STI Flashcards
what are STI caused by?
STIs can be caused by: Bacteria, viruses or parasites
Bacterial: Chlamydia, Gonorrhoea, Mycoplasma genitalium, Pelvic Inflammatory Disease (PID), Syphilis
Viral: HIV, Hepatitis B and C, Herpes, HPV
Parasitic: Lice, Trichomoniasis
what is the cause of chlamydia
symptoms
diagnosis
treatment
complications
Cause: Chlamydia trachomatis, Gram negative
Most common STI in UK – 51% of all STI cases in 2020 (49% 2019)
An intracellular infection – obligate intracellular pathogen
Attaches and invades
Becomes reticulate body
Replication of RB
Transformation of RB to EB
Cell lysis and EB release
Symptoms: Often asymptomatic. Symptoms similar to gonorrhea. Pain/burning on urination, discharge (ADD HERE)
Diagnosis: DNA testing NAAT
Treatment (since Sept 2018): 1st line doxycycline – see BASHH Guidelines and NICE guidelines (for if treated in primary care)
Due to co-infection and macrolide resistance of Mycoplasma genitalium (emerging ST pathogen – next slide) and doxycycline shown more effective rectal infection
1st line: Doxycycline 100mg BD, 7 days
2nd line: If contraindicated (e.g. in pregnancy): 1g azithromycin (SDA) then 2 days 500mg OD orally OR erythromycin 500mg BD 10-14 days/or QDS 7 days, or amoxicillin 500mg TDS 7 days. Ofloxacin 200mg BD 7 days option but also contraindicated in pregnancy
Complications: Can increase risk of contracting HIV. 50% of asymptomatic women develop PIV and infertility (requires doxycycline + metronidazole (14d) + i/m ceftriaxone)
Mycoplasma genitalium (MGEN)
causes
symptoms
diagnosis
complications
treatment
Cause: Mycoplasma genitalium (first isolated 1981 males with non-gonococcal urethritis). Small bacterium - no cell wall. Often co-infection (e.g. with Chlamydia) and linked with etiology of PID (see later)
Symptoms: Usually asymptomatic in men and women. Symptoms similar to gonorrhea and chlamydia with discharge, dysuria, urethritis (men), cervicitis (women), post-coital bleeding (women), painful inter-menstrual bleeding, lower abdominal pain (women)
Diagnosis: NAAT (FVU in men, vulvovaginal and endocervical swabs in women). Where positive, test also for macrolide resistance mutations.
Complications: Pelvic inflammatory disease (PID, see later), reactive arthritis (sexually associated, men and women), premature birth, stillbirth, miscarriage
Treatment: Macrolide resistance in UK ~40% but still responds to azithromycin in most cases. Moxifloxacin also useful but not 1st line as subsequent treatment options limited (so used if macrolide resistant or azithromycin fails)
1st line uncomplicated infection – urethritis or cervicitis (guidance Dec 2018, update Nov 2019):
100mg Doxycycline BD for 7 days then 1g azithromycin single dose then 500mg orally for further 2 days (once per day).
Alternative: moxifloxacin 400mg once daily, 14 days, also first line for complicated – such as PID (see later)
Pregnancy: 3 day course azithromycin can be used (uncomplicated cases). If resistant, options limited.
Test for cure at follow-up (TOC – Test of cure). Cases increased 196% in 2019 (5,311 cases), likely due to increased screening after guidance issued in 2018.
Gonorrhoea
causes
transmission
symptoms
diagnosis
treatment
complications
pregnancy
Causes: Neisseria gonorrhoeae – Gram negative diplococci
Transmission: vaginal/anal/oral sex and childbirth from mother to baby
Symptoms: Many women and some men can be asymptomatic. Symptoms include: dysuria, watery yellow or green vaginal discharge in women, white/yellow/green penile discharge in men, women - abdomen pain during/after sex, bleeding, men - testicular pain. Rectal infection often asymptomatic but penile urethral infection in men 90% symptoms..
Diagnosis: NAAT (sensitive), also microscopy (where sensitive enough e.g. penile urethral swab with discharge). For sensitivity testing to determine AMR, requires culture
Treatment uncomplicated genital infection (Updated January 2019): Issue is AMR– largely resistant to penicillin, tetracyclines and now to fluoroquinolones (e.g. >36% ciprofloxacin resistant). Typically in specialist care. Before Jan 2019 was Azithromycin 1g orally + i/m ceftriaxone 500mg, both as single dose.
Current 1st Line: 1g i/m Ceftriaxone (single dose). If known to be sensitive to ciprofloxacin, Ciprofloxacin 500mg orally, single dose.
Alternatives – depends on sensitivities, contraindications, patient preference.
Abstain from sex until after treatment – follow up to ensure resolution - TOC
Complications: If disseminates can be life-threatening (e.g. meningitis) – need admitting and higher dose i.m. or i.v. Ceftriaxone for a week. Spread to peritineum leads to PID. Alternatives e.g. i.v. Cefotaxime or Ciprofloxacin and i.m. Spectinomycin depending on sensitivities or contraindications.
Pregnancy: Avoid fluoroquinolones and tetracyclines. 1st line safe to use (some difference in NICE guidance with BASHH
Gonorrhoea surveillance
Surveillance: GRASP
(Gonococcal Resistance to Antimicrobials Surveillance Programme)
Surveillance of AMR and susceptibilities of infections across the UK
Annual report (see this Link to GRASP reports)
Big problem is multi-drug resistance
March 2018 case of ‘super Gonorrhoea’ (extensively drug resistant: XDR-NG) reported in UK – resistant to azithromycin and ceftriaxone. Finally cured in April using Ertapenem (i.v.). 2 more cases Oct & Dec 2018.
Pelvic Inflammatory Disease (PID)
what is it?
causes
transmission
risk factors
symptoms
diagnosis
management
outpatient regimens
inpatient regimens
complications
PID: an infection in upper part of female reproductive
System – can be ovaries, fallopian tubes, uterus and pelvis
Causes: bacteria from vagina/cervix spreading to pelvis.
Usually gonorrhea, chlamydia but can be multiple
Transmission and risk factors: STIs, multiple sexual partners. BV can increase risk
Symptoms: Can be asymptomatic. Lower abdominal pain, fever, vaginal discharge, painful urination and/or sex, irregular bleeding in menstruation. [Note: exam will reveal ]
Diagnosis: Range of exams/tests. Pelvic exam. Laparoscopy. Endocervical or vaginal pus. Positive test for gonorrhea/chlamydia/mgen (testing all three recommended). Need differential diagnosis based on combination.
Management uncomplicated genital infection: STI screening, pregnancy test
Outpatient regimens 3 first line options – Updated January 2019:
Ceftriaxone 1g i.m. single dose AND doxycycline 100mg BD orally 14 days AND metronidazole 400mg BD orally 14 days (if gonococcal)
Ofloxacin AND metronidazole, both oral 400mg BD 14 days
Moxifloxacin 400mg OD 14 days orally (if mgen +ve)
If gonorrhea, avoid (2) and (3) due to fluoroquinolone resistance. (3) Best activity against mgen, otherwise fluoroquinolones 2nd line (due to risk serious side-effects). Alternative if needed: 1g i.m. Ceftriaxone (stat) AND oral azithromycin 1g/week for 2 weeks.
Inpatient Regimens: e.g. 2g/day i.v. ceftriaxone AND 100mg BD i.v. doxycycline until 24hrs post-clinical improvement then 14 days of oral doxycycline 100mg BD and metronidazole 400mg BD
Complications: scarring leading to infertility, ectopic pregnancy, chronic pelvic pain, problems in pregnancy, abscesses
syphilis
cause
symptoms
diagnosis
treatment
pregnancy
Cause: Treponema pallidum – spirochete bacterium
Symptoms: Can be asymptomatic.
Primary: Early in infection get a painless sore(s) – chancre, at infection site
Secondary: May get rash, hair loss or flu-like symptoms
Latent syphilis: Can be years with no symptoms
Tertiary: paralysis, blindness and other conditions
Diagnosis: Depends on stage. Can include clinical history, physical exam, lab tests (microscopy, NAAT, serological/EIA), RPR/VDRL tests (blood) antibody levels (Rapid plasma regain/venereal disease research laboratory)
Treatment (July 2019 guidance):
Early (primary, secondary & early latent):
First line is single dose of benzathine benzylpenicillin 2.4MU i/m
Alternatives include: Procaine penicillin G 600,000U i/m daily for 10 days, 100mg doxycycline PO BD 14d, erythromycin 500mg PO QDS 14d and others
Late latent:
First line is Benzathine benzylpenicillin 2.4MU i/m once a week for 3 weeks
Alternatives: doxycycline 100mg PO BD 28d or amoxicillin 2g PO TDS AND probenecid 500mg QDS 28 days).
Pregnancy: For early syphilis, First line as above if trimester 1&2, if 3rd trimester, 2 doses (Day 1 and Day 8); for late latent syphilis, similar to 1st line above (doses on Day 1, 8 and 15)
Note: Other regimens required if neurosyphilis (and similar in pregnancy)
HPV / Genital Warts
cause
symptoms
diagnosis
treatment
prevention
complications
Cause: HPV – human papilloma virus, group I (dsDNA virus)
HPV6 and 11 commonly lead to genital warts
HPV16 and 18 commonly lead to cervical cancer (and others
Symptoms/diagnosis: Warts by examination. For cervical cancer may have unusual bleeding – Pap test screening to detect.
Treatment: Many cleared by immune system. Podophyllotoxin and trichloroacetic acid (TCA) useful on soft warts. Ablative methods e.g. excision or cryotherapy better if keratinised. Imiquimod cream for either.
Prevention: Vaccine Gardasil (HPV16, 18 and 6, 11) – refer to UK Vaccination Schedule for further information. Given to all 12-13yr old girls and boys.
Complications: Can lead to pre-malignant tumours that can lead to cancer e.g., of cervix (HPV16 and 18 cause majority of cervical cancers)
BUT very much on the decline with vaccination despite small rise last year
HPV / Genital Warts
cause
symptoms
diagnosis
treatment
prevention
complications
Cause: HPV – human papilloma virus, group I (dsDNA virus)
HPV6 and 11 commonly lead to genital warts
HPV16 and 18 commonly lead to cervical cancer (and others
Symptoms/diagnosis: Warts by examination. For cervical cancer may have unusual bleeding – Pap test screening to detect.
Treatment: Many cleared by immune system. Podophyllotoxin and trichloroacetic acid (TCA) useful on soft warts. Ablative methods e.g. excision or cryotherapy better if keratinised. Imiquimod cream for either.
Prevention: Vaccine Gardasil (HPV16, 18 and 6, 11) – refer to UK Vaccination Schedule for further information. Given to all 12-13yr old girls and boys.
Complications: Can lead to pre-malignant tumours that can lead to cancer e.g., of cervix (HPV16 and 18 cause majority of cervical cancers)
BUT very much on the decline with vaccination despite small rise last year
Genital Herpes
causes
symptoms
diagnosis
general care
treatment
Cause: HSV, usually HSV-2 (can be HSV-1 which causes cold sores/oral herpes, Group I, dsDNA virus)
Symptoms: blisters and sores, painful and itchy. Can have pain on urination. Last few days (1-2 weeks, initially can be 2-4 weeks). Can be triggered – e.g. stress, illness…
Diagnosis: NAAT can be used to detect virus and type (swab)
General care: Saline, analgesia, topical anaesthetics (e.g. 5% lidocaine)
Treatment: Oral antivirals if within 5 days of start of episode. Preferred regimens: Aciclovir 400mg TDS, Valaciclovir 500mg BD; alternatives: Famciclovir 250mg TDS or acyclovir 200mg 5 times/day
Treatment reduces severity and duration only
HIV
causes
symptoms
diagnosis
treatment
Cause: HIV – human immunodeficiency virus
Symptoms: Initially can have a flu-like illness then no symptoms for years.
When immune system damaged enough can suffer: weight loss, diarrhoea, night sweats, infections…
Diagnosis: typically by blood test
Treatment: See HIV lectures and reference material
Post-exposure prophylaxis (PEP) can be used for <72hrs exposure
Pre-exposure prophylaxis (PrEP) to prevent transmission of infection
Hepatitis B
causes
symptoms
diagnosis
treatment
vaccine ?
Cause: HBV. An orthohepadnavirus (group VII dsDNA-RT).
Infections can be acute (more common) or chronic. 1-3 months for 95% cases (acute) / 6 months+ chronic (can lead to cirrhosis and cancer of liver).
Symptoms: Often asymptomatic. Prodromal: flu-like symptoms (rash, fever, malaise etc.) can occurs ~2 weeks before onset of jaundice. Right upper abdominal pain, nausea, fatigue, darker urine, lighter stools, vomiting. Chronic: jaundice, fatigue, loss appetite but can be asymptomatic
Diagnosis: blood test (antigens, antibodies and DNA)
Treatment: analgesia, anti-emetic. Self-care: avoid alcohol, minimise transmission
Vaccine: available for at risk groups
From August 2017 is part of routine vaccination for babies in UK
Treatment for chronic varies, can include e.g. tenofovir disoproxil fumarate (TDF) or alafenamide (TAF), pegylated interferon alpha or Entecavir (to prevent liver failure)
Hepatitis C
causes
transmission
symptoms
diagnosis
treatment
complications
Cause: HCV – Hepatitis C Virus. Acute or chronic, 15-45% clear spontaneously
Transmission: often IV drug use but possibly can be STI
Symptoms: Usually asymptomatic. Acute can be fatigue, nausea, decreased appetite, weight loss, joint/muscle pain (overall similar to Hep A and Hep B)
Diagnosis: e.g. ELISA or PCR-based testing of blood
Treatment: Goal is to CURE. Interferon-based treatment no longer recommended. Direct-acting antiviral (DAAs) better options now. Target HCV life cycle stages
Choice depends on genotype of HCV, stage, previous treatment, co-morbidities etc. DAAs used alone or in combinations, examples are:
NS3/4 protease inhibitors: paritaprevir, glecaprevir, grazoprevir, voxilaprevir. NS5A inhibitors: Daclatasvir, Ledipasvir, Ombitasvir, Elbasvir, pibrentasvir, velpatasvir. NS5B polymerase inhibitors: sofosbuvir, dasabuvir
Most recent approved by NICE: sofosbuvir + velpatasvir + voxilaprevir (HCV1-6 with previous DAA treatment, 12 weeks, or HCV3 without previous DAA, 8 weeks)
Complications: ~1/3 develop liver cirrhosis and some liver cancer
Trichomonas vaginalis
cause
symptom
diagnosis
treatment
Cause: Trichomonas vaginalis – anaerobic protozoal parasite
Symptoms: Commonly asymptomatic (50%)
In women – vaginal discharge, thick/thin/frothy yellow-green, more than usual, may have fishy smell, soreness/itching/swelling, tummy pain, pain/discomfort on urination or sex
In men – thin white discharge, pain on urination/ejaculation, increased frequency, soreness/redness/swelling
Diagnosis: Exam, testing of swab or urine (men), NAAT, culture, POCT, microscopy
Treatment: Updated BASHH guidance in June 2022
Metronidazole: 400–500mg twice daily for 7 days. *Alternatively, 2g single dose. (Avoid 2g dose in pregnancy, use 400mg BD, 7 days).
*Previous guidance was the opposite.
Contact tracing
pubic lice
cause
diagnosis
symptom
treatment
pregnancy saftey?
Cause: Lice (Phthirus pubis), commonly by sexual contact but can be via bedding or clothes
Diagnosis: Finding adult lice/eggs, can confirm with microscopy
Symptoms: Itching, irritation/inflammation, bites, blood on clothes/skin
Treatment: e.g. 1% Permethrin cream or malathion 0.5% aqueous solution. Following application (as directed), second application 3-7 days later.
Pregnancy: Permethrin is safe to use
