STI Pathologies Flashcards
Please see general info regarding STIs before we start:
- Most people with STIs are asymptomatic most of the time - hence they are still rife
- Delay in diagnosis can lead to an increased chance of transmission and complications
- Having an STI can be psychologically traumatising for many people. Often more damaging than the physical effects.
- Patients need information, a sensitive approach and appropriate follow up.
- If you diagnose someone with say chlamydia but haven’t made arrangements for their sexual contact(s) to be treated then you haven’t finished the job.
- STI control is a multidisciplinary field
Gonorrhea
What is causative organism?
- Neisseria gonorrhoeae
Gonorrhoea
SSx?
Male:
- 10% of males have no symptoms though might have clinical signs if examined. Thick, profuse yellow discharge, dysuria. Rectal and pharyngeal infection often asymptomatic.
Female:
- >50% have no symptoms.
- vaginal discharge, dysuria or intermenstrual/post-coital bleeding
Gonorrhoea
Complications?
Male:
- Epididymitis
Female:
- PID, Abscess
Both
- Acute monoarthritis usually elbow or shoulder. Disseminated Gonococcal Infection: skin lesions - pustular with halo
Gonorrhoea
What is the incubation period?
Average 5-6 days
Gonorrhoea
Epidemiology?
- Approx 150 cases/yr in Grampian. Much less common than chlamydia. Most cases are in men, often in men who have sex with men (MSM).
Gonorrhoea
How do we make Dx?
- Nucleic Acid amplification test (NAAT) on urine or swab from affected site (vagina, rectum, throat)
- Gram stained smear from urethra/cervix/rectum in symptomatic people.
- Culture of swab-obtained specimen from an exposed site using highly selective lysed blood agar in a 5% CO2 environment. Should be done for all confirmed cases to assess antibiotic sensitivity.
Gonorrhoea
Rx?
- Blind treatment with ceftriaxone 500mg im once plus Azithromycin 1g.
- Can also treat according to antibiotic sensitivities
Gonorrhoea
Follow up?
Test of cure at 2 weeks and test of reinfection at 3 months
Chlamydia
Caused by?
Chlamydia trachomatis serovars D to K
Chlamydia
SSx?
Men:
- >70% asymptomatic
- Slight watery discharge, dysuria,
Female:
- >80% asymptomatic
- vaginal discharge, dysuria, intermenstrual/post-coital bleeding.
Both
- Conjunctivitis
Chlamydia
Complications?
Male:
- Epididymitis
Female:
- PID and hence ectopic pregnancy, pelvic pain and infertility. Probably only ~1% of women who get chlamydia will develop a problem with their fertility
Both:
- Reactive arthritis/ Reiter’s syndrome – urethritis/cervicitis + conjunctivitis + arthritis
Chlamydia
Epidemiology?
Common. Approx 2000/yr in Grampian. Most cases in people under 25, especially sexually active teenage women.
Chlamydia
How do we make Dx?
- First void urine in men.
- Self-taken or clinician-taken swab from cervix, urethra, rectum as appropriate.
- All specimens tested using a NAAT
Chlamydia
Rx?
- Azithromycin 1g po once.
- Doxycycline 100mg bd 1 week if rectal infection.
Chlamydia
Follow up?
Test for reinfection at 3-12 months. Earlier test of cure not needed unless symptoms persist.
Herpes
Caused by?
Herpes Simplex Virus types 1 and 2
Herpes
SSx?
- 80% have no symptoms. The rest have recurring symptoms – monthly, annually. Burning/itching then blistering then tender ulceration.
- Tender inguinal lymphadenopathy. Flu-like symptoms.
- Dysuria, Neuralgic pain in back, pelvis and legs,
Herpes
Complications?
Autonomic neuropathy (urinary retention), neonatal infection, secondary infection
Herpes
Incubation period?
About 5 days to months. Some people never report symptoms
Herpes
Epidemiology?
Very common ~ 15-20% of UK population has it. Both strains equally common in genital infection. Roughly equal between sexes. HSV2 is important co-factor for HIV transmission.
Herpes
How do we make Dx?
- Clinical impression.
- Swab from lesion tested using PCR.
Herpes
Rx?
- Primary outbreak:
- Aciclovir: various regimens – eg 400mg tds for 5 days Lidocaine ointment
- Infrequent recurrences:
- Lidocaine ointment. Aciclovir 1.2g once daily until symptoms gone (1-3 days)
- Frequent recurrences:
- Aciclovir 400bd long-term as suppression.
Trichomoniasis
Causative organism?
Trichomonas vaginalis
Trichomoniasis
SSx?
- Men: usually asymptomatic
- Women: 10-30% asymptomatic
- Profuse thin vaginal discharge - greenish, frothy and foul smelling. Vulvitis.
Trichomoniasis
Epidemiology?
Uncommon, approx 100/yr in Grampian. More common in middle aged women than some other STIs are.
Trichomoniasis
Complications?
Miscarriage and preterm labour
Trichomoniasis
How do we make Dx?
- PCR on a vaginal swab. NB not on urine yet so no test for men.
- Point of Care - Microscopy of wet preparation of vaginal discharge.
Trichomoniasis
Rx?
Metronidazole 400mg po bd for 5 days or 2g single dose.
Anogenital Warts
Caused by?
Human Papilloma Virus types 6 and 11 (and occasionally type 1). (NB different strains from those that cause cervical cancer.
Anogenital warts
SSx?
Lumps with a surface texture of a small cauliflower. Occasionally itching or bleeding especially if perianal or intraurethral.
Anogenital warts
Epidemiology?
>90% of UK population have a genital HPV infection at some point in their life.
Only about 20% of those infected with a wart-causing strain of human papilloma virus get warts.
A drop in cases is anticipated in response to quadrivalent HPV vaccine
Anogenital warts
Complications?
None common
Anogenital warts
How do we make Dx?
Appearance. Biopsy if unusual – to exclude intraepithelial neoplasia, but this is rarely needed.
Anogenital warts
Rx?
- Podophyllotoxin (brands warticon and condyline), imiquimod (brand Aldara). Both home treatments. Others – cryotherapy
- Bulky warts – diathermy, scissor removal.
Syphilis
Causative organism?
Treponema pallidum subspecies pallidum
Syphillis
SSx?
Stages?
Very diverse presentation
Often entirely asymptomatic or mild symptoms which go unreported.
- Primary stage: Local ulcer
- Secondary: Rash, mucosal ulceration, neuro symptoms, patchy alopecia
- Early latent: no symptoms but <2 yrs since diagnosis
- Late latent: no symptoms but >2yrs since diagnosis
- Tertiary: Neurological, cardiovascular or gummatous – skin lesions, (all v rare).
Syphillis
Epidemiology?
Approx 20 cases/yr in Grampian. >90% of cases in Scotland are in men who’ve had sex with men.
Syphillis
Complications?
neurosyphilis – cranial nerve palsies are commonest, cardiac or aortal involvement.
Congenital syphilis (extremely rare in Scotland).
Syphillis
How do we make Dx?
- Clinical signs
- Serology for TP IgGEIA, TPPA and RPR PCR on sample from an ulcer
Syphillis
Rx?
- Early (<2 yrs and no neurological involvement):
- Benzathine penicillin 2.4 MU im once Or Doxycycline 100mg bd po 2 weeks
- Late (>2 years) and no neurological involvement:
- Benzathine penicillin 2.4MU im weekly for 3 doses Doxycycline 100mg bd po 28 days
