual activity

34
Q

Describe the prevalence of trichomonas vaginalis infection?

A

Underestimated

About 5% sexually active women

35
Q

Describe a possible consequence of trichomonas vaginalis infection?

How does this occur?

A

Genital inflammation > doubled risk HIV acquisition

36
Q

Which groups of people is trichomonas vaginalis infection associated with?

A

Non-steady partners

Older partners

Marijuana users

Indigenous community

37
Q

Describe the laboratory testing for trichomonas vaginalis?

A

High vaginal swab > microscopy, culture

Urine > PCR (expensive for this infection)

Sometimes seen on Pap smear

38
Q

Describe the treatment for infection with trichomonas vaginalis?

A

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
Q

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

A

May have antibiotic resistance

40
Q

Describe the agent that causes syphilis?

A

Treponema pallidum

Spirochaete bacterium

41
Q

Describe the stages of syphilis?

A

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

42
Q

Describe the laboratory testing for syphilis?

A

Microscopy: difficult to see, don’t Gram stain

Serology: non-treponemal and treponemal tests

43
Q

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

A

Ab to cellular lipids and lecithin

Positive 4-8 weeks post-infection

useful for screening and monitoring therapy

44
Q

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

A

Detect antigens on organism itself

Positive slighlty earlier and for life

45
Q

Describe mycoplasma genitalium?

A

Smallest genome

Newly emerging

No cell wall

Flask shaped (protusion for attachment to columnar mucosa)

Sexually transmitted

Antibiotic resitant

46
Q

Describe the prevalence of mycoplasma genitalium?

A

3-5%

47
Q

What is the main diagnostic tool for mycoplasma genitalium?

Why?

A

Nucelic acid detection

Difficult to culture
No cell wall > no Gram stain

48
Q

Describe the presentation of infection with mycoplasma genitalium?

A

Urethritis (men)

Cervicitis (women)

Acute endometritis

PID

May predispose to HIV transmission

49
Q

Describe the treatment for mycoplasma genitalium?

A

Azithromycin 1gm (15-30% failure)

or

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

50
Q

List the indications for STI testing?

A

Symptomatic patient investigation

Screening for asymptomatic infection

Pre-pregnancy

Antenatal screening

Blood and organ donation

Contact tracing

Epidemiological surveillance