Pathogenesis of HIV and the major sexually Transmitted Infections Flashcards
What is the definition of STI?
Sexually transmitted infection
infetions which are transmitted person to person by sexual contact
What is the definition of STD?
Sexually transmitted infection
evidence of disease i.e. signs and symptoms present
How are STI caused specifically via sexual contact?
mucous membrane contact
exchange of body fluids
What are 3 common concepts of STI’s?
risk of transmissions = number of sexual partners - increased risk with use of non barrier/no contraception
Patients with one STD likely to have other STD’s
Tracing of people who may have come into contact with infected person is important
What kind of an organism is Neisseria gonorrhoeae?
gram negative
diplococcus - in pairs
Where does gonorrhoeae multiply and therefore how does the body destroy it?
intra-cellularly
therefore destroyed via phagocytosis by neutrophils
How does gonorrhoeae attach to mucosal epithelial cells?
pili on the surface
Where does gonorrhoeae present at in the body?
GU tract
rectum
oropharynx
What are the symptoms of gonorrhoeae?
urethral discharge
dysuria
What are the complications of gonorrhoeae? (inc in pregnancy)
epididymitis
prostitis
barthonilitis - inflammation of Bartholin’s glands in the vagina
salpingitis - inflammation of the fallopian tubes
PID
peritonitis
Fitz-Hugh-Curtis Syndrome (perihepatitis)
Diseminated Gonococcal Infection - spread of infection to the rest of the body e.g. Conjuctivitis
Pregnancy: spontaneous abortion, premature labour
What is the treatment for gonorrhoeae?
B-lactams e.g. BenzylPenicillin
Cephalosporins e.g. cefixime
What two pathogens cause non gonococcal urethritis?
chlamydia trachomatis
Ureaplasma urealyticum
How is gonorrhoeae, syphilis, HIV and chlamydia diagnoised?
Nucleic acid amplification test (NAAT)
What is the treatment for non gonococcal urethritis?
Doxycycline
What are the symptoms of chlamydia?
dysuria frequency urgency discharge abnormal bleeding e.g. after sex, between periods
What are the complications of chlamydia?
PID
Epididymitis
Conjuctiva (inc neonates)
Reiters syndrome
What is Reiters syndrome?
Arthritis
Conjuctivitis
Urethritis
Skin lesions
What is the treatment for chlamydia?
Azithromycin
Doxyclycline
What is the treatment for HPV warts?
Burn Freeze Cut Imiquimod - immune response modifier Salicylic acid Liquid nitrogen
What are the signs and symptoms of genital herpes?
pain itching dysuria vaginal/urethral discharge ulcers
What is the treatment of genital herpes?
aciclovir
What are the complications of genital herpes?
dissemination
meningitis
encephalitis
sacral nerve parasthesiae which causes urinary retention
What organism causes syphilis?
Treponema pallidium
Where does treponema pallidium penetrate and travel round the body?
penetrates intact mucous membranes
disseminates within days via lymphatics/bloodstream
What is obliterative endarteritis and what infection is it associated with?
inflammation of the intima or inner lining of an artery
results in an occlusion of the lumen of the artery
Syphilis
What do the 3 stages of syphilis involve?
1) Painless lesion
2) Redness. Rash, wart like lesions on genitalia, mucous patches, lymphadenopathy, headache, fever, malaise, weight loss
3) serious CNS symptoms e.g. hemiplegia, seizures,
CV symptoms - aortic regurgitation, saccular aneurysm Other: granulomatous reactions
What is the treatment for syphilis?
penicillin based
What is Jarish-Herxheimer reaction?
commonest in secondary stage of syphilis fevers chills myalgia hypersensitivity reaction - organism lysis NOTE: feels worse with penicillin
What pathogen causes trichomoniasis?
trichomonas vaginalis
protazoa
What are the symptoms of trichomoniasis?
green frothy vaginal discharge
mucosal inflammation
What is the treatment for trichomoniasis?
metronidazole
What is bacterial vaginosis (BV)?
Caused by reduced vaginal lactobacilli
increased Gardnerella vaginalis and anaerobes
How is HIV transmitted?
Sexual - genital/colonic mucosa
Exposure to other infected fluids e.g. blood/blood products
Mother to infant
Why do opportunistic infections occur in those with HIV?
loss of CD4 T cells
Reporting of stage based on CD4 count
For more HIV questions see…
Antivirals
What has been implemented to prevent STI’s?
Referral to GUM clinics Free barrier contraception Chlamydia screening Universal HIV screening for those with STI's Encouraging contact tracing Vaccinations e.g. HPV
What 2 organisms can cause PID?
N.gonorrhoea
C.trachomatis
How is trichomoniasis diagnoised?
Vaginal swab - microscopy and culture
What is the treatment for bacterial vaginosis?
Metronidazole
What are the symptoms of bacterial vaginosis?
watery, fishy odoured discharge
