STIs Flashcards
STI syndromes
Genital discharge
Genital warts/ulcers
Pelvic pain
Sexually transmitted and blood-borne viruses
Risk factors
Young age No barrier contraception Non-regular sexual relationships Men who have sex with men IV drug use African origin Social deprivation Sex workers Poor access to advice and treatment of STIs
Determinants of risky sexual behaviour
Individual factors - low self esteem, lack of skills and knowledge of risks of unsafe sex
External influences - peer pressure, attitudes and prejudices of society
Service provision - accessibility of sexual health services and/or lack of resources such as condoms
NAATs lab investigation
Nucleic acid amplification testing
Rely on detection of DNA
Used for Chlamydia and N.gonnorhoea
PCR can also be used for herpes
Microscopy, culture and sensitivity lab investigation
For N.gonorrhoeae, candida, bacterial vaginosis (BV), trichomonas vaginalis
Charcoal swab the medium used for gonoccoi (but also useful for transporting other organisms)
Blood test lab investigation
Syphilis, HIV, hepatitis
Chlamydia trachomatis - symptoms and complications
Obligate, intracellular, Gram -ve
Symptoms include discharge, tenderness, infertility in women, Relter’s syndrome (arthritis, cervicitis, urethritis, conjunctivitis), proctitis (inflamm of inner rectum), pharyngitis, perihepatitis (upper abdom pain)
Complicatios include PID (if symptomatic then infertility, ectopic preg, chronic pelvic pain, sexually acquired reactive arthritis, epididymo-orchitis, peri-hepatitis
Neonatal chlamydia
Manifests as conjuctivitis 5-12 days after birth or pneumonia 1-3 months
treat with oral erythromycin
Chlamydia investigations and treatment
Women - VVS swab taken
Men - first catch urine (FCU)
Extra genital sites - rectal/pharyngeal
Treatment - doxy 100mg bd for 7 days
Avoid sexual contact for duration of tx, partner notification
LGV
Lymphogranuloma venerum
Caused by one of three invasive serovars of chlamydia trachomatis
Presents as solitary genital lesion, proctitis, lymphadanopathy
Tx - doxy
Neisseria gonnorrhoeae bacteria
Gram -ve
Intracellular diplococcus
Humans only host
Infects epithelial cells of mucous membrane of GU tract or rectum
Development of localised infection with pus production
Possible asymptomatic carriage in women
Gonorrhoea symptoms
Penile urethral infection (90% symptomatic), discharge
Female urethral infection - dysuria +/- frequency
Endocervical infection - 50% increased/altered vaginal discharge, 25% lower abdom pain, occasionally inter-menstrual bleeding
Rectal - mostly asymptomatic but can present with anal discharge/pain/discomfort
Pharyngeal - mostly asymptomatic but can present with sore throat
Gonorrhoea lab diagnosis
Light microscopy of gram-stained genital specimens to look for gram -ve diplococci
NAAT - can use urine or swabs
PMN in urethral pus
men - first pass urine
women - Vulvo-vaginal swab
MSM - rectal and pharyngeal swabs as routine
Gonorrhoea tx
One of following:
Ceftriaxone 1g IM
Cipro 500mg orally
Most strains respond to ceftriaxone
Doxy also given to pts who have concomitant chlamydial infection
Partner notification - all partners within preceding two weeks
Partner tx - if >14d after exposure test and tx if +ve, if <14d then clinical risk assessment +/- abx
Test of cure - NAAT if asymptomatic
Bacterial vaginosis
Most common cause of abnormal vaginal discharge in women of child bearing age
Overgrowth of lactobacilli
RF’s - black ethnicity, receptive cunnilingus
Presentation - offensive fishy odour without itch/irritation
Diagnosis - microscopy
Tx - metronidazole
Thrush/candida albicans
Acute dermatitis of vulva/vagina caused by invasion of commensal yeasts
Presents as itch, vulval pain, superficial dyspareunia, curd like white vaginal discharge
Diagnosis is either clinical or microscopy
Tx is topical clotrimazole, beware use with condoms
Treponema pallidum/syphilis
Primary - hard genital or oral ulcer at site of infection after about 3 weeks (asymptomatic for up to 24 weeks)
Secondary - red maculopapular rash anywhere plus pale moist papules in urogenital region and mouth
Tertiary - degeneration of nervous system, aneurysms and granulomatous lesions in liver, skin and bones in about 40% of patients
Congenital syphilis
Placental transfer after 10-15 weeks of pregnancy
Infection can cause death or spontaneous abortion of foetus
Survivors develop secondary syphilis symptoms
Syphilis diagnosis
From lesions or infected lymph nodes in early syphilis
Dark field microscopy
Direct fluorescent antibody (DFA) test
NAAT
EIA - can be for IgM for early infection or IgG - the latter becomes +ve at 5w or both
Syphilis tx
Benzathine penicillin Im single dose if early
If late then IM weekly for three weeks
Neurosyphilis - procaine penicillin IM olus probenecid or benpen
HPV
Induces hyperplastic epithelial lesions
Types exhibit tissue/cell specificity
1-6 month incubation period
Types have varying potential to cause malignancy - cervical carcinoma, urogenital warts, laryngeal papillomas, common/flat and plantar warts
Virus can be seen on colonoscopy after staining
Tx with podophyllum, cryo, laser and surgery
HPV vaccine
Two killed vaccines available - Cervarix and Gardasil
Given to girls aged 12-13 to immunise them before become sexually active
Herpes simplex virus
HSV type 1 - affects oral region and causes cold sores
HSV type 2 - associated with genital infection (penis, anus, vagina)
However both can infect mouth and/or genitals due to oral sex or autoinoculation
Commonly asymptomatic but still shedding virus and infectious
Genital herpes
Transmission occurs easily by sexual contact or during birth
Neonatal infection may result in disseminated infection often involving CNS
Genital herpes - primary infection or recurrence
Primary prevention -febrile flu like prodrome, tingling neuropathic pain in genital area, extensive bilateral crops of painful blisters, tender lymph nodes, local oedema, discharge, dysuria. Tx with saline bathing, local anasethetics and 5d course of aciclovir
recurrence - latent following first infection, periodic reactivation. Episodes shorter but quite often get recurrence after first one
HSV diagnosis
Clinical appearance
Viral culture
DNA detection using NAAT of a swab from base of ulcer
May take up to 12w to become antibody positive after primary infection
