Sexually transmitted diseases Flashcards
Bacterial vaginosis
Refers to an overgrowth of bacteria in the vagina, specifically anaerobic bacteria. It is not a sexually transmitted infection.
The loss of what bacteria causes Bacterial vaginosis?
Loss of the lactobacilli “friendly bacteria” in the vagina. Bacterial vaginosis can increase the risk of women developing sexually transmitted infections.
What bacteria is the main componenet of healthy vaginal bacterial flora?
Lactobacilli which produce lactic acid & keeps the vaginal pH low (under 4.5). The acidic environment prevents other bacteria from overgrowing. When there are reduced numbers of lactobacilli in the vagina, the pH rises. This more alkaline environment enables anaerobic bacteria to multiply.
How does Lactobacilli keep the vagina healthy?
Lactobacilli which produce lactic acid & keeps the vaginal pH low (under 4.5).
The acidic environment prevents other bacteria from overgrowing. When there are reduced numbers of lactobacilli in the vagina, the pH rises. This more alkaline environment enables anaerobic bacteria to multiply.
Examples of anaerobic bacteria associated with bacterial vaginosis
- Gardnerella vaginalis (most common)
- Mycoplasma hominis
- Prevotella species
Risk factors for bacterial vaginosis
- Multiple sexual partners
- Excessive vaginal cleaning (douching, use of cleaning products and vaginal washes)
- Recent antibiotics
- Smoking
- Copper coil
Symptoms of bacterial vaginosis
Fishy-smelling watery grey or white vaginal discharge.
Half of women with BV are asymptomatic.
Itching, irritation and pain are not typically associated with BV and suggest an alternative cause or co-occurring infection.
Investigations in bacterial vaginosis
A speculum examination
Vaginal pH can be tested using a swab and pH paper. BV occurs with a pH > 4.5.
A standard charcoal vaginal swab can be taken for microscopy. This can be a high vaginal swab taken during a speculum examination or a self-taken low vaginal swab.
Bacterial vaginosis gives “clue cells” on microscopy.
What are clue cells?
Clue cells are epithelial cells from the cervix that have bacteria stuck inside them, usually Gardnerella vaginalis.
Specific to bacterial vaginosis
Whats the normal vaginal pH?
The normal vaginal pH is 3.5 – 4.5.
Microscopy changes in bacterial vaginosis
“Clue cells” on microscopy.
Management of bacterial vaginosis
Asymptomatic BV does not usually require treatment.
Metronidazole is the antibiotic of choice for treating bacterial vaginosis.
Always assess the risk of additional pelvic infections, with swabs for chlamydia and gonorrhoea where appropriate.
Provide advice and information about measures that can reduce the risk of further episodes of bacterial vaginosis,
What advice should be given to patients when prescribing Metronidazole?
Avoid alcohol for the duration of treatment.
Alcohol and metronidazole can cause a “disulfiram-like reaction”, with nausea and vomiting, flushing and sometimes severe symptoms of shock and angioedema.
Why should alcohol not be taken with metronidazole?
Alcohol and metronidazole can cause a “disulfiram-like reaction”, with nausea and vomiting, flushing and sometimes severe symptoms of shock and angioedema.
Complications of bacterial vaginosis
Increase the risk of catching STIs
Also associated with several complications in pregnant women
Complications of bacterial vaginosis in pregnant women
- Miscarriage
- Preterm delivery
- Premature rupture of membranes
- Chorioamnionitis
- Low birth weight
- Postpartum endometritis
Candidiasis
Commonly referred to as “thrush”. It refers to vaginal infection with a yeast of the Candida family. The most common is Candida albicans.
Most common organism to cause Candidasis
Candida albicans
Risk factors for candidiasis
- Increased oestrogen (higher in pregnancy, lower pre-puberty and post-menopause)
- Poorly controlled diabetes
- Immunosuppression (e.g use of corticosteriods)
- Broad-spectrum antibiotics
Presentation of candidiasis
Thick, white discharge that does not typically smell
Vulval and vaginal itching, irritation or discomfort
Investigations for candidiasis
Testing the vaginal pH using a swab and pH paper can be helpful in differentiating between bacterial vaginosis and trichomonas (pH > 4.5) and candidiasis (pH < 4.5).
A charcoal swab with microscopy can confirm the diagnosis.
Management options in candidiasis
Antifungal cream (i.e. clotrimazole) inserted into the vagina with an applicator
Antifungal pessary (i.e. clotrimazole)
Oral antifungal tablets (i.e. fluconazole)
What is Canesten Duo?
It contains a single fluconazole tablet and clotrimazole cream to use externally for vulval symptoms (e.g. in candidiasis)
They also recommend recurrent infections (more than 4 in a year) can be treated with an induction and maintenance regime over six months with oral or vaginal antifungal medications. This is an off-label use.
What advice should be given to women taking anti-fungal creams and pessaries?
Can damage latex condoms and prevent spermicides from working, so alternative contraceptive is required for at least five days after use.
Chlamydia
Chlamydia is the most common sexually transmitted infection in the UK and a significant cause of infertility - caused by Chlamydia trachomatis
Chlamydia trachomatis
A gram-negative bacterium. It is an intracellular organism, meaning it enters and replicates within cells before rupturing the cell and spreading to others. Causes Chlamydia
National Chlamydia Screening Programme (NCSP).
Aims to screen every sexually active person under 25 years of age for chlamydia annually or when they change their sexual partner.
Everyone that tests positive should have a re-test three months after treatment.
What diseases are tested for in STI screening in GUM clinics?
- Chlamydia
- Gonorrhoea
- Syphilis (blood test)
- HIV (blood test)
Charcoal swabs
Allow for microscopy, culture and sensitivities (testing which antibiotics are effective against the bacteria).
The transport medium is called Amies transport medium and contains a chemical solution for keeping microorganisms alive during transport.
Charcoal swabs can be used for endocervical swabs and high vaginal swabs (HVS).
Nucleic acid amplification tests (NAAT) use in men and women
In women, a NAAT test can be performed on a vulvovaginal swab (a self-taken lower vaginal swab), an endocervical swab or a first-catch urine sample.
In men, a NAAT test can be performed on a first-catch urine sample or a urethral swab.
Rectal and pharyngeal NAAT swabs can also be taken to diagnose chlamydia in the rectum and throat. Consider these swabs where anal or oral sex has occurred.
What is the Nucleic acid amplification tests (NAAT)?
Nucleic acid amplification tests (NAAT) check directly for the DNA or RNA of the organism. NAAT testing is used to test specifically for chlamydia and gonorrhoea.
Chlamydia presentation in women
Most are asymptomatic. Abnormal vaginal discharge Pelvic pain Abnormal vaginal bleeding Painful sex (dyspareunia) Painful urination (dysuria)
Dysuria
Painful urination
Dyspareunia
Painful sex
Presentation of Chlamydia in men
- Urethral discharge or discomfort
- Painful urination (dysuria)
- Epididymo-orchitis
- Reactive arthritis
Examination findings in chlamydia
- Pelvic or abdominal tenderness
- Cervical motion tenderness (cervical excitation)
- Inflamed cervix (cervicitis)
- Purulent discharge
Investigations for chlamydia
NAAT are used to diagnose chlamydia. This can involve a:
• Vulvovaginal swab
• Endocervical swab
• Urethral swab in men
• Rectal swab (after anal sex)
• Pharyngeal swab (after oral sex)
• First-catch urine sample (in women or men)
Management of chlamydia
First-line for uncomplicated chlamydia infection is doxycycline 100mg twice a day
Doxycycline is contraindicated in pregnancy and breastfeeding. Alternatives options for treatment in pregnant or breastfeeding women are:
- Azithromycin 1g stat then 500mg once a day for 2 days
- Erythromycin 500mg four times daily for 7 days
- Erythromycin 500mg twice daily for 14 days
- Amoxicillin 500mg three times daily for 7 days
Complications from chlamydia
- Pelvic inflammatory disease
- Chronic pelvic pain
- Infertility
- Ectopic pregnancy
- Epididymis-orchitis
- Conjunctivitis
- Lymphogranuloma venereum
- Reactive arthritis
Pregnancy-related complications of chlamydia
- Preterm delivery
- Premature rupture of membranes
- Low birth weight
- Postpartum endometritis
- Neonatal infection (conjunctivitis and pneumonia)
Lymphogranuloma venereum (LGV)
A condition affecting the lymphoid tissue around the site of infection with chlamydia. It most commonly occurs in men who have sex with men (MSM).
The three stages of Lymphogranuloma venereum (LGV)
The primary stage involves a painless ulcer (primary lesion).
The secondary stage involves lymphadenitis. This is swelling, inflammation and pain in the lymph nodes infected with the bacteria.
The tertiary stage involves inflammation of the rectum (proctitis) and anus. Proctocolitis leads to anal pain, change in bowel habit, tenesmus and discharge.
Tenesmus
A feeling of needing to empty the bowels, even after completing a bowel motion.
Chlamydial conjunctivitis
Conjunctival infection is usually as a result of sexual activity, when genital fluid comes in contact with the eye.
It presents with chronic erythema, irritation and discharge lasting more than two weeks. Most cases are unilateral.
Chlamydial conjunctivitis occurs more frequently in young adults. It can also affect neonates with mothers infected with chlamydia.
Neisseria gonorrhoeae
Gram-negative diplococcus bacterium.
It infects mucous membranes with a columnar epithelium, such as the endocervix in women, urethra, rectum, conjunctiva and pharynx.
It spreads via contact with mucous secretions from infected areas.
Gonorrhoea
A sexually transmitted infection. Being young, sexually active and having multiple partners increases the risk of infection with gonorrhoea. Having other sexually transmitted infections, such as chlamydia or HIV, also increases the risk.
Presentation of gonorrhea in women
Infection with gonorrhoea is more likely to be symptomatic than infection with chlamydia.
• Odourless purulent discharge, possibly green or yellow
• Dysuria
• Pelvic pain
Presentation of gonorrhea in men
- Odourless purulent discharge, possibly green or yellow
- Dysuria
- Testicular pain or swelling (epididymis-orchitis)
Why are both NAAT tests and charcoal swabs required for diagnosis of gonorrhea?
It is worth remembering that NATT tests are used to check if a gonococcal infection is present or not by looking for gonococcal RNA or DNA. They do not provide any information about the specific bacteria and their antibiotic sensitivities and resistance.
This is why a standard charcoal swab for microscopy, culture and sensitivities is so essential, to guide the choice of antibiotics to use in treatment.