Sexually Transmitted Infections - Chlamydia, Gonorrhoea + Syphilis Flashcards
What is the most common STI?
Chlamydia
Is chlamydia more common in males or females?
Females - 15-25 YO
Is gonorrhoea more common in males or females?
Males
What is the bacteria causing chlamydia?
Chlamydia trachomatis:
- Gram-NEGATIVE bacterium
What is the bacteria causing gonorrhoea?
Neisseria gonorrhoea:
- Gram-NEGATIVE diplococcus bacterium
What are site of occurrence of chlamydia & gonorrhoea in adults?
- Urethra
- Endocervical canal
- Rectum
- Pharynx
- Conjunctiva
What are site of occurrence of chlamydia & gonorrhoea in neonates?
- Conjunctiva
- Atypical pneumonia also in neonatal Chlamydia
Does chlamydia infect the vagina?
No.
Chlamydia and gonorrhoea cannot infect squamous epithelium.
What is the incubation period for chlamydia and gonorrhoea?
Chlamydia = 1-3 weeks
Gonorrhoea = 10 days for women; 1-5 days in men
What does gonorrhoea look like on a gram stain?
Gram negative.
Diplococci.
In the cytoplasm of polymorphs.
What is the primary site of infection for chlamydia + gonorrhoea in males?
Urethra
What is the primary site of infection for chlamydia + gonorrhoea in females?
Cervix
Describe the clinical presentation of chlamydia + gonorrhoea in females.
Asymptomatic.
Change in vaginal discharge.
Menstrual irregularity.
Dysuria.
What are the 2 complications of chlamydia in males?
Epididymo-orchitis and reactive arthritis
Give 3 complications of chlamydia + gonorrhoea in females.
- Pelvic inflammatory disease (PID)
- Neonatal transmission
- Fitz-Hugh-Curtis Syndrome
- Peri-hepatitis but no decline in liver function
Diagnosis of chlamydia.
Nucleic Acid Amplification Tests (NAATs):
- High specificity and sensitivity - but negative test DOES NOT EQUAL not infected
- Females:
- Self collected vaginal swab - better since more material collected
- Endocervical swab
- First void urine - lower sensitivity
- Male - first void urine
Diagnosis of gonorrhoea.
- Nucleic acid amplification testing (NAAT):
- Used to detect the RNA or DNA of gonorrhoea. - Near patient tests:
- Microscopy of gram stained smears of genital secretions - looking for GRAM-NEGATIVE DIPLOCOCCI
- Male: sample from urethra
- Female: sample from endocervix - Culture on selective medium to confirm
- Antibiotic sensitivity testing:
- A standard charcoal endocervical swab should be taken for microscopy, culture and antibiotic sensitivities before initiating antibiotics.
- This is particularly important, given the high rates of antibiotic resistance.
Management of chlamydia.
- Partner management
- Test for other STIs
- ORAL AZITHROMYCIN STAT (convenient - just 1 dose) or ORAL
DOXYCYCLINE for 7 days (less convenient, but more effective)
- Pregnant:
- ERYTHROMYCIN for 14 days or AZITHROMYCIN STAT
Management for gonorrhoea.
- Partner notification!
- Test for other STIs
- Continuous surveillance of antibiotic sensitivity
- Single dose treatment is preferred:
* IM CEFTRIAXONE with AZITHROMYCIN STAT
What organism causes syphilis?
Treponema pallidum
What are the features of primary syphilis?
Chancre (painless ulcer)
Macule - papule - non tender solitary ulcer
What are the features of secondary syphilis?
Maculopapular rash
Condylomata lata (grey wart-like lesions around the genitals and anus)
Low-grade fever
Lymphadenopathy
Alopecia (localised hair loss)
Oral lesions
What are the features of tertiary syphilis?
Key features to be aware of are:
Gummatous lesions (gummas are granulomatous lesions that can affect the skin, organs and bones)
Aortic aneurysms
Neurosyphilis
What are the features of neurosyphilis?
Neurosyphilis can occur at any stage if the infection reaches the central nervous system, and present with symptoms of:
Headache
Altered behaviour
Dementia
Tabes dorsalis (demyelination affecting the spinal cord posterior columns)
Ocular syphilis (affecting the eyes)
Paralysis
Sensory impairment
What is a Argyll-Robertson pupil?
Argyll-Robertson pupil is a specific finding in neurosyphilis.
It is a constricted pupil that accommodates when focusing on a near object but does not react to light.
They are often irregularly shaped.
It is commonly called a “prostitutes pupil” due to the relation to neurosyphilis and because “it accommodates but does not react“.
Management of syphilis.
- Full screening for other STIs
- Advice about avoiding sexual activity until treated
- Contact tracing
- Prevention of future infections
- A single deep IM dose of benzathine benzylpenicillin (penicillin)
What is the most common cause of epidydimitis?
- Gonorrhoea in young
- E coli over 35
