Week 10 Urinary and reproductive infections Flashcards
Physiological differences between male and female reproductive systems
Females have shorter urethra, opening exposed to perineum
diseases of urinary tract (4)
bacteriuria (lower tract), cystitis (bladder), pyelonephritis (from lower tract to kidney into blood), leptospirosis
Describe normal microbiota in women before puberty
Scanty and mixed, derived from colon and skin
Describe normal microbiota in women during child bearing years
LActobacilli (66%), anaerobic negative rods, positive cocci, aerobic coryneforms, coagulase negative staph, streptococci
Describe normal microbiota in women post menopause
Anaerobic bacteria (bacteroides species), mycoplasma, low density of gram negative rods
Why do normal microflora change with age in women
Due to changes in hormones
Describe normal microbiota in men
Coagulase negative staph, group D strep, coryneforms, sometimes mycoplasma
Low in numbers
Why do normal microbiota differ between men and women
Less contamination of urine by indigenous flora, longer urethra
Urinary tract infection (asymptomatic)
Asymptomatic bacteriuria: infection at any site along urinary tract
BActeria adhere to bladder and are not flushed out at micturition, may gain access to bladder via the lumen or outside of the catheter
How does e.coli adhere to urinary tract
P pili bind to surface of urinary tract
Symptomatic UTI
Involves lower UT
Cystitis = bladder infection
Can be haemorrhagic
Need antibiotics at this stage
Cystitis symptoms
Urgency, frequency, dysuria (painful or burning urination)
Haemorrhagic cystitis symptoms
Urgency, frequency, dysuria (painful or burning urination)
Blood in urine (haematuria, gross or microscopic)
How does gender difference in UTI prevalence change with age
Childhood = similar
Adulthood (child bearing period) = females
Old age = male slightly higher than females
Pyelonephritis
Infection of kidneys (upper UT)
Bacteria use flagella to make way up ureter into kidneys
Chills, nausea, fever, vomiting
Leptospirosis
Caused by leptospira interrogans
Bacteria shed in animal urine contaminates water
Entry into human causes severe kidney or liver disease
6 diseases of genital tract (least to most common)
Syphilis
AIDS, genital herpes and gonorrhoea, chlamydia, trichomoniasis
Gonorrhoea
Gram neg diplococcus Neisseria gonorrhoea, mostly affects 15-24
Females more likely to develop from a single exposure
Female gonorrhoea symptoms
Cervix infected, not vagina due to cell type (columnar vs stratified squamous)
Male gonorrhoea symptoms
Painful urination and pus
Complications of gonorrhoea (6)
Gonorrhoeal endocarditis, gonorrhoeal meningitis, gonorrhoeal arthritis, ophthalmia neonatorum, pharyngeal gonorrhoea, anal gonorrhoea
Syphilis
Treponema pallidum (spirochaete)
Cultured in cells only
Incubation period of 2-3 weeks
Syphilis stages (3)
- Primary
Small hard chancre (sore) at site of infection with highly infectious exudate from centre, positive serological test - Secondary
Skin rashes, hair loss, malaise, mild fever, lesions of rash containing many spirochaetes, if not treated becomes latent (can later be reactivated) - Tertiary stage
Gumma lesions: ulceration of skin and roof of mouth
Outer layer of bacterial lipids inhibits immune response ‘teflon coated’
Cell mediated immune response to clear
Syphilis diagnosis (3)
Venereal disease research laboratory (VDRL) serological screening- gold standard
Rapid plasma reagin (RPR) test- serological
Fluorescent treponema antibody absorption (FTA-abs) test using patient’s serum specific antibody
Syphilis treatment
Benzathine penicillin
In penicillin allergic patients: erythromycin or tetracycline
BActerial vaginitis cause
Decreased lactobacilli population, acidity not maintained, opportunistic infection- bacteroides and gram negative
Fungal candidiasis
Candida albicans colonises mucus membranes when lactobacilli population fails to maintain acidity
Candidiasis symptoms
Severe itching, irritation, thick yellow discharge
Candidiasis predisposing conditions (3)
Pregnancy (incnreased glycogen in vagina)
Oral contraceptive
Broad spectrum antibiotics which suppress normal microbiota
Trichomoniasis
Trichomonas vaginalis: anaerobic protozoan
Overgrowth due to change in acidity of vagina
Leukocytes accumulate at infection sites
Trichomoniasis symptoms
Irritation, itching, discharge (green yellow) with foul odour
Trichomoniasis diagnosis
microscopic examination of discharge
Gardnerella vaginalis
Gram variable rod
Overgrowth due to change in acidity of vagina
Discharge with fishy odour
Gardnerella vaginalis diagnosis and treatment
Diagnosis: microscopic examination of clue cells due to overgrowth of anaerobes
Treated with acetic acid gels/ introduction of lactobacilli
Metronidazole eradicates anaerobes preventing continuation of the disease
Herpes simplex
Initial infection is subclinical, recurrences occur to trauma, radiation, emotional upsets, hormonal changes
Genital herpes (HSV2)
Sexual contact transmission
Vesicles with burning sensation (vulva or base of penis)
Urination is painful
Walking is uncomfortable
Genital herpes treatment
None available, acyclovir a possibility
Genital herpes complication
Undetected leads to neonatal herpes via placental transfer, causing herpes encephalitis in babies
70% fatality
Genital wart
Papilloma virus causes mild skin growth
10% of GWs caused by serotypes that cause cancer
Genital wart treatment
Topical podofilax (podophyllum)
Lymphogranuloma veneruem
Tropical disease caused by chlamydia trachomatis
Massive inflammation of genital lymph nodes
Males: blockage of lymph vessels and enlargement of external genital
Female: rectal narrowing
Lymphogranuloma venereum diagnosis
Iodine staining of pus from infected lymph nodes
Chlamydial genital infection sex differences with age
a lot higher in females, even in young age, even higher inreproductive age
Chancroid (soft chancre)
Diseases of tropical areas (africa asia and latin america)
Caused by haemophilus ducreyi (gram negative rod)
Chancroid symptoms and treatment
Swollen painful ulcer on genitals with infection of lymph nodes
erythromycin
HIV type of virus
RNA (uses reverse transcriptase to convert RNA to DNA)
Describe structure of HIV virus
Envelope with spike proteins (antigenic), gp120 protein
Capsomere surrounding RNA and reverse transcriptase enzyme
How does HIV gain entry into T cells
gp120 on HIV binds to CD4 receptor on Th cell with aid of CXCR4 coreceptor on Th cell
HIV replication
HIV used reverse transcriptase to convert viral RNA to DNA inside Th cell, uses host machinery to make multiple copies of itself (RNA and envelope)
Buds off from Th cell as progeny
Or stays in macrophages(latent)
HIV transmission
Direct contact with infected body fluids (blood and semen)
Routes:
Intimate sexual contact, breast milk, trans placental, blood contaminated needles, organ transplants, blood transfusion)
In what region is HIV/AIDs most prevalent
Subsaharan africa, then southern and southeast asia
Describe the timeline of HIV infection in relation to T cell populations (8)
- Population of virus in blood peaks 1-2 months after infection
- populations of CD4 th cells depleted
- Seroconversion: antibodies against HIV appear in blood, HIV population declines
- HIV in blood population stabilises
- CD4 th cell population declines steadily
- Huge number of HIV generated by infected T cells
- Subclinical AIDS due to significant CD4 T cell depletion
- rise of HIV in blood as immune system breaks down
