Infection of the GU tract Flashcards
What is affected in:
- upper UTI
- lower UTI?
Upper: renal pelvis, ureters
Lower: bladder, urethra, prostate, testes
What is pyelonephritis?
Inflammation caused by infection of the renal pelvis of the kidney
What is urethritis?
Inflammation caused by infection of the urethra
What is cystitis?
Inflammation caused by infection of the bladder
What is prostatitis?
Inflammation caused by infection of the prostate?
What is ureteritis?
Inflammation caused by infection of the ureter(s)
What is epididymitis?
Inflammation caused by infection of the epididymis
What is orchitis?
Inflammation caused by infection of the testicle(s)
What is bacteriuria?
Presence of bacteria in the urine which can be asymptomatic or symptomatic
What is pyuria?
Presence of leucocytes in the urine
Can be sterile or asterile
How do you classify UTIs (aside from by their location)?
Complicated or uncomplicated
What defines a UTI as complicated?
If they are:
- male
- pregnant
- a child
- immunocompromised
If there is:
- recurrent / persistent infection
- nosocomial infection
- a known abnormality in GU tract
- SIRS or sepsis
- GU disease (stones, fistula)
What is meant by a ‘nosocomial infection’?
A hospital acquired infection
Which type of bacteria are usually responsible for UTIs?
Gram -ve or gram +ve
Cocci or bacilli
Usually gram negative bacilli
Such as E. coli
Which bacteria is most commonly the cause of UTIs?
E. coli
Name some pathogens that cause UTIs?
E. coli Staphylococci species Enterococci species Klebsiella species Proteus mirabilis
How are E. coli specialised to infect the GU tract?
Fimbriae: to help them latch onto epithelium
Pili: bacterial conjugation
Acid polysaccharide coat that resists phagocytosis
What receptors do the fimbriae of E. coli attach to on uroepithelium?
Mannose receptors
Why does oestrogen depletion increase the risk of developing UTIs?
Normally the vagina is colonised with lactobacilli
These maintain a low pH in the vagina
Less oestrogen = fewer lactobacilli
Fewer lactobacilli means higher pH so pathogens can colonise more easily
Also commensals are unable to survive
What is the purpose of the acid polysaccharide coat found on E. coli?
It makes them resistant to phagocytosis
What is special about the Proteus species?
They are able to produce urease
Urease breaks urea into CO2 and ammonia
Ammonia raises the pH of the area, meaning it’s more hospitable for bacteria
And stones are more likely to form: ammonium staghorn stones
What does urease do?
Breaks urea into CO2 and ammonia
What host defence mechanisms do we have to prevent UTI?
Urine flushes tubes as it flows through
Tamm-Horsfal protein
Glycosaminoglycan layer
Low urine pH and high concentration
Commensal flora
What does Tamm-Horsfal protein do?
Bacteria with mannose sensitive fimbriae (E. coli) are trapped by THP
THP has mannose containing chains that trap bacteria
What does the glycosaminoglycan (GAG) layer do?
Its a layer on the bladder wall that protects it by preventing bacteria in the urine gaining access to bladder wall
How do commensal bacteria in the GU tract prevent UTI?
Presence of commensals prevents infection because the vagina (for example) is already colonised, there’s no room for the pathogen
So it can’t migrate to urinary tract
What can disrupt commensal bacteria, leaving the urothelium susceptible to infection?
Spermicides
- used as a form of contraceptive
- they also damage commensals
Low oestrogen levels:
- fewer lactobacilli (a normal commensal)
Antibiotics:
- can kill commensal as well
What two types of bacteriuria are there?
Pathogenic: only one type of bacteria
Contaminant: lots of types, mixed growth
You should always treat bacteriuria.
True or false?
False, often it is aymptomatic and causes no harm
Only treat in pregnancy
Why should you treat bacteriuria in pregnancy?
Pregnant women have a higher chance of getting pyelonephritis
Also increased risk of pre-term labour
Who gets bacteriuria?
Increased prevalence with age
More common in institutionalised (in care homes etc.)
100% of catheterised patients will have bacteriuria
What are the risk factors of UTI?
Being female
Immunosuppression
Pregnancy
Menopause
Sexual intercourse
Use of spermicides
Stones
Catheter
Why are females more susceptible to UTIs than males?
They have a shorter urinary tract
Proximity of urethral meatus to entrance of vagina and anus
Why is it vital to do a urine dipstick test on pregnant women?
Because if they have bacteriuria they have a high risk of developing complications like pyelonephritis or pre-term labour
Often bacteriuria is asymptomatic until a complication has developed, by then it is too late
Why does menopause increase the risk of UTI?
Menopause = less oestrogen
Less oestrogen = fewer lactobacilli in vagina = higher pH
Higher pH = more pathogenic bacteria colonise
Spread from vagina to urethra
Clinical features of pyelonephritis?
High fever Rigors Vomiting Loin pain and tenderness Oliguria
Clinical features of cystitis?
Dysruria: painful or difficult urination
Increased frequency and urgency
Haematuria
Cloudy, offensive smelling urine
Investigation of a UTI?
Mid-stream urine sample:
- culture, microscopy, sensitivity
- look for pyuria
Bloods if suspecting urosepsis
USS + Cystoscopy: look for stones, abscesses
What are the problems with mis-stream urine samples?
High rates of contamination when the urine leaves the body
Contamination from vulva, penis
Getting a mid-stream urine sample from children is difficult. How can you solve this problem?
Do a clean catch urine sample
Needle into suprapubic area into bladder to get a fresh sample of urine
Treatment of a UTI?
Antibiotics: nitrofurantoin, trimethoprim
3 days for women, 7 for men
Pregnant women don’t give trimethoprim
Children, nitro, trimeth or amoxicillin
Increase fluid intake
Void pre and post intercourse
Keep good hygiene
Don’t use spermicides
When prescribing a woman with antibiotics what do you need to advise?
Antibiotics can make the oral contraceptive pill less effective
Use another form of contraceptive
Do you need to do an MSU sample in all cases of UTI?
No, only in complicated cases
What causes recurrent UTIs?
Re-infection with same bacteria
Bacterial persistence
Unresolved infection:
- poor compliance with treatment
- resistant organism
Investigation of recurrent UTIs?
MSU
Digital rectal and vaginal examination
Post void bladder scan
USS or renal tract
X-ray to look for stones
Cystoscopy
Prevention of UTIs?
Drink plenty of fluids
Antibiotic prophylaxis:
- post coital
- continuously
Self start treatment: when feel UTI starting
Cranberry (not much effect at low concentrations)
What causes a UTI to develop into urosepsis?
Very virulent / resistant organism
Immunosuppression
Raised pressure in the urinary tract
What is urosepsis?
Sepsis that has been caused by a UTI
What causes raised pressure in the urinary tract?
Obstruction of tract:
- stone
- tumour
Poor bladder emptying
Catheterisation
How do you manage urosepsis?
ABCDE
BUFALO
Which age group is most susceptible to prostatitis?
Men below 50
Clinical features of prostatitis?
Flu-like symptoms
Lower backache
Problems with urination
Pain post ejaculation and erection
Tender, boggy prostate
Investigation of prostatitis?
Urinalysis, MSU
Semen cultures
Blood cultures
STI screen
USS, CT of abdomen + pelvis
What usually causes urethritis?
STIs
What is Epididymo-orchitis?
Inflammation of testicle and epididymis
Caused by infection
What should you consider when faced with a patient with epididymo-orchitis?
Testicular torsion!
Clinical features of Epididymo-orchitis?
Swollen, tender, warm testes
Pain on urination
Fever
Malaise
Investigation of pyelonephritis?
Males: rectal exam to rule out prostatitis
Females: vaginal exam to rule out ovarian pathologies
Rule out appendicitis
Blood cultures
USS: to look for obstruction
Management of pyelonephritis?
Antibiotics IV: ciprofloxacin, co-amoxiclav
Treat any obstructions
Catheterise
Analgesia
What complications can arise from pyelonephritis?
Renal abscess
Emphysematous pyelonephritis
Long term renal damage
What is Emphysematous pyelonephritis?
Involves gas forming organisms
Very serious
May involve emergency nephrotomy
What’s the mnemonic for UTIs…
WET
Women
E. coli
Trimethoprim
