Sexually Transmitted Diseases (STDs)

Chlamydia

This is a condition which is caused by the bacteria Chlamydia trachomatis.

It is the commonest sexually transmitted disease in the UK.

It is spread through all types of sex and can be passed to the baby during childbir

Symptoms 

Often the infection is asymptomatic

In females, can cause vaginal bleeding, discharge and deep dyspareunia

In males, can cause urethritis (dysuria and discharge)

Eye disease – can cause blindness

Joints – often a cause of reactive arthritis

Risk factor for pelvic inflammatory disease (PID) in women, leading to infertility

Key tests

Investigation of choice is nuclear acid amplification tests (NAAT)

In women – 1st line is vulvovaginal swab (not urine or cervical swab)

In men – 1st line is urine test

Management

Antibiotics – oral doxycycline (for 7 days) or oral azithromycin (1 to 2 days)

If pregnant – azithromycin, erythromycin or amoxicillin

Gonorrhoea

This is due to the bacteria Neisseria gonorrhoeae, a Gram-negative diplococcus.

It gives similar symptoms to chlamydia, with additional complications.

There is no vaccine available, and reinfection is common due to antigenic variation.

Symptoms

In females, can cause vaginal bleeding, discharge, and deep dyspareunia

In males, can cause urethritis (dysuria and discharge) and urethral strictures

Can also cause infections of the rectum and the pharynx

Complications

Disseminated gonococcal infection (due to the spread of bacteria in the bloodstream from the genitals). Initially gives tenosynovitis, migratory polyarthritis and dermatitis

Fitz-Hugh-Curtis syndrome – inflammation of the liver capsule and RUQ pain

Key tests

Nuclear acid amplification tests (NAAT) of vulvovaginal swab or urine (used in men)

Management

1st line is single dose intramuscular ceftriaxone

If the strain is known to be sensitive to oral ciprofloxacin, a single dose of ciprofloxacin can be given

Syphilis

This is a condition due to Treponema pallidum, a spirochete bacterium.

It is transmitted by sexual contact or during pregnancy from the mother to her baby.

The infection consists of three stages, that increases in severity.

Symptoms

Primary (2–6 weeks)

Chancre (painless ulcer) at site of sexual contact and local painless lymphadenopathy

Secondary (6–10 weeks)

Rashes, particularly affecting the trunk, palms and soles of feet

Erosions that occur in linear streaks in the mouth known as “snail track” ulcers

Systemic signs of infections (fatigue, lethargy, pyrexia)

Condylomata lata (non-tender lesions resembling verrucas on the genitalia)

Tertiary (3–15 years)

CNS involvement – dorsal column syndrome (loss of proprioception and vibration)

Argyll Robertson pupil – this is a pupil which can accommodate but not constrict

Aortic aneurysms

Gummas (granuloma lesions of skin))

Key tests

Direct test for syphilis is PCR or dark-field microscopy

Serological tests for syphilis include treponemal antibody tests – this test remains positive after treatment, so it cannot differentiate between current and past infection

Non-specific tests include venereal disease research laboratory (VDLR) – this has high sensitivity in secondary syphilis and levels decline after treatment

Management

1st line IM benzathine penicillin – 2nd line is doxycycline

Genital Herpes

This is an ulcerating condition which is caused by the herpes simplex virus.

It is usually caused by HSV-2 but can also be caused by HSV-1.

Onset of symptoms occurs around 4 days after exposure. This leads to a primary infection which can be severe and then further outbreaks, which are usually milder.

Symptoms

Males – multiple blisters that form ulcers on glans, shaft of penis, thighs or anus

Females – multiple blisters that form ulcers on vulva, buttocks, clitoris or anus

Fever and headache with general malaise

Key tests

Nucleic acid amplification testing of swab

Management

Antiviral therapy, e.g., oral acyclovir

If pregnant > 28 weeks’ gestation, consider elective caesarean section

Lymphogranuloma Venereum (LGV)

This is an invasion of the inguinal lymph system, causing granulomatous inflammation.

It is a complication of the STI Chlamydia trachomatis.

It leads to ulceration and a tender inguinal canal with swollen inguinal lymph nodes.

It heals with fibrosis but can involve perianal structures causing rectal strictures.

Symptoms

Primary stage

Painless genital ulcer at contact site 3–12 days after infection, healing in a few days

Secondary stage

Bilateral or unilateral swollen, painful inguinal lymph nodes 10–30 days later

If route was anal, can develop proctitis symptoms (anal pain, tenesmus, diarrhoea and abdominal cramps

Key tests

Serological testing

Management

Antibiotic treatment for chlamydia, e.g., doxycycline

Chancroid

This is an STD which is caused by the bacteria Haemophilus ducreyi.

It is rare in UK, but a very common cause of genital ulceration in the world.

It causes local symptoms and there are usually no systemic signs.

Symptoms

Painful ulcers with sharply defined irregular saucer-shaped borders

Painful unilateral inguinal lymphadenopathy

In females can cause dysuria and dyspareunia

Management

1st line is macrolide antibiotics (Azithromycin, erythromycin)

Conditions affecting women

Bacterial Vaginosis

This condition is due to an overgrowth of bacteria in the vaginal canal.

The vagina is normally dominated by Lactobacillus, but overgrowth of the anaerobic bacteria Gardnerella vaginalis creates a biofilm.

This allows other opportunistic bacteria to thrive. Colonisation of anaerobic bacteria means aerobic Lactobacilli stop making lactic acid, raising the pH of the discharge.

Symptoms

It is asymptomatic in about half of women and usually not painful

“Fishy” odour which smells bad and is white or grey in colour

Diagnosis

This is done using a vaginal swab. Looking for at least 3 features:

i) pH > 4.5

ii) Thin, white discharge

iii) Clue cells seen on microscopy

iv) Positive whiff test –> this is when adding potassium hydroxide gives a fishy odour

Management

1st line is oral metronidazole for 5-7 days

Trichomonas Vaginalis

This is a protozoan parasite which causes the STI trichomoniasis, spread via skin-to-skin contact.

Symptoms

Offensive smelling vaginal discharge which is yellow/green in colour

Vulvovaginitis (itching, burning, pain) with a strawberry cervix

It is usually asymptomatic in men, but can cause urethritis

Key tests 

Vaginal smear and wet mount microscopy shows the trophozoites

pH of vaginal discharge > 4.5

Management

1st line is oral metronidazole for 5-7 days

Candidiasis

This is called vaginal thrush and it is usually self-diagnosed and managed.

It is due to growth of the yeast Candida which colonises the vagina causing irritation.

It is not entirely regarded as an STI as there is no infectious risk to the partner.

It is associated with increased age, immunosuppression, pregnancy and diabetes.

Risk factors

Age

Immunosuppression

Pregnancy

Diabetes

Symptoms

Itchy vagina with dyspareunia (painful intercourse)

“Cottage-cheese” discharge which does not smell offensive

Symptoms can worsen just before a woman’s period

Key tests

Usually diagnosed clinically, but if doubt take vaginal swab

Management

If moderate, intravaginal antifungal (e.g., clotrimazole 500 mg pessary)

If more severe, oral fluconazole 150 mg single dose can be give