UTI Flashcards
Which groups are most affected by UTIs
women all ages, old men and infant boys
example of an uncomplicated lower UTI, and an uncomplicated upper UTI
Cystitis
acute pyelonephritis
Most common organism causing UTI
UPEC: uropathogenic Escherichia coli
Host factors causing lower UTI
Host factors causing upper UTI
> obstruction (prostatic hypertrophy, urethral stricture)
poor bladder emptying eg bladder diverticula
catheterisation
vesico-enteric fistula
sex
diabetes
> May follow from lower UTI
vesico-enteric reflux
obstruction eg calculus (Stone), stricture
describe the pathogenesis of a UTI from contamination of periurethral area to bacteraemia
1) contamination of periurethral area with a uropathogen from the gut
2) colonization of urethra/ migration to bladder
3) colonization of bladder and invasion of bladder, mediated by pili and adhesins
4) neutrophil infiltration
5) bacterial multiplication and immune system subversion
6) biofilm formation
7) epithelial damage by bacterial toxins
8) ascension to kidneys
9) colonization of kidneys
10) host tissue damage by bacterial infection
11) bacteraemia
pathogenesis - bacterial virulence depends on what 3 factors
adherence, invasion, evasion
describe adherence of UPEC in pathogenesis of UTI
In bladder, UPEC express type 1 pili which is essential for colonization, invasion and persistence. UPEC are highly adhesive which aids in retrograde ureteral ascent.
signs which lead to cystitis as likely diagnosis
bladder and urethral symptoms
overlap with urethritis
dysuria, frequency, urgency, suprapubic pain, nocturia
smelly/cloudy urine/visible blood
children/elderly/catheterised
signs which lead to pyelonephritis as likely diagnosis
fever/rigors/loin pain renal angle tenderness lower UTI symptoms in addition common of pain radiation to groin could be stone risk of bacteraemia
how can we use dipstick test to help diagnose UTI
not diagnostic alone
look for presence of nitrates and/or leukocytes
if nitrites positive with symptoms suggests cystitis, treat
don’t need to send urine for culture in simple cystitis in a non-pregnant adult female
under what conditions do we send urine sample to be cultured
why do we use mid-steam urine (MSU)
pregnant, children and men, pyelonephritis suspected, recurrence, failed treatment, renal impairment, abnormal urinary tract
minimise urethral contamination
how to prevent UTI
correct any underlying host causes eg uncontrolled DM
antibiotic prophylaxis (temp between 6months to 2 yrs)
behavioural changes eg high fluid intake, void after sex
how to prevent catheter acquired UTIs
use only for good reason (eg measurement of urine output in acutely unwell, measure acute retention and obstruction, selected surgeries)
aseptic insertion
closed drainage system
remove promptly as soon as no longer needed
under what condition would we treat asymptomatic bacteriuria
pregnant
