Urinary Tract Infections Flashcards
1
Q
UTI definition
A
the inflammatory response of the urothelium to bacterial invasion
2
Q
UTIs are the result of
A
- reduced host defences
- micro-organism pathogenicity
usually a combination of these factors leads to the development of symptomatic infection
3
Q
Less common micro-organsims can result in UTI by two types of spread:
A
- haematonegenous spread
- direct transmission from adjacent infected
organs
4
Q
Less common micro-organsims can result in UTI by two types of spread:
A
- haematonegenous spread
- direct transmission from adjacent infected
organs
5
Q
UTIs can be broadly divided into (2):
A
- uncomplicated: occuring in a patient with a
structurally and functionally normal urinary
tract - complicated
6
Q
Bateriuria definition
A
presence of bacteria in the urine
7
Q
Pyuria
A
presence of white cells in the urine
8
Q
Sterile pyuria
A
presence of white cells in the urine with bacteriuria
9
Q
Asymptomatic bacteriuria definition
A
presence of bacteria on two consecutive urine cultures without symptoms of upper or lower UTI
10
Q
What is required for a UTI to be classed as a complicated UTI (2):
A
- positive urine culture with a risk factor
11
Q
Recurrent UTI (4):
A
- episode of UTI after documented
successful resolution of an earlier episode - frequency of at least twice in the previous
6 months - three times in the last 12 months
- classed as persistent or re-infection
12
Q
Persistent UTI:
A
- recurrent UTI caused by the same
organism - indicates focus of infection in the urinary
tract - stones/fistula
13
Q
Re-infection UTI:
A
- recurrent UTI caused by different
organisms - indicates susceptibility to UTI (genetic)
- associated with (3):
- poor hygiene
- sexual intercourse
- post-menopause
- 95% of female UTIs are due to re-infection
14
Q
Classification of UTI table
A
insert
15
Q
What % of females have one UTI in their lifetime?
A
50%
16
Q
What % of UTIs occur in men?
A
20%
17
Q
What % of elderly have asymptomatic bacteriuria?
A
20%
18
Q
Why are women more susceptible than men to UTIs?
A
- female urethra is shorter and straighter
- facilitates bacterial access to the bladder
19
Q
In postmenopausal women, what may predispose patients to UTIs?
A
- oestregne deficiency
- from increased colonisation with E.coli
20
Q
In men, UTI is often associated with
A
urinary obstruction eg bladder outlet obstruction due to prostate enlargement
21
Q
Use of what type of catheters can cause UTIs
A
- indwelling catheters (men and women)
22
Q
Male urethra
A
insert image
23
Q
3 risk factors of uncomplicated UTIs:
A
- female gender
- older
- younger
24
Q
Risk factors of complicated UTIs?
A
- indwelling catheters
-immunosuppression - urinary tract abnormalities
- antibiotic exposure
25
Aetiology of UTI:
- UPEC
- K. pneumoniae
- S. saprophycticus
- Candida
- S. aureus
26
UTIs: Anatomical Sites (6):
insert slide
27
Classification of UTIs
insert
28
Risk factors for complicated UTIs:
insert
29
Acute Cystitis
- the infection and inflammation of
the bladder urothelium
- often associated with lower urinary
tract symptoms: dysuria, frequency,
urgency, suprapubic pain, offensive
urine
- if dysuria and frequency are both
present then probability of UTI >90
and EMPIRICAL antibiotic treatment
indicated
30
Acute Pyelonephritis
- infection/inflamm of kidney
- symptoms: flank pain, nausea,
vomiting and pyrexia
- must differentiate early between
acute, uncomplicated and
obstructive (stone from kidney to
ureter, backpressure causes this,
antibiotics won't help)
- can result in urosepsis
- imaging of upper urinary tract key
for evaluating obstruction or renal
stones
31
Catheter associated UTI:
- catheters provide a focus for
bacterial biofilm formation
- long0term indwelling catheters
often colonised with two or more
organisms
32
When is antibiotic treatment indicated in patients with catheter associated UTI?
- only if symptomatic
33
Epididymo-orchitis
- inflammation of the epididymis and
or testicle
- causes pain, swelling and often
unilateral
- antimicrobials selected empirically
that in young, sexually active men
c. trachomatis is usually causative
- in older men with BPH or other
micturition disturbances, generally
gram neg e-coli
34
Pathogenesis of UTIs:
- faecal flora (gram neg) colonise
perineum, UTI usually results from
retrograde ascent of these
microorganisms
- bacteria adhere to the urothelium
and release toxins
35
UTI: UPEC: Pathogenesis:
insert slidess
36
Clinical Presentation of UTI: Mneumonic:
FUND
37
Clinical Presentation of UTI: FUND:
- frequency
- urgency
- nocturia
- dysuria
- foul odour
- suprapubic pain/tenderness
indicative of cystitis
- costovertebral angle
pain/tenderness indicative of
pyelonephritis
- Fever
- hypotension and altered mental
state may indicate sepsis
38
Clinical Presentation of Pyelonephritis:
- fevers, rigors, loin pain
- renal angle tenderness
- costovertebral angle pain
- if pain radiates to groin = stone
- risk of bacteraemia
39
UTI Investigations:
- urine dipstick
- microscopy
- urine culture
- renal imaging
40
UTI Investigations: Urine Dipstick:
- urinary pH: alkaline may indicate a
urea-splitting organism
- leukocyte esterase: inflammatory
cells
- nitrite: enterobacteria family
- blood: cystitis may cause but
malignancy should be ruled
out
- protein: glomerulopathy, large WBC
count may lead to a false
positive
41
If a urine dipstick shows presence of nitrites but not leukocytes then
does not necessarily suggest a UTI
42
UTI Investigations: Microscopy:
- midstream sample
- centriguged
- more 5 leukocytes per high power
field denotes pyruria
- sterile pyuria may occur with:
- bacterial infections (renal
abscesses)
- partially treated UTI
43
UTI Investigations: Urine Culture:
- gold standard investigations
- 0.1 ml urine delivered onto each half
of split agar plate
- number of colonies estimated after
overnight incubation
- more than 10to the power 5 colony
count for diagnosing UTI
- 50% symptomatic women have a
lower colony count
- 100 colonies may signal infection in
symptomatic patients
44
Urinary bacteria generally gram positive or negative?
Gram negative
45
Gram staining:
Pink signifies
Purple signifies
pink = gram neg
purple = gram pos
46
Is E.coli gram positive or negative?
Negative
47
Gram positive organisms include:
- enterococcus faecalis
- staphylococcus
48
UTI Investigations: Renal Imaging:
- ultrasound
- CT
- in pts who are systemically ill, with a
history of kidney stones
- to rule out an infection behind an
obstruction that mimics an abscess
49
Uncomplicated cystitis: Management: Women:
- empiric treatment in healthy, non-
pregnant women with classic
symptoms of acute UTI without
evidence of pyelonephritis
- urinary dipstick is only test required
- if abnormal then pelvic exam and
urine culture could be indicated
50
Uncomplicated Cystitis: Management: Men:
- urine dipstick and culture generally
performed before therapy
51
Uncomplicated Pyelonephritis: Management:
- urinary dipstick is usually positive
- urine culture sent for definitive
diagnosis, to find causative
organism
52
Complicated UTI: Management:
- suspected in pts who relapse and
don't improve with therapy
- results when anatomic or functional
abnormality of urinary tract or a
resistant infection
- cather associated UTI always
complicated
- urine culture recommended
53
Asymptomatic Bacteriuria: Management:
- screening for asymptomatic
bacteruria unnecessary
- pregnant women screened and
treated if bacteria count 10,000 or
more to decrease risk of
pyelonephritis
- patients undergoing renal or
urologic procedures also benefit
from screening
54
UTI: Antibiotic Treatment:
- empiric: consider target organisms,
route of administration, side effects,
resistance
- uncomplicated UTI usually need 5
days antibiotics (broad-spectrum)
whilst waiting for culture
55
UTI Treatment: Antibiotics: Empiric Drugs:
- nitrofurantoin (4x day)
- trimethoprim (x2 day)
- 5-7 days for trimethoprim
56
Prevention of recurrent UTIs:
- correct underlying host cause
(diabetes mellitus)
- antibiotic prophylaxis (temporary)
- behavioural changes:
- high fluid intake
- void after intercourse
- double voiding (before and
after)
- OTC: cranberry juice
- oestregen replacement for post
menopausal women
57
Prevention of Catheter Acquired UTIs:
- only use for a good reason
- asceptic insertion
- closed drainage system
- remove promptly when no longer
indicated
