What are the key symptoms presenting with STI?
- urethral, vaginal discharge
- lower abdo pain
- genital lumps, ulceration
- genital itching
- rectal symptoms
What are the four ‘core’ STIs tested for at sexual health clinics, and how are they tested for in men and women?
- Chlamydia trachomatis (CT)
- Neisseria gonorrhoeae (GC; gonococcus)
- HIV
- Syphilis
- GC/CT tested for by vulvovaginal swab (VVS) in women, and by first void urine (FVU) in men.
- consider throat and rectum swabs in MSM
- high vaginal swab (HVS, Amies swab) in recurrent/persistent discharge, postpartum or post gynae surgery, PID etc.
- HIV and syphilis via serology
Describe the swab findings in a positive case of GC infection.
- > 5 polymorphs per high powered field indicates urethritis
- look for gonococcal cells (these are purple gonococci within cells)
- NB CT cannot be seen on gram stain
Name the three categories of serovar seen in CT and which infection types they may cause.
- A-B: ocular infection
- D-K: urethritis, epididymo-orchitis, neonatal pneumonia and conjunctivitis
- L1-3: LGV (lymphogranuloma venereum), mainly MSM with rectal symptoms
Name the clinical features of CT.
- milky urethral discharge, irregular bleeding, abdominal pain, dysuria
- inflammation of urethra, cervix, epididymis, rectum
- [neonatal pnuemonia, conjunctivitis]
What is Fitz Hugh-Curtis Syndrome?
A very rare presentation of CT, with perihepatitis and piano-string adhesions
Describe the management of CT.
- doxycycline 100mg BD/wk
- azithromycin 1g stat + 500mg OD/2days; this is second line and should only be used when tetracyclines genuinely cannot be taken (e.g., during pregnancy) due to antibiotic resistance
What are the complications of CT?
- ectopic pregnancy
- PID (manage with ceftriaxone, doxycycline, metronidazole)
- reactive arthritis
- reinfection (1/5)
Describe the symptoms and management of NG.
- men: anterior urethritis, mucopurulent discharge, dysuria
- female: vaginal discharge, dysuria, PCB/IMB, lower abo pain
- rarer: proctitis, sepsis/DGI, tenosynovitis, arthritis, erythematous skin
- 1st line ceftriaxone 1g IM stat
- 2nd line ceftaime 400mg PO + azithromycin 2g PO (if infection C/I / rejected)
- test of cure in all patients 2 weeks following treatment
What are the complications of GC?
- Bartholin abscess
- ascending infection (endometritis, hydrosalpinx, PID)
- abscess (periurethral, rectal)
- infertility, ectopics
What are the most common causes of non-gonococcal urethritis (NGU)?
CT, mycoplasma genitalium, ureaplasma urealyticum, TV, HSV 1/2, adenoviruses
What is the wider differential diagnosis for genital ulceration?
vIndIcATe
- infectious (HSV, VZV, EBV, HIV)
- iatrogenic (drug eruption, SJS)
- autoimmune (Crohn’s, Behcet’s, lichen sclerosus)
- trauma (self-harm, artefacta)
Describe the timeline of HSV infections.
- primary: virus ascends peripheral sensory nerves to DRG, establishing latency.
- symptoms: ulcers, inguinal lymphadenopathy, viraemia, dysuria, vulval pain
- non-primary genital infection: those with previous HSV1/2 who acquire the other type.
- cross-protection from other type means a milder illness
- recurrent infection: 4x more common in HSV2 than 1
- tingling, itching, pain, unilateral ulcer, can be asymptomatic
- usually resolves 5-7days, although all episodes potentially infectious
Describe the management of HSV-caused genital ulceration.
- primary infection: saltwater bathing, topical anaesthetic (5% lidocaine), and acyclovir (400mg TDS 6/7 days).
- avoid sharing towels, etc. to prevent autoinoculation
- suppressive therapy offered with >6 recurrences/yr. This is acyclovir 400mg OD
Describe the natural history of syphilis.
- a chronic systemic disease caused by Treponema pallidum, a motile spirochete
- early infection [primary, secondary, early latent <2yr], and late non-infectious [late latent >2yr, tertiary]
- incubation 9-90 days with primary papule at site of inoculation which ulcerates to form a chancre
- secondary: widespread rash on palms/soles, anterior uveitis, condylomata lata (highly infectious plaques)
- tertiary: gummatous syphilis. can affect cardiovascular and neurological systems
Describe the investigations used for syphilis.
- cannot be cultured
- dark field microscopy, PCR, or serology (IgM/IgG ELISA)
- non-treponemal tests: VDRL, RPR
- treponemal tests: TPPA, ELISA, INNO-LIA, FTS antibodies
Describe the management of syphilis.
- single dose of 2.4 MU benzthine penicillin G IM stat
- doxycycline 100mg BD 2/52
- late syphilis: penicillin G IM weekly for 3 wk
- followup until RPR -ve or serofast. Titres should decrease fourfold by 3-6m
Which HPV subtypes are covered by the quadrivalent vaccine, and what pathologies do these cause?
- HPV 6/11: viral warts
- HPV 16/18: oncogenic
Describe the pathology of HPV infection and the main management options.
- warts appear at sites of trauma during sex (prepuce/glans, fourchette, vulva, perineum)
- non-hair-bearing skin: soft and non-keratinised
- hair-bearing skin: firm and keratinised
- topical podophyllotoxin, imiquimod, ablation (cryotherapy, electrocautery)
Name the partner notification (PN) periods for CT, GC, NGU, TV, PID, HIV, and syphilis.
- CT: male urethral 4w, others 6m
- GC: half of CT (2w/3m)
- NGU/TV: 4w
- PID: 6m
- HIV: 4w before last negative result, or 4w before most likely infection
- syphilis: primary 90 days, secondary 2yr
For which sexual infections is partner notification (PN) not required?
- warts, herpes
- thrush
- bacterial vaginosis
Describe the pathology of most cases of bacterial vaginosis (BV).
A lack of lactobacilli allows overgrowth of pathogenic bacteria (including Gardnerella vaginalis, anaerobes, mycoplasmas, and Mobiluncus spp.)
An increased pH can lead to prolonged/heavy periods
Describe the clinical features and management of BV.
- increased vaginal discharge, offensive fishy odour, creamy-white homogenous discharge which may be frothy
- amine production causes offensive odour and froth
- metronidazole 400mg BD 5-7/7
- alternatives: intravaginal metronidazole, intravaginal clindamycin
Name the key viral proteins expressed on the HIV particle.
- p10 (protease - processes viral genome RNA)
- p17, p24, gp120 (transcribes viral mRNA)
- p32 (integrase - integrates viral DNA into CD4 cells)
- gp41 - binds CD4 cells, inc. CCR5 receptors
Describe the main types of HIV, and how their epidemiology varies.
- HIV-1: accounts for most cases worldwide. subgroups include
- M (major, 98%)
- N (new)
- O (outlier)
- P (single patient in Cameroon)
- HIV-2: localised mainly to sub-Saharan Africa
Describe the viral lifecycle of HIV.
- binding (gp41)
- fusion
- reverse transcription
- integration (p32)
- replication
- transcription (p10, gp160, p24, p17)
- viral budding
Describe the changes HIV infection causes on CD4 and CD8 cells.
- decreasing circulating CD4 cells and proliferation
- increased proliferation of CD8, but decreased activation (dysregulated cytokines)
- reduced cross-switching of antibodies and subsequent affinity
There are three main stages of HIV infection. Name these and describe how CD4 cell count and viral RNA copies change during these times.
- acute HIV syndrome: rapid reduction of CD4, rapid increase in viral RNA over weeks (0-9wk)
- clinical latency: reduction in viral load and increased number of CD4 cells; these gradually increase/decrease respectively over years
- AIDS: viral load rapidly increases. CD4 count rapidly decreases.
Describe the clinical features of the acute HIV syndrome (stage 1/3).
fever, maculopapular rash, myalgia, pharyngitis, aseptic meningitis, headache
very high risk of transmission
Describe the clinical features of clinically latent HIV infection (stage 2/3).
- neuro: distal sensory polyneuropathy, mononeuritis multiplex, vascular myopathy, aseptic meningitis, GBS, neurosyphilis
- CVS: dec. HDL, increased IHD, cardiomyopathy, CHF, and myocarditis
- GI: weight loss, diarrhoea, encephalopathy, hypochlorrhydria
- endocrine: reduced testosterone, abnormal adrenal function
- renal: HIVAN, nephrotic syndrome
- haem: lymphopenia, anaemia, neutropenia, isolated thrombocytopaenia
Name the main AIDS-defining syndromes (stage 3/3).
- pulmonary (pneumocystis jiroveci, TB)
- neurological (toxoplasma gondii, PML by JC virus
- CMV (retinitis, colitis, and/or encephalopathy)
- viral (VZV, HSV; more extensive and recurrent)
- neoplasia: HHV8 (Kaposi sarcoma), EBV (non-Hodgkin, Burkitt lymphoma)
Name the main methods of transmission of HIV.
- sex (raised in MSM, trauma, ulceration, concurrent STI)
- parenteral (PWIDs, contaminated blood and blood products)
- mother-to-child (transplacental, perinatal, breastfeeding)
Who do we screen for HIV?
- universal, where prevalence >0.2% (NHS Lothian)
- GUM clinics, antenatal services, TOP services, drug dependency programmes, care for TB/HBV/HCV/lymphoma
- high-risk: those with STI, partners of those with HIV, MSM and their F contacts, PWIDs, those from countries of high prevalence
- those with indicator conditions
Name the drug classes used in the treatment of HIV.
- NRTIs (nucleoside reverse transcriptase inhibitors)
- NNRTIs (non-NRTIs)
- integrase inhibitors
- protease inhibitors
- coreceptor (CCR5) inhibitors
- fusion inhibitors (very expensive, S/C, last option)
- [in development: capsid, monoclonal antibodies, maturation-based drugs]
Describe the makeup and purpose of HAART.
- combination of 3 drugs, from which at least 2 are classes to which the virus is susceptible.
- 2 NRTIs + 1 other agent
- reduce viral load, restore immunocompetence, reduce morbidity, mortality, and transmission.
Describe and give examples of primary and secondary prevention of HIV.
- primary prevention: acquiring HIV. condoms, regular tests, behaviour change, PEP/PrEP, PMTCT, circumcision, needle exchange
- secondary prevention: onward transmission. condoms, regular tests, behaviour change, disclosure, PMTCT, needle exchange
What are the criteria for PrEP?
- MSM condomless anal sex, 2+ partners in the last year, sex likely in the next 3m
- rectal bacterial STI in last year
- partner of someone with HIV who does not have suppressed viral load.
When is PEP initiated?
<72h after possible exposure to HIV (occupational, sexual). Taken for 4 weeks.
Describe PMTCT.
- prevention of mother to child transmission
- achieved with HAART during pregnancy
- vaginal delivery undertaken with an undetectable viral load
- C/S done with a detectable viral load.
