Sexually Transmitted Infection Flashcards by James Nicolson

Commonest STI?

Chlamydia

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Chlamydia trachomatis appearance on gram stain

Obligate intracellular organism

Doesn’t stain on gram stain

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What is Chlamydia trachomatis divided into?

What is the clinical implication of this?

Serovars

Serovars A-C = eye infection

Serovars D-K = genital infection

Serovars L1-3 = lymphogranuloma venereum

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Symptoms of chlamydia?

Pain

Dysuria/Dyspareunia

Vaginal bleeding (post-coital/intermenstrual)

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How long does chlamydia take to show symptoms?

Might never show symptoms

Commonly asymptomatic

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What microorganism is responsible for chlamydia infection?

chlamydia trachomatis

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chlamydia is always sexually transmitted. true or false?

False

Mothers can transfer to neonates during childbirth

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How does neonatal chlamydia present?

Conjunctivitis

Pneumonia

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What is lymphogranuloma venereum?

What microoganism causes it?

Chlamydia infection of lymphatics

Occurs when microbe crosses anal mucous membrane and is taken up by lymphatics

chlamydia trachomatis L1,2,3

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Man presents with dysuria 4 months after successful treatment of an STI.

Diagnosis?

What else would be expect to see?

What do you think the STI was?

Reactive arthritis

Arthritis, conjunctivitis, urethritis

Chlamydia

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First and second line treatments for chlamydia.

1st: doxycycline (7 days)
2nd: azithromycin (3 days)

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What organism causes gonorrhoea?

Neisseria gonorrhoeae

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Neisseria gonorrhoeae appearance on gram stain.

Gram negative intracellular diplococcus

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What organism can be cultured on chocolate agar?

Neisseria gonorrhoeae

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Presentation of gonorrhoea.

Discharge (vaginal, urethral pus)
Pain
Dysuria

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First and second line treatments for gonorrhoea.

1st: IM ceftriaxone
2nd: oral cefixime

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What do these viruses cause?

HSV-1
HSV-2
HPV-6
HPV-11

HSV-1: genital herpes
HSV-2: genital herpes
HSV-6: genital warts
HSV-11: genital warts

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What makes someone with HSV infectious?

Viral shedding

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What HSV virus most commonly undergoes viral shedding?

What is the clinical implication of this?

HSV-2

In general, this means they are more contagious (particularly in first year of infection)

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Why must a patient be symptomatic when they are viral shedding?

They don’t have to be
This isn’t true

Viral shedding can occur asymptomatically

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How does primary genital herpes infection present?

Painful blistering

Pain, dysuria, discharge

Systemic symptoms

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How do you diagnose genital herpes?

Swab re-roofed ulcer for PCR

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Why can genital herpes be recurrent?

Migrates to dorsal root ganglion

How do you treat primary genital herpes infection?

oral acyclovir (lignocaine for pain)

How does a relapse of genital herpes infection present?

Small unilateral ulcers Mild tingling Few systemic symptoms

How do you manage a patient with herpes in pregnancy?

Treat all herpes with acyclovir during pregnancy If history of recurrent infection, treat prophylactically from 36 weeks gestation

What microbe is responsible for syphilis infection?

Treponema pallidum

How does treponema pallidum appear on gram stain?

Doesn't stain on gram stain Spirocheate organism

Describe the stages of syphilis infection and when they occur.

Primary: painless chancre at site of contact (~2 weeks post infection) Secondary: erythematous palmoplantar rash, snail track ulcers and flu (~4 months post infection and pass over a few weeks) Latent: asymptomatic (can last decades) Late: life threatening cardiovascular and neurological damage (long time after initial infection)

What is the simplest test to do in suspected syphilis?

Swab chancre for PCR

What blood tests can you order for suspected syphilis? What do they tell you?

IgM/IgG ELISA test - screening test TPPA/TPHA (treponema pallidum particule/haem-agglutination assay) - positive result confirms infection - may be positive for life after infection VDRL/RPR (venereal disease research laboratory test / rapid plasma reagin) - non specific test - used to monitor treatment response

Dark ground microscopy can be used to see which type of organism?

Treponema pallidum

Management of syphilis.

IM benzathine benzylpenicillin | long acting

5% of people with HPV ___ infection go onto develop genital warts. True/false?

False 1% ____ = 6/11

How do you manage genital warts?

Topical podophyllotoxin Screen for other STIs

Viruses causing - genital warts - genital herpes

warts: HPV 6/11 herpes: HSV 1/2

Increased sexual partners increases risk of bacterial vaginosis. True/false?

True Not a sexually transmitted infection but lots of partners increases risk

What are the normal vaginal flora?

Lactobacilli Produce lactic acid

What do the normal vaginal flora produce and what does this do?

Lactobacilli produce lactic acid to suppress growth of other microbes

What can be seen on microscopy in bacterial vaginosis?

Lactobacilli replaces by clumps of coccobacilli Clue cells - clumps obscure edges of vaginal epithelial cells

How do you treat bacterial vaginosis?

Metronidazole

In what infection would you consider the whiff test? What does it involve and show?

Bacterial vaginosis Adding potassium hydroxide to vaginal discharge produces fishy odour

How does bacterial vaginosis present?

Vaginal discharge

What microorganism causes trichomoniasis?

Trichomonas vaginalis | Single celles protozoa

In what condition might you see an alkaline vagina? What is the normal pH?

Trichomoniasis (pH>5) 3.5-4.5

How might trichomoniasis present?

Vaginal discharge (thin, frothy, fishy) Itchy vagina

How do you treat trichomoniasis?

Metronidazole

What is the name of the emerging sexually transmitted pathogen which may be a big problem in the future?

Mycoplasma Genitalium

What is PID and what causes it?

• Ascending infection of the female reproductive tract Chlamydia, gonorrhoea (bacterial vaginosis)

How does PID present?

In a very varied way (from asymptomatic to severe) Pelvic pain, abnormal discharge, fever, N+V

How do you treat PID?

Metronidazole + ofloxacin

What is the nucleic acid amplification test (NAAT)? What does it test for?

Sensitive PCR test Both chlamydia/gonorrhoea in one test

Where would you take the sample from in NAAT from - male? - female? Where else might you swab and why?

M: first pass urine F: vuvlovaginal swab Rectum, pharynx (MSM) Although asympomatic, pharngeal gonococcal infection sustains gonorrhoea infection in general population

"2 kidney beans" on microscopy?

Gonorrhoea

Benefits/disadvantages of NAAT v culture?

Benefts - NAAT is more sensitive - culture can test for antimicrobial resistance Disadvantages - difficult to grow on culture

What infection requires a test of cure?

Gonorrhoea