Sexually Transmitted infections

Question 1

Neisseria Gonorrhoea microbiology

Answer 1

• Obligate intracellular bacterium

- Gram negative diplococcus

Question 2

Chlamydia Trachomatis Microbiology

Answer 2

• Gram negative Obligate intracellular pathogen
• Can’t be cultured on agar, as requires tissue to grow on
• Diagnosis: Nucleic Acid Amplification testing (NAAT) is the gold standard

Question 3

Chlamydia infection

Answer 3

• associated with younger age
• 10% of those under 25 are infected
• Serovars A, B and C cause Trachoma, an eye infection that can lead to blindness
• Serovars D - K cause genital chlamydia infection and ophthalmia neonatorum

Question 4

Complications of Chlamydia Infection

Answer 4

• Pelvic inflammatory disease and chronic pelvic pain
• Can lead to tubal factor infertility
• increased risk of ectopic pregnancy if Fallopian tubes are scarred
• increased risk of endometriosis
• Epididymitis
• Reiter’s syndrome
• Conjunctivitis
• Opthalmia neonatorum

Question 5

Treatment of Chlamydia

Answer 5

If uncomplicated, treatment is with Azithromycin (1g/4 capsules) or Doxycycline (100mg BD for 7 days)

Question 6

Side effects of Chlamydia treatment

Answer 6

Treatment with azithromycin or doxycycline can lead to N&V and photosensitivity. It is also contraindicated in Pregnancy, as it causes disturbance to bone growth and tooth discolouration.

Question 7

Lympho-Granuloma Venereum (LGV)

Answer 7

• lymphatic infection with chlamydia trachomatis
• Chlamydia trachomatis is a gram negative obligate intracellular pathogen
• Caused by Serovars L1, L2 and L3
• endemic in the developing world
• common in MSM in developed world

Question 8

Lympho-granuloma Venereum infection: early, middle and late stages

Answer 8

• Early LGV infection - the first stage is a painless, non-infuriated genital ulcer, balanitis, proctitis or cervicitis (lasting 3-12 days)
• Next, the patient may develop inguinal Buboes, which are painful and generally unilateral. Proctocolitis, hyperplasia of lymphoid tissue Fever, malaise and more rarely hepatitis, meningo-encephalitis or pneumonia is. This stage lasts between 2-25 weeks
• Late LGV - inguinal lymphadenopathy, abscess formation, genital elephantiasis, genital ulcers, frozen pelvis, strictures, fissures and lympherroids

During a current LGV outbreak, there may be rectal symptoms such as pain, tenesmus, bleeding and mucus discharge. On examination there will be visible proctitis.

Question 9

Lymphogranuloma Venereum Diagnosis

Answer 9

• NAAT is used, despite being unliscensed
• Send to lab for confirmation of Chlamydia trachomatis using real time PCR on 2 platforms
• Genotypic identification of the L1, L2 and L3 serovars

Question 10

Lymphogranuloma Venereum Treatment

Answer 10

• Doxycycline - 100mg BD for 21 days
• other Tetracyclines may alternatively be given
• Erythromycin 500mg QDS for 21 days or azithromycin 1g weekly for 3 weeks

Question 11

Syphilis Microbiology

Answer 11

• Caused by Treponema Pallidum
• Treponema Pallidum is a gram negative Spirochaete
• Treponemes in primary lesions may be seen by dark-ground microscopy
• Can be detected using multiplex real-time PCR

Question 12

Diagnosis and detection of Syphilis

Answer 12

• VDRL (venereal disease research lab test) - detects non-specific lipoidal antibodies, may get false positives in other conditions
• RPR (rapid plasma reagin test) - modified VDRL test, positive result indicates syphilis. RPR titre falls in response to treatment so can be used to monitor treatment response
• Direct Treponemal tests: involves detecting antibodies against specific antigens from treponema pallidum. Various different types: Enzyme Immunoassay (EIA), T. pallidum Haemagglutination test (TPHA), Fluorescent treponemal antibody (FTA). These tests are more specific and remain positive despite effective treatment

Question 13

Primary Syphilis

Answer 13

• Syphilis begins with an indurated, painless genital ulcer
• usually a solitary ulcer, well demarquated
• Ulcer appears 1-12 weeks following Syphilis transmission
• clean base and serous exudate
• regional lymphadenopathy
• Syphilitic ulcer may persist for 4-6 weeks (can be referred to as a Chancre)

Question 14

Secondary Syphilis

Answer 14

CAN MANIFEST IN DIFFERENT WAYS, GEBERALLY INVOLVES THE SKIN, MUCOUS MEMBRANES, AND LYMPH NODES.
• generally 4-10 weeks after primary infection
• systemic bacteraemia causing low grade fever and malaise
• symmetrical and non-pruritic maculopapular rash on the back, trunk, arms, legs, palms, soles and face
• mucosal lesions, uveitis, choroidoretinitis, alopecia, snail track oral ulcers, condyloma acuminate (genital ulcers)
• may be neurological involvement - aseptic meningitis, cranial nerve palsy, optic neuritis or acute nerve deafness

Question 15

Latent Syphilis

Answer 15

When there is serological evidence of infection, but no symptoms of the disease.

Question 16

Tertiary Syphilis

Answer 16

• Gumma/granuloma/Gummatous Syphilis - rare, occur 2-40 years later affecting the skin, bone and mucosa (15%)
• Neurosyphilis (6.5%) - 2-30 years later. Most common in HIV+ patients. Meningovascular effects and general paresis of the insane. Tabes dorsalis and Gemma. Spirochaetes in CSF. Small vessel vasculitis. Argyll-Robertson pupil (accommodates but doesn’t react)
• Cardiovascular Syphilis (10%) - occurs 10-30 years later. Syphilitic aortitis with +++ Spirochaetes and inflammation

Question 17

Argyll-Robertson Pupil

Answer 17

Also known as prostitute’s pupil. This is a pupil that accommodates but does not react to light. Associated with neurosyphilis.