STIs 2 Flashcards
Obligate gram -ve spirochaete. Found in HIV +ve patients
Often co-infected with HCV or another STI
Rising in the UK
Treponema pallidum - Syphilis
Gold standard diagnosis of syphilis
Treponemes in primary lesions by dark-ground microscopy
Can be detected by real time PCR
Detection of Ab is diagnostic method of choice
Non-treponemal test for syphilis
Detect non-specific Ab
VDRL test slide - detect lipodal Ab on host and treponemal cells
Reagents contain cardiolipin, lecithin and cholesterol - biological false positives
RPR is modified VDRL test
Positive is indicative of treponemal infection
Useful in primary syphilis
Titre falls in response to treatment therefore can be used to monitor response
Treponemal test for syphilis
Detect Abs against specific antigens from T pallidum
Eg - Enzyme immunoassay, fluorescenet treponemal antibody, T pallidum haemagglutination test, T pallidum particle agglutination test
More specific than non-treponemal test
Remains positive for years despite treatment
Symptoms of primary syphilis
Macule - Papule - Indurated painless genital ulcer appearing 1-12 weeks following transmission Often solitary May persist 4-6 weeks (chancre) Clean base with serious exudate Regional adenopathy
Symptoms of secondary syphilis
Systemic bacteraemia
Low grade fever, malaise
Symmetrical, non-pruritic, maculo-papular rash on back, trunk, arms, legs, palms, soles, face (1-6 motnhs following infection)
Mucousal lesions, uveitis, choroidoretinitis, alopecia, ‘snail track’ oral ulcers, conyloma acuminate (genital warts)
Neurological involvement (aseptic meningitis, cranial nerve palsies, optic neuritis, acute nerve deafness)
Symptoms of Latent Syphilis
No obvious signs but serological infection (asymptomatic)
Symptoms of tertiary syphilis
Gumma (Granuloma) - Rare, 2-40 years later. Skin, bone, mucosa. Spirochaetes scanty - DTH reaction
Cardiovascular - 10-30 years later. Uncomplicated + complicated aortitis. +++spirochaetes +++inflammation
Neurosyphilis (most common in HIV +ve) - 2-30 years later. Meningovascular, general paresis of insane, Tabes dorsalis, Gumma. Spirochaetes in CSF. Small vessel vasculitis. Argyll-Robinson pupil (accommodates but does not react)
Treatment of Syphilis
Single dose IM Benzathine Penicillin
Doxycycline if allergic
Monitor RPR p 4-fold reduction to show Tx success
Jarisch-Heimer reaction - fever, headache, myalgia, somtimes exacerbation of syphilitic symptoms - Common. Develops within hours of abx and clears within 24 hours
Congenital syphilis
May occur during pregnancy or birth
Develops features over first couple of years
Hepatosplenomegaly, rash, fever, neurosyphilis, pneumonitis,
Late congenital syphilis in 40%
Tropical ulcer disease mainly in africa. Rare in UK
Gram -ve coccobacillus
Multiple ulcers, frequently painful
Diagnosis - chocolate agar, PCR
Chancroid Haemophilus ducreyi (similar to HiB)
Gram -ve bacillus
Africa, India, PNG, Australian aborginal communities
Large expanding ulcers starting as papule or nodule that breaks down. Beefy red apearance
Diagnosis - Giemsa stain of biopsy or tissue crush, Donovan bodies
Donovanosis - Granuloma inguinale
Klebsiella granulomatis
Tx - azithromycin
Other enteric pathogens that cause STIs through oral-anal content
Shigella, salmonella, Giardia (protozoan), occasionally others (Strongyloides)
Flagellated protozoan
Diagnosis - Wet prep microscopy, PCR
Asymptomatic or urethritis in men. Discharge in women. Assoc risk of HIV acquisition
Trichomoniasis
T vaginalis
Tx - Metronidazole
Abnormal vaginal flora, polymicrobial, reduction in lactobacilli. Discharge and odour
Sexually associated, not transmitted. Associated with hygiene practices
Diagnosis on microscopy of gram stain, raised pH, whiff test, clue cells
ASsoc with preterm delivery
Often recurrent
Bacterial vaginosis
Still not fully understood
