L11 - Genital Infections Flashcards
1. Describe the mechanisms of infection of the genital tract in relation to the immune / inflammation response seen and relate this to the pathology. 2. Describe the abnormalities in the composition and regulation of the normal microbiological flora of the genital tract lead to clinical symptoms and how this can pre-dispose to genital infections 3. Describe and recognise the main microbiological features of the common genital infections (gram negative, gram positive) 4. To understand what a f
State examples of sexually transmitted infections caused by bacteria?
- Neisseria Gonorrhoeae
- Chlamydia Trachomatis
- Trichomonas Vaginalis
- Syphilis (Treponema Pallidum)
State examples of sexually transmitted infections caused by viruses?
- Human Papilloma virus (HPV)
- Herpes simplex virus (HSV)
- Human immunodeficiency virus (HIV)
Examples of sexually transmitted viruses caused by mites?
Pediculosis pubis
State examples of non-sexually transmitted infections caused by bacteria?
Bacterial Vaginosis
Non-sexually transmitted infection caused by a fungus?
Candidiasis
Non-sexually transmitted infection caused by a virus?
rhymes with pollosum bontagiosum
Molluscum contagiosum
Briefly describe host defences against genital infection?
Innate
- internal: phagocytes, macrophages, inflammation
- external: skin, mucous membranes, healthy flora
Adaptive
- humoral (immunoglobulin), B-cells, T-cells
Examples of normal vaginal flora and their two categories?
Faecal flora
- lactobacilli
- group B streptococci
- Coliforms (E-coli)
- anaerobes
- enterococci
Skin flora
- coagulase negative staphylococci
- diphtheroids
What is the normal pH range for the vagina?
Between 4 -5
Slightly acidic
Describe how the pH in the vagina is maintained?
- Oestrogen / progesterone leads to release of glycogen.
- Lactobacilli break this down into lactic acid.
- Creates acidic environment
- Facilitates growth of lactobacilli
- Inhibits the growth of harmful bacteria
Describe host defences in males?
Mechanical barrier (epithelial mucous membrane) - length of urethra and urinary flushes protect against most infective organisms.
Innate: phagocytes, complement
Adaptive: Ig, B-cell, T-cell
Case-study
Patient, Female, 25 y/o, discharge with abnormal odour (fishy smell)
Bacterial Vaginosis
- thin, white, homogenous discharge coating walls of vagina and vestibule
Many women are asymptomatic
Describe the Hay/Ison criteria of bacterial vaginosis?
Grade 1 : normal - Lactobacillus morphocytes predominate Grade 2 : intermediate - mixed flora with some lactobacilli present - some Gardnerella or Mobiluncus morphocytes present Grade 3 - mainly Gardnerella / Mobiluncus - few lactobacilli
What is the Ansel critera for Bacterial vaginosis?
- Thin, white, homogenous discharge
- Clue cells on microscopy of wet mount
- pH of vaginal fluid >4.5
- Fishy odour
Common risk factors for bacterial vaginosis?
Overwashing
Recent change of sexual partner.
Smoking.
Presence of an STI
- not sexually transmitted
Case study:
Female patient, thick white discharge, itchy
Vulvovaginal candidiasis (thrush)
What is the most common bacteria causing thrush?
Candida Albicans >90%
also: Candida galbrata, candida tropicalis, candida krusei, candida parapsilosis
What are some symptoms of vulvovaginal candidiasis?
- vulval itching
- vulval soreness
- vaginal discharge
- superficial dyspareunia
- external dysuria
Dysuria
painful or difficult urination
Dyspareunia
Difficult or painful sexual intercourse
Patient, female, 25 y/o, profuse discharge
Trichomonas Vaginalis
- Vulval itching
- Dysuria
- Strawberry cervix
- can cause preterm delivery and low birth rate
What is Pelvic inflammatory disease?
Clinical syndrome associated with ascending spread of microorganisms from endocervix to endometrium, fallopian tubes etc
What may cause Pelvic inflammatory disease?
Sexually transmitted infections:
- Chlamydia trachomatis (most common)
- Neisseria gonorrhea
- mycoplasma genitalium
Dysmenorrhea
Menstrual cramps
What bacteria caused Gonorrhoea?
Gram-negative coccus Neisseria Gonorrhoeae
Describe what happens with Neisseria Gonorrhoeae enters a host?
- Invades non-ciliated epithelial cells which internalise the bacteria.
- bacteria multiply within intracellular vacuoles so protected from phagocytes and anti-bodies
- vacuoles fuse with basement membrane and discharge bacterial contents
Describe Trichomonas infection?
- Trichomonas vaginalis is a protozoan parasite
- and causes vaginitis with lots of discharge.
Why is it difficult to identify chlamydia trachomatis?
Can’t gram stain chlamydia
- intracellular parasite
- lacks peptidoglycan wall
- can’t retain the colour
State some symptoms of Pelvic inflammatory disease?
- Lower abdominal pain, typically bilateral
- Deep dyspareunia
- abnormal vaginal bleeding
- abnormal discharge
What is the incubation period of Neisseria gonorrhoeae?
2 - 5 days
What are the stages of syphilis?
1.Primary
- Secondary
- latent (early / late) - Tertiary
- neurosyphilis
- cardiovascular syphilis
- gumma
Gumma
Soft, non-cancerous growth resulting from the tertiary stage of syphilis.
Describe a syphilis sore?
aka chancre (primary)
- sore where the syphilis infection entered your body,
- firm, round and usually painless.
What may be a symptom of a patient with secondary syphilis?
Macula papilla rash
Tertiary syphilis?
treated with
affects where
- Treated with penicillin.
- Lots of neurological symptoms.
- Affects liver, brain and eyes.
What asymptomatic infections are screened for in a sexual health clinic?
- Chlamydia trachomatis
- Neisseria gonorrhoeae
- HIV
- Syphilis
