Pathogenesis of HIV and the major Sexually Transmitted Infections Flashcards
Name some common bacteria which cause STI’s in the UK
N. Gonorrhoea
C. Trachomatis
Ureaplasma
Mycoplasma
Name some viruses that cause STI’s in the UK
Herpes Simplex Virus
Human Papilloma Virus
Pox Virus
HIV / Hep B (Uncommon)
How can infections be transmitted from mother to baby?
- in utero (trans placental)
- peri natal : eye mucous membrane, present in breast milk.
What organism is a gram negative coccus (diplococus)?
Neisseria gonorrhoeae
What are the 3 cell wall layers of N. Gonorrhoea (a gram negative bac)
1) Outer cytoplasmic membrane (lipo-oligosaccharides)
2) Thin Peptidoglycan cell wall
3) Inner cytoplasmic membrane
What are the local complications of N. Gonorrhoea?
- epididymitis, prostatitis
- peritionitis
- fitz-hugh-curtis syndrome
What are the metastatic complications of N. Gonorrohoea?
- bacteraemia
- arthritis
- dermatitis
What are the effects of Gonorrhoea during pregnancy?
- premature labour
- neonatal conjunctivitis
How is N. Gonorrhoea diagnosed?
Microscopy - urethral swab
Culture - endocervical (women), urethral (men)
Nucleic Acid Amplification Test - PCR
What are the treatments of N. Gonorrhoea?
- beta Lactams (Benzyl Penicillin, amoxicillin)
- Cephalosporins (cefixime, ceftriaxone)
- Fluoroquinolones (ciprofloaxacin)
What is non-gonococcal urethritis?
It is inflammation of the urethra that is not caused by gonorrhea. It can be caused by Chlamydia Trachomatis.
What are the symptoms of Chlamydia?
- Urethritis (inflammation of urethra)
- Cervicitis (inflammation of cervix)
- dysuria (painful urination)
What are some complications of a Chlamydial Infection?
- Tubal Infertility (ectopic pregnancy)
- Neonatal conjunctivitis
- Infant Pneumonia
- Reiter’s Syndrome (affects men = arthritis, conjunctivitis, urethritis)
What is the treatment of Chlamydia?
Azithromycin
Doxycycline
What is Pelvic Inflammatory Disease?
inflammation of the female genital tract, accompanied by fever and lower abdominal pain.
Increases risk of infertility
What are the organisms which cause Pelvic Inflammatory Disease?
N. Gonorrhoeae
C. Trachomatis
Haemophilius
Which types of Human Papilloma virus are associated with genital warts and cancer?
HPV 6 and 11 = warts
HPV 16 and 18 = cancer
What is condylomata accuminata? and how is it treated?
Genital warts
Treated:
- burn
- freeze
- cut
- imiquimod (topical cream)
What causes Genital Herpes and what are the symptoms?
Cause : Herpes Simplex Virus (double stranded DNA virus)
Symptoms:
- pain, itching
- dysuria (pain on urination)
- vaginal/urethral discharge
- ulcers
Why does genital herpes recur and persist?
The virus infects sensory neuron cells and spreads to the sacral nerve ganglia where it is latent (dormant).
What is the treatment of Genital Herpes?
Acyclovir
What are the complications of genital herpes?
- dissemination (spreads)
- meningitis
- encephalitis
- urinary retention
- sacral nerve parasthesiae (abnormal sensation)
What causes Syphilis?
Treponema Pallidum (Spirochaete - double membrane bacteria)
How does Syphilis spread?
Via lymphatics and blood stream within days
What is the average incubation period of syphilis?
21 days
How does syphilis present in the 2nd stage?
Skin:
- Rash
- Condylomata Lata (warty erosions)
CNS:
headache
Overall:
fever, malaise, weight loss
How does syphilis present in the 3rd stage?
Neurosyphilis;
- meingovascular
- personality change
- don’t react to light ect.
Cardiovascular:
Aortitis
What is the treatment of Syphilis?
Penicillin
What infection causes Jarish - Herxheimer reaction?
Syphilis causes Jarish Herxheimer reaction.
What is Trichomoniasis and what causes it?
It is an STI that is caused by the parasite - Trichomonas Vaginalis.
It presents with:
- Green, thick Vaginal discharge
- inflammation around vagina
- dysuria (pain when passing urine)
What is Bacterial (anaerobic) vaginosis? (cause and presentation)
It is a vaginal infection caused by anaerobic bacteria and Gardenella Vaginitis.
It causes water discharge with a fishy odour.
How is Bacterial Vaginosis treated?
-Metronidazole
What are the factors that cause Candidiasis (thrush / balanitis) infection?
- oral contraceptives
- antibiotics (inhibit normal flora)
- poorly controlled diabetes
What are the symptoms and signs of Candidiasis?
Vulval, vaginal, penile itching / irritation
thick discharge / white plaques.
What Is the treatment for candida albicans?
Fluconazole
or topical cream
What is HIV?
HIV is a retrovirus that has a high rate of mutability. It attacks the immune system,
How doe HIV enter the host cell and affect the immune system?
The virus interacts to the CD4 receptor and the CC5R chemokine receptor to gin access to the cell.
In the cytoplasm, revers transcriptase occurs.
the dsDNA is the imported into the nucleus and incorporated into the cell genome.
This causes the loss of CD4+ve T cells.
So normally non pathogenic organisms can cause infection.
What are the symptoms of a primary HIV infection?
- fever
- pharyngitis
- lymphadenopathy
- rash
How is HIV diagnosed ?
- antibody testing
- PCR
- CD4 cell count
