Sexually Transmissible Infections Flashcards by Srishti D

What are sexually transmissible infections (STIs)?

Infections transmitted primary during sexual contact

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What are the routes of transmission for STIs?

Oral-genital contact
Vaginal intercourse
Anal intercourse
Anilingus

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How are STIs detected?

Microscopy
Culture
Serology
Nucleic acid amplification tests

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What are the 5 P’s of a sexual history?

Partners
- Male/female/both
- Number
Pregnancy prevention
Protection from STIs
Practices
Past history of STIs

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What is the cellular morphology of Neisseria gonorrhoeae?

Intracellular Gram negative diplococci

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What cells do N gonorrhoeae enter and how?

Adhere to columnar epithelial cells via pilli
Enter cells around cervix and urethra
Can also survive in neutrophils

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What is the incubation period for N gonorrhoeae?

2-7 days

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What proportion of infections ins asymptomatic?

80% in females

10% in males

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What symptoms does N gonorrhoeae cause?

Pain

Discharge

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What disseminated diseases can N gonorrhoeae cause?

Arthritis
Maculopapular rash
Meningitis
Endocarditis
Epididymitis
Peri-hepatitis

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When is risk of disseminated disease with N gonorrhoeae greater?

Post menses

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When can pelvic inflammatory disease develop after an gonococcal infection?

1-2 weeks

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What can pelvic inflammatory disease cause?

Tubal scarring

Infertility

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What is neonatal gonococcal ophthalmia?

Gross purulent conjunctivitis

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When does neonatal gonococcal ophthalmia develop?

Day 2-5 of life

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What does neonatal gonoccocal ophthalmia cause?

Mild disease indistinguishable from other causes of conjunctivitis
Perforation of front of eye and blindness

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What is the treatment for gonococcal ophthalmia?

IV cefotaxime, 7 days
Irrigate eyes regularly
Treat mother and sexual contacts

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What specimens can be taken for the diagnosis of gonorrhoea?

Cervical swab into charcoal transport
Male urethral swabs
Urine
Other specimens
- Conjunctiva
- Pharynx
- Skin lesions
- Anal
- CSF
- Blood
- Synovial fluid

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What are the lab investigations for the diagnosis of gonorrhoea?

Non-selective: CHB in CO2
Selective: Thayer-Martin agar
Culture for antibiotic sensitivities

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What antimicrobials are found in Thayer-Martin agar?

Colistin - kills Gram negative bacteria
Vancomycin - kills Gram positive bacteria
Nystatin - kills fungi

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In what proportion of gonorrhoea cases is there a co-infection with chlamydia?

50%

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What is the treatment for gonorrhoea?

Ceftriaxone

Azithryomycin - also kills chlamydia

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How do you prevent gonorrhoea?

Barrier contraception

Contact tracing

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Which organism causes chlamydia?

Chlamydia trachomatis

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What are the signs and symptoms of cervicitis?

``` Swollen Red Friable Columnar epithelium exposed Bleeds easily when touched ```

What is the cellular morphology of C trachomatis?

Obligate intracellular bacteria

What cell type does C trachomatis invade?

Columnar epithelium

What serovars of C trachomatis causes genital infection?

D-K

What serovars of C trachomatis cause lymphogranuloma venereum (LGV)?

L 1-3

What serovars of C trachomatis cause ocular infection (trachoma)?

A-C

How long is the life cycle of C trachomatis?

48-72 hrs

What are the two forms of C trachomatis during its life cycle?

``` Elementary bodies - Infectious - Non-replicating - Hardy Reticulate bodies - Metabolically active - Replicate ```

What is the life cycle of C trachomatis?

1. Attachment and entry of elementary body to target cell 2. Formation of reticulate body 3. Binary fission of reticulate bodies 4. Reorganisation of reticulate bodies into elementary bodies 5. Multiplication ceases 6. Release of elementary bodies

What is the most common STI?

Chlamydia

What does chlamydia cause in males and females?

Males: urethritis Females: cervicitis

Is chlamydia always symptomatic?

No, frequently asymptomatic

What are the clinical findings of chlamydia in males?

``` Dysuria Meatal erythema Clear urethral discharge - Not as purulent as gonorrhoea Testicular pain Prostatitis ```

What are the clinical findings of chlamydia in females?

``` Cervicitis, endometritis/vaginal discharge Urethritis/dysuria Irregular bleeding Pelvic pain and dyspareunia Pelvic inflammatory disease - Acute - Chronic ```

What is LGV?

Invasive lymphatic infection

What are the clinical features of GLV?

Ulcerative genital lesion, similar to chancre of syphilis Suppurative inguinal lymphadenopathy Systemic symptoms Men who have sex with men: proctocolitis

What is proctocolitis?

Inflammation of rectum and colon

Where is LGV endemic?

Africa India Southeast Asia South America

What is the rate of vertical transmission of chlamydia?

50%

What does neonatal chlamydia present as?

Conjunctivitis | Pneumonia

When does conjunctivitis caused by neonatal chlamydia appear?

2-28 days

When does penuomonia caused by neonatal chlamydia appear?

2-8 weeks

What are the lab investigations for the diagnosis of chlamydia?

``` Cervical/urethral/anal swab Urine Nucleic acid detection Test of cure needed - Post-procedure; eg: IUD insertion - Pregnancy ```

What is the mainstay of chlamydia identification?

Nucleic acid detection

Why is chlamydia culture not routine?

Needs cell culture techniques

What is the treatment for chlamydia?

``` Azithromycin, oral OR Doxycycline, oral - Less well tolerated Contact trace partners Notifiable disease Test of cure in 4-6 weeks Advise retest in 3 months ```

What is the treatment for severe chlamydia causing pelvic inflammatory disease?

Azithromycin, IV > step down to oral when well

What can repeated episodes of chlamydia cause?

Scarring

What is the cellular morphology of Trichomonas vaginalis?

Flagellated protozoan

Can you get female to female transmission of T vaginalis?

Yes

Can you get male to male transmission of T vaginalis?

Very rare

Can T vaginalis be asymptomatic?

Yes, frequently

How is T vaginalis transmitted?

Sexually

What are the clinical features of a T vaginalis infection?

``` Vaginal discharge - Frothy - Green-yellow - Smelly, fishy odour Cervical erythema and friability Pruritis Dysuria Abdominal pain ```

What is the presence of T vaginalis a marker for?

High risk sexual activity Possibility of other STIs - Chlamydia - Gonorrhoea

What does the genital inflammation caused by T vaginalis increase the risk of acquiring?

HIV

How does a T vaginalis infection increase the risk of HIV acquisition?

In females: shed more HIV virions | If males HIV positive, females more susceptible

What is a T vaginalis infection associated with?

Non steady partner Older partner Marijuana use

In which demographic does T vaginalis have an increased prevalence?

Indigenous community

What are the lab investigations for T vaginalis?

``` High vaginal swab - Wet prep microscopy to detect motility - Culture Urine - PCR Sometimes seen on Pap smear ```

What is the treatment for T vaginalis?

``` Metronidazole, oral Tinidazole, oral Clindamycin cream Treat partners Follow up testing ```

Why is follow up testing required after treatment for a T vaginalis infection?

May have resistance

What is the causative organism of syphilis?

Treponema pallidum

What are the clinical features of primary syphilis?

Lesions at site of inoculation on mucous membranes 5 weeks after inoculation Chancres = painless ulcers

What are the clinical features of secondary syphilis?

``` 3-6 months after primary lesions healed Fever Rash Alopecia Some hepatitis ```

What are the stages of syphilis?

``` Primary Secondary Early latent Late latent Tertiary ```

How is T pallidum detected in the lab?

``` Microscopy - Hard to see on light microscopy - Can use dark field microscopy Serology - Non-treponemal tests - Treponemal tests ```

What non-treponemal test is used regularly?

RPR

Describe non-treponemal tests

Abs to cellular lipids and lecithin Positive 4-8 weeks post infection 70% positive within 2 weeks of chancre 100% positive fr secondary and latent

What are non-treponemal tests useful for?

Diagnosis | Monitoring therapy

What can cause false positive reactions in non-treponemal tests?

Connective tissue disorders Viral infections IV drug use Pregnancy

What can cause false negative reactions in non-treponemal tests?

Prozone effect | - Excess Abs can give negative results

What are treponemal tests used for?

Screening

What is the most regularly used treponemal test?

EIA

What doesn't Mycoplasma genitalium have which other bacteria doo?

Cell wall

Can M genitalium be cultured?

Not easily - Fastidious - Difficult to culture > takes 1-2 months to grow

What is the mainstay of diagnosis of M genitalium?

NAAT

What samples are used for the diagnosis of M genitalium?

Ist void urine | Vaginal swab

How is M genitalium transmitted?

Sexually

What is the antibiotic susceptibility of M genitalium?

Antibiotic resistant

What is the clinical presentation of M genitalium?

``` Males: urethritis - 50% asymptomatic Females - Cervicitis - Acute endometritis - Pelvic inflammatory disease, especially post termination of pregnancy ```

How long can an M genitalium infection persist for?

3-6 months

What may an M genitalium infection predispose you to?

HIV transmission

How can azithromycin resistance be tested for in M genitalium?

Whilst doing NAAT

What is the treatment for an M genitalium infection?

Azithromycin

What is the failure rate of azithromycin as a treatment for an M genitalium infection?

15%

What can be used in treatment if M genitalium is resistant?

Moxifloxacin

What are the limitations of the use of moxifloxacin?

Expensive Failures described Not safe in pregnancy

What are the indications for STI testing?

``` Symptomatic patient Screening for asymptomatic infection Pre-pregnancy Antenatal screening Blood and organ donation Contact tracing Epidemiological surveillance ```

Sexually Transmissible Infections Flashcards

(93 cards)