STIs Flashcards
define and give examples of STIs
A ‘Sexually transmitted infection’ (STI) is an infection which is predominantly sexually transmitted; for example Chlamydia trachomatis or HIV. Other infections can be sexually transmissible but aren’t usually classed as STIs eg hepatitis A, hepatitis C, Zika and giardiasis.
define and give examples of STDs
An STI is the infection, eg Human Papilloma Virus, whereas an STD is the disease(s) it causes; eg warts.
gonorrhoea: organism
neisseria gonorrhoeae
gonorrhoea: symptoms men
10% asymptomatic but may have clinical signs
thick, profuse yellow discharge
dysuria
rectal and pharyngeal infection often asymptomatic
gonorrhoea: symptoms women
> 50% asymptomatic
vaginal discharge
dysuria
intermenstrual/post-coital bleeding
gonorrhoea: complications
epididymitis - male
female - pelvic inflammatory disease, bartholin’s abscess (gonococcal ophthalmia neonatorum)
both
acute monoarthritis usually elbow or shoulder
disseminated gonococcal infection - skin lesions, pustular with halo
gonorrhoea: incubation period
5-6 days average
2 days - 2 weeks
gonorrhoea: diagnosis
Nucleic Acid Amplification Test (NAAT) on urine or swab from an exposed site – vagina, rectum, throat. Could be self-obtained or clinician-obtained.
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: treatment
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: organism
Chlamydia trachomatis serovars D to K
chlamydia: symptoms
Men: >70% asymptomatic Slight watery discharge, dysuria, Women: >80% asymptomatic vaginal discharge, dysuria, intermenstrual/post-coital bleeding. Both: Conjunctivitis
chlamydia: complications
Men Epididymitis.
Women: 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: diagnosis
First void urine in men. Self-taken or clinician-taken swab from cervix, urethra, rectum as appropriate.
All specimens tested using a NAAT
chlamydia: treatment
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: organism
HSV 1 + 2
herpes: symptoms
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.
herpes: diagnosis
Clinical impression.
Swab from lesion tested using PCR.
herpes: treatment primary outbreak
Aciclovir: various regimens – eg 400mg tds for 5 days
Lidocaine ointment
herpes: treatment infrequent recurrences
Lidocaine ointment. Aciclovir 1.2g once daily until symptoms gone (1-3 days)
herpes: treatment frequent recurrences
Aciclovir 400bd long-term as suppression.
trichomoniasis: organism
trichomonas vaginalis
trichomoniasis: symptoms
Men: usually asymptomatic
Women: 10-30% asymptomatic
Profuse thin vaginal discharge - greenish, frothy and foul smelling. Vulvitis
trichomoniasis: complications
miscarriage and preterm labour
trichomoniasis: diagnosis
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: treatment
Metronidazole 400mg po bd for 5 days or 2g single dose.
anogenital warts: organism
Human Papilloma Virus types 6 and 11 (and occasionally type 1). (NB different strains from those that cause cervical cancer.
anogenital warts: symptoms
Lumps with a surface texture of a small cauliflower. Occasionally itching or bleeding especially if perianal or intraurethral.
anogenital warts: complications
None common. Neonatal laryngeal papillomatosis.
anogenital warts: diagnosis
Appearance. Biopsy if unusual – to exclude intraepithelial neoplasia, but this is rarely needed
anogenital warts: treatment
Podophyllotoxin (brands warticon and condyline), imiquimod (brand Aldara). Both home treatments.
Others – cryotherapy
Bulky warts – diathermy, scissor removal.
syphilis: organism
Treponema pallidum subspecies pallidum
syphilis: symptoms primary
Local ulcer (chancre)
syphilis: symptoms secondary
Rash, mucosal ulceration, neuro symptoms, patchy alopecia, other symptoms.
syphilis: symptoms early latent
no symptoms but <2years since caught.
syphilis: symptoms late latent
no symptoms but >2 years since caught.
syphilis: symptoms tertiary
Neurological, cardiovascular or gummatous – skin lesions, (all v rare).
syphilis: complications
neurosyphilis – cranial nerve palsies are commonest, cardiac or aortal involvement. Congenital syphilis (extremely rare in Scotland).
syphilis: incubation period
9 to 90 days until appearance of chancre. But can be asymptomatic.
syphilis: diagnosis
Clinical signs
Serology for TP IgGEIA, TPPA and RPR
PCR on sample from an ulcer
syphilis: treatment
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
