Sexually Transmitted Bacterial Infections Flashcards
What causes gonorrhoea?
Gram negative diplococcus, Neisseria gonorrhoea.
Acute infection can occur on any mucous membrane surface, typically genitourinary but also rectum and pharynx. The incubation period of gonorrhoea is 2-5 days
What are the features of gonorrhoea infection?
Males: urethral discharge, dysuria
Females: cervicitis e.g. leading to vaginal discharge
Rectal and pharyngeal infection is usually asymptomatic
Why is immunisation not possible in gonorrhoea?
Immunisation is not possible and reinfection is common due to antigen variation of type IV pili (proteins which adhere to surfaces) and Opa proteins (surface proteins which bind to receptors on immune cells).
What are the local complications of gonorrhoea?
Urethral strictures, epididymitis and salpingitis (hence may lead to infertility). Disseminated infection may occur (disseminated gonococcal infection)
How is gonorrhoea managed?
Previously the first-line treatment was IM ceftriaxone + oral azithromycin.
The new first-line treatment is a single dose of IM ceftriaxone 1g (i.e. no longer add azithromycin). If sensitivities are known (and the organism is sensitive to ciprofloxacin) then a single dose of oral ciprofloxacin 500mg should be given.
If ceftriaxone is refused (e.g. needle-phobic) then oral cefixime 400mg (single dose) + oral azithromycin 2g (single dose) should be used.
In penicillin allergic patients, single azithromycin should be used.
What is disseminated gonococcal infection?
Disseminated gonococcal infection (DGI) and gonococcal arthritis may also occur, with gonococcal infection being the most common cause of septic arthritis in young adults. The pathophysiology of DGI is not fully understood but is thought to be due to haematogenous spread from mucosal infection (e.g. Asymptomatic genital infection). Initially there may be a classic triad of symptoms: tenosynovitis, migratory polyarthritis and dermatitis. Later complications include septic arthritis, endocarditis and perihepatitis (Fitz-Hugh-Curtis syndrome)
What is non-gonococcal uretheritis?
Non-gonococcal urethritis (NGU, sometimes referred to as non-specific urethritis) is a term used to describe the presence of urethritis when a gonococcal bacteria are not identifiable or the initial swab. A typical case would be a male who presented to a GUM clinic with a purulent urethral discharge and dysuria. A swab would be taken in clinic, microscopy performed which showed neutrophils but no Gram negative diplococci (i.e. no evidence of gonorrhoea). Clearly this patient requires immediate treatment prior to waiting for the Chlamydia test to come back and hence an initial diagnosis of NGU is made.
What causes non gonococcal urethritis?
Chlamydia trachomatis - most common cause
Mycoplasma genitalium - thought to cause more symptoms than Chlamydia
How is non gonococcal urethritis managed?
Contact tracing
BNF and British Association for Sexual Health and HIV (BASHH) both recommend either oral azithromycin or doxycycline
What are the features of chlamydial infection?
Asymptomatic in around 70% of women and 50% of men
Women: cervicitis (discharge, bleeding), dysuria
Men: urethral discharge, dysuria
What are the potential complications of chlamydia?
Epididymitis
Pelvic inflammatory disease
Endometritis
Increased incidence of ectopic pregnancies
Infertility
Reactive arthritis
Perihepatitis (Fitz-Hugh-Curtis syndrome)
How should suspected chlamydia cases be investigated?
Traditional cell culture is no longer widely used
Nuclear acid amplification tests (NAATs) are now the investigation of choice
Urine (first void urine sample), vulvovaginal swab or cervical swab may be tested using the NAAT technique
Women: the vulvovaginal swab is first-line
Men: the urine test is first-line
Chlamydia testing should be carried out two weeks after a possible exposure
How is chlamydia managed?
Doxycycline (7 day course) if first-line
- this is now preferred to azithromycin due to concerns about Mycoplasma genitalium. This infection is often coexistant in patients with Chlamydia and there is evidence of rising levels of macrolide resistance, hence why doxycycline is preferred
- if doxycycline is contraindicated / not tolerated then either azithromycin (1g od for one day, then 500mg od for two days) should be used
How should chlamydia in pregnancy be managed?
If pregnant then azithromycin, erythromycin or amoxicillin may be used. The SIGN guidelines suggest azithromycin 1g stat is the drug of choice ‘following discussion of the balance of benefits and risks with the patient
Over what time frame does partner notification for chlamydia need to take?
For men with urethral symptoms: all contacts since, and in the four weeks prior to, the onset of symptoms
For women and asymptomatic men all partners from the last six months or the most recent sexual partner should be contacted
Contacts of confirmed Chlamydia cases should be offered treatment prior to the results of their investigations being known (treat then test)
