GUM - Bacterial STIs Flashcards Preview

Year 4 - SPM > GUM - Bacterial STIs > Flashcards

Flashcards in GUM - Bacterial STIs Deck (39):

What is LGV? How is it treated?

Lymphogranuloma venereum (LGV) is caused by Chlamydia trachomatis. Typically infection comprises of three stages:
- stage 1: small painless pustule which later forms an ulcer
- stage 2: painful inguinal lymphadenopathy
- stage 3: proctocolitis

LGV is treated with doxycycline.


Other than LGV, what other STIs can cause genital ulcers?

Genital herpes
Chancroid (tropical disease cause by haemophilus ducreyi)
Behcets disease
Granulome inguinale (caused by Klebsiella granulomatis)


What causes gonorrhoea? What is the incubation period?

Gonorrhoea is caused by the Gram negative diplococcus Neisseria gonorrhoeae. 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, but symptoms can take 2 weeks to develop.


What are the clinical features of gonorrhoea?

- males: urethral discharge, dysuria
- females: cervicitis e.g. leading to vaginal discharge
- rectal and pharyngeal infection is usually asymptomatic

The discharge is characteristically yellow/ green.
80% are asymptomatic.


How is the diagnosis of gonorrhoea confirmed?

Swabs of the discharge or exposed areas are taken for NAATS (nucleic acid amplification) using either orange or white tubes, but both are quite often done together.

Discharge is also cultured onto chocolate agar or selective media (VCN*) to prevent growth of other organisms.

Dry microscopy also shows the presence of puss cells (PMNS containing gram negative diplococci).

*VCN is a medium containing vancomycin, collistin and nystatin


Is immunisation possible for gonorrhoea infection?

No. 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 complications of gonorrhoea infection?

Local complications that may develop include urethral strictures, epididymitis and salpingitis (hence may lead to infertility). Disseminated infection may occur.


How is gonorrhoea treated?

The 2011 British Society for Sexual Health and HIV (BASHH) guidelines recommend ceftriaxone 500 mg intramuscularly as a single dose with azithromycin 1 g oral as a single dose. The azithromycin is thought to act synergistically with ceftriaxone and is also useful for eradicating any co-existent Chlamydia infections. This combination can be used in pregnant women as well
if ceftriaxone is refused or contraindicated other options include cefixime 400mg PO (single dose).


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 urethritis?

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 organisms most commonly cause NGU?

Causative organisms include:
- Chlamydia trachomatis - most common cause
- Mycoplasma genitalium - thought to cause more symptoms than Chlamydia


How is NGU managed?

- contact tracing
- the BNF and British Association for Sexual Health and HIV (BASHH) both recommend either oral azithromycin or doxycycline


What causes chlamydia?

Chlamydia is the most prevalent sexually transmitted infection in the UK and is caused by Chlamydia trachomatis, an obligate intracellular pathogen. Approximately 1 in 10 young women in the UK have Chlamydia. The incubation period is around 7-21 days, although it should be remembered a large percentage of cases are asymptomatic.


What are the clinical features of chlamydia?

- asymptomatic in around 70% of women and 50% of men
- women: cervicitis (discharge, bleeding), dysuria
- men: urethral discharge, dysuria
- abdominal pain


How is chlamydia investigated?

Traditional cell culture is no longer widely used.
Nuclear acid amplification tests (NAATs) are now rapidly emerging as the investigation of choice.
Urine (first void urine sample), vulvovaginal swab or cervical swab may be tested using the NAAT technique.

If a female presents with abdo pain a pregnancy test should also be performed to check for ectopic pregnancy.


What are the potential complications of chlamydia infection?

pelvic inflammatory disease (suggested by lower abdominal pain, dyspareunia, or intermenstrual bleeding)
increased incidence of ectopic pregnancies
reactive arthritis
perihepatitis (Fitz-Hugh-Curtis syndrome)


How is chlamydia treated?

Doxycycline (7 day course) or azithromycin (single dose). The 2009 SIGN guidelines suggest azithromycin should be used first-line due to potentially poor compliance with a 7 day course of doxycycline.

If pregnant then azithromycin, erythromycin or amoxicillin may be used. The SIGN guidelines suggest azithromycin 1g stat is the drug of choice.

Patients diagnosed with Chlamydia should be offered a choice of provider for initial partner notification - either trained practice nurses with support from GUM, or referral to GUM. For men with urethral symptoms: all contacts since, and in the four weeks prior to, the onset.


How should contacts of patients with known chlamydia infection be treated?

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).


How should contacts of patients with known chlamydia infection be treated?

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).


What is pelvic inflammatory disease (PID)?

Pelvic inflammatory disease (PID) is a term used to describe infection and inflammation of the female pelvic organs including the uterus, fallopian tubes, ovaries and the surrounding peritoneum. It is usually the result of ascending infection from the endocervix.


What causes PID?

Causative organisms:
- Chlamydia trachomatis - the most common cause
- Neisseria gonorrhoeae
- Mycoplasma genitalium
- Mycoplasma hominis


What are the features of PID?

lower abdominal pain
deep dyspareunia
dysuria and menstrual irregularities may occur
vaginal or cervical discharge
cervical excitation


How should PID be investigated?

Screen for chlamydia and gonorrhoea


What are the complications of PID?

infertility - the risk may be as high as 10-20% after a single episode
chronic pelvic pain
ectopic pregnancy


What are the complications of PID?

infertility - the risk may be as high as 10-20% after a single episode
chronic pelvic pain
ectopic pregnancy


What is primary syphilis?

The primary lesion or chancre develops at the site of infection, usually in the genital area. A dull red macule develops, becomes papular and then erodes to form an indurated, painless ulcer (chancre) with associated inguinal lymphadenopathy. Without treatment, the chancre will resolve within 2–6 wks to leave a thin atrophic scar. The lesion is often not visible in women, may develop on the cervix.


How long is the incubation period for syphilis?

Incubation is usually 6 weeks, with a range of 9-90 days.


What is secondary syphilis?

This occurs 6–8 wks after the development of the chancre when treponemes disseminate to produce a multisystem disease. Constitutional features such as mild fever, malaise and headache are common. Over 75% of patients present with a macu- lopapular rash on the trunk and limbs that may later involve the palms and soles. Generalised non-tender lymphadenopathy is present in >50% of patients. Mucosal lesions, known as mucous patches, may affect the genitalia, mouth, pharynx or larynx and are essentially modified papules, which become eroded. Rarely, conflu- ence produces characteristic ‘snail track ulcers’ in the mouth.


What is tertiary syphilis?

This takes a minimum of 6 years to develop. The characteristic feature is a chronic granulomatous lesion called a gumma, which may be single or multiple and can affect skin, mucosa, bone, muscles or viscera. Resolution of active disease should follow treatment, though some tissue damage may be permanent.
After several years, cardiovascular syphilis, particularly aortitis with aortic incompetence, angina and aneurysm, and neurosyphilis, with meningovascular disease, tabes dorsalis or general paralysis of the insane, may develop.


What is the rule of 6s with syphilis?

Incubation period is 6 weeks (range from 9-90 days)
Chancre takes 6 weeks to heal
6 weeks after the primary lesion has healed, secondary syphilis develops
6 weeks for secondary syphilis to resolve
66% of patients with latent infection with resolve spontaneously (no tertiary syphilis)
6 years at least to develop tertiary syphilis


What is congenital syphilis?

This is rare where antenatal serological screening is practised. Antisyphilitic treatment in pregnancy treats the fetus, if infected, as well as the mother. Treponemal infection in pregnancy may result in:
- miscarriage or still birth
- syphilitic baby (a very sick baby with hepatosplenomegaly and a bullous rash)
- a baby who develops signs of congenital syphilis (condylomata lata, oral/anal/ perineal fissures, "snuffles", lymphadenopathy, and hepatosplenomegaly)


What features do adults with congenital syphilis often display?

Hutchinson's incisors (anterior-posterior thickening with notch on narrowed cutting edge)
Mulberry molars (imperfectly formed cusps/ deficient dental enamel)
High arched palate
Maxillary hypoplasia
Rhagades (radiating scars around mouth, nose, and anus)
Sabre shins
Bossing of frontal and parietal bones


How is syphilis diagnosed?

Absolute diagnosis during the first and second stages of syphilis can be made using direct examination, under dark field microscopy, of a specimen from a primary chancre, the maculopapular rash or the condylomata lata. Darkfield microscopy reveals tiny helically shaped organisms moving like corkscrews. But direct visualisation of spirochetes only happens during active infection in primary and secondary syphilis, serological tests are also required.

There are 2 types of serologic screening test: non specific and specific.


What is a non specific treponemal test?

Infection with syphilis results in cellular damage and the release into the serum of a number of lipids, including cardiolipin and lecithin. The body produces antibodies against these antigens. Therefore, the quantity of these antibody titres can be measured. If a patients serum has these antibodies, we suspect that he/she has syphilis.

Invasion of the CSF by syphilis also stimulates an increase in these anti-lipoidal antibodies, so this test can also be performed on CSF to confirm the diagnosis of neurosyphilis. The two most common types of technique are the venereal disease research laboratory (VDRL) and the rapid plasma reagin (RPR) test.

These tests are non specific because 1% of adults without syphilis will also have these antibodies, so a positive non specific test must be confirmed with a specific treponemal test.


What is a specific treponemal test?

While the nonspecific tests look for anti-lipoidal antibodies, the specific treponemal tests look for antibodies against the spirochetes. The Indirect Immunofluorescent Tre- ponemal Antibody-Absorption (FTA-ABS) test is the most commonly used specific treponemal test. This test is performed by first mixing the patient's serum with a standardized nonpathogenic strain of Treponema, which removes (absorbs) antibodies shared by both Treponema pallidum and the nonpathogenic tre- ponemal strains (as nonpathogenic strains of Tre- ponema are part of the normal human flora). The remaining serum is then added to a slide covered with killed Treponema pallidum (as the antigen). Antibodies that are specific to this organism will subsequently bind, giving a positive result.
Since we all have antibodies to nonpathogenic strains of treponemes, the absorption part of the FTA-ABS test is necessary to cut down on the number of false positives. Only people who have antibodies specific for the pathogenic strain of treponemes will elicit a positive re- action. However, false positives can occur with other spirochetal infections, such as yaws, pinta, leptospirosis, and Lyme disease.


What would a positive VDRL/ RPR test and a positive FTA-ABS test indicate?

Active treponemal infection


What does a negative VDRL/RPR test and a positive FTA-ABS test indicate?

Successfully treated syphilis


Why should a negative VDRL/RPR test and a negative FTA-ABS test be interpreted cautously?

This result means that syphilis is unlikely although patients with syphilis infection who also have AIDS may be sero negative. Plus, patients only recently infected with syphilis may not have developed an immune response yet.


How is syphilis treated?

Alternatives: doxycycline
The Jarisch-Herxheimer reaction is sometimes seen following treatment. Fever, rash, tachycardia after first dose of antibiotic. It is thought to be due to the release of endotoxins following bacterial death and typically occurs within a few hours of treatment.

Decks in Year 4 - SPM Class (129):