T11 - L5 Urinary Tract Infections Flashcards
what parts of the urinary tract are considered sterile and considered colonised?
sterile:
- kidney
- ureter
- bladder (usually)
colonised:
- urethra
what makes up the perineal flora?
skin flora
- mainly coagulase negative staphylococci
lower GI tract flora
- anaerobic bacteria
- aerobic bacteria e.g. enterbobacterales (coliforms) / gram positive cocci e.g. Enterococcus spp.
What is an Urinary Tract Infection?
- Cystitis (lower UTI)
- Pyelonephritis (upper UTI)
- Urethral syndrome
- significant bacteriuria
- asymptomatic bacteriuria
- sterile pyuria
what is the clinical term for a lower UTI?
cystitis
what is the clinical term for a upper UTI?
Pyelonephritis
what is pyuria?
the presence of pus in the urine, typically from bacterial infection.
what is bacteriuria?
the presence of bacteria in the urine.
what are symptoms of cystitis?
- Dysuria
- Frequency
- Urgency
- Supra-pubic pain or tenderness
- Polyuria, nocturia, haematuria
what is polyuria?
excessive or an abnormally large production or passage of urine (greater than 2.5 L or 3 L over 24 hours in adults). Frequent urination is usually an accompanying symptom.
what is nocturia?
wake up during the night because you have to urinate
what is pyelonephritis?
- Infection of the kidney and/or renal pelvis
- Symptoms of lower UTI
- Loin/abdominal pain or tenderness
- Fever
Other signs of systemic infection:
- Rigors, nausea, vomiting, diarrhoea
- Elevated CRP, WBC
what is urethral syndrome?
abacterial cystitis
symptoms of a lower UTI without demonstrable infection
what is the epidemiology of urethral syndrome?
30-50 year old women
what else can cause urethral symptoms as opposed to bacteria?
STIs
what is classed as “significant” bacteriuria?
> 105 cfu/mL = “significant” bacteriuria
104-105 cfu/mL = probable infection
what is asymptomatic bacteriuria?
no symptoms of a urinary tract infection
But cultured urine sample grows a single organism in significant numbers
what is “sterile pyuria”?
- pus cells in urine
- nor organisms grown
what are predisposing factors of UTIs?
- female sex -10:1 female:male ratio
- urinary stasis
- urological instrumentation
- sexual intercourse
- fistulae
- congenital abnormalities (VUR)
which congenital abnormality predisposes a patient to UTIs?
VUR
which type of fistulae predisposes a patient to UTIs?
Recto-vesical
vesico-vaginal
what may cause a UTI due to urinary stasis?
- pregnancy
- prostatic hypertrophy
- stones
- strictures
- neoplasia
- residual urine (poor bladder emptying)
what is a complicated UTI?
Underlying abnormality (structural / functional)
e. g.
1) Urinary stasis – obstruction / retention
2) Presence of “foreign body”
- Catheter / other device / renal calculi
- Biofilm
what is a uncomplicated UTI?
absence of underlying abnormality
absence of “foreign body”
what is an endogenous source of a UTI?
enteric flora (gut flora): - Perineum Movement of bacteria along a lumen - Fistulae Movement of bacteria from the genital/GI tract to the urinary tract
haematogenous spread (rare)
- Seeding of bacteria to the urinary tract via the blood
E.g Staphylococcus aureus
