UTIs Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Is bacteriuria pathological?

A

Bacteriuria = presence of bacteria in urine
Urethra is not sterile - as urine passes through organisms picked up
Bacteriuria is only treated in pregnancy and if symptomatic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What % women will experience symptomatic UTI in their lifetime?

A

40-50%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which organism predominantly causes UTIs?

A

E coli (95%) - specifically O1, O2, O4, O6, O7, O8, O75, O150 - have special p fimbriae to cling on

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Organism associated with UTI in young women

A

Staphylococcus saprophyticus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the three main defences against UTI?

A

3 Us - urine (low osmolality, low pH), urine flow and micturition, urinary tract mucosa (bactericidal, cytokines)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

3 organisms associated with UTI in complicated UTI

A

Complicated UTI = urinary tract structural/functional abnormality (e.g. catheter, stent, calculi)
P mirabalis, K aerogenes, E faecalis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Organism associated with in-dwelling catheters and prosthetics

A

S epidermidis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the mechanisms of UTI?

A

Most commonly ascending UTI (bacteria colonise urethra - ascend up urinary tract - multiply in bladder - can pass to ureters and kidneys)
Haematogenous spread from bacteraemia can occur - beware if S aureus in urine
Note: Bad MSU can be false positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What factors can make ascending UTI more likely?

A

Anything interfering with 3 Us - commonly obstruction stopping urine flow

  • Renal obstruction
  • Neurogenic malfunction
  • Vesicoureteral reflux (residual pool of urine in bladder after voiding can reflux up ureters)
  • Females - bacteria colonising warm, moist vulval area and short urinary tract
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does UTI present in different age groups?

A

Neonates, children <2: Non-specific (failure to thrive, vomiting, fever)
Children >2: More localised (frequency, accidents, dysuria)
Adult: Localised, dependent on upper or lower UTI
- Lower: LUTS (FUD)
- Upper: LUTS (FUD) + fever, flank pain
Old-age: Asymptomatic, confusion, ?non-specific

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

> 3 typical symptoms of UTI - Ix and Rx?

A
  1. Check for vaginal discharge to rule out STI

2. No urine dipstick needed - give empirical Abx treatment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

<2 typical symptoms of UTI - Ix and Rx?

A
  1. Check for vaginal discharge to rule out STI
  2. Obtain urine sample and check if cloudy - if not cloudy unlikely UTI - DON’T TREAT
  3. Urine dipstick - check nitrites + leucocytes (+ protein)
  4. a) Positive nitrites (+/- protein, leucocytes) = Probable UTI - TREAT
    b) Negative nitrite, protein and leucocyte - Unlikely UTI - DO NOT TREAT
    c) Negative nitrite, positive leucocyte - Treat if severe symptoms, send for MC+S
    d) Negative nitrite and leucocyte, positive protein - DO NOT TREAT
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

On urine dipstick, which parameter has the best positive predictive value?

A

Nitrites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

MC+S is not routine - when should it be used?

A
  • Urine dipstick negative for nitrites but positive leucocytes
  • Pregnancy
  • Suspected pyelonephritis
  • Complications (men, catheter, structural abnormalities)
  • Abx resistance (if UTI not responding)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is MC+S conducted?

A

M (microscopy - WCC triage)
C (culture to determine organism - chromogenic agar = pink E coli - takes 24h)
S (sensitivity - zones of inhibition analysed - further 24h)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What MC+S findings on microscopy support UTI?

A
  • > 10^4 colony forming units with urinary symptoms (>10^3 if E coli or S saprophyticus)
  • White cell triage - no culture if <10^4 white cells
17
Q

Sterile pyuria

A

Sterile pyuria = pus in urine but no organisms cultured

Consider non-culturable organisms e.g. TB, Chlamydia

18
Q

Why is it important to inform the lab if a patient is immunocompromised or pregnant?

A

White cell triage:

  • Pregnant - bacteriuria important regardless of WCC
  • Immunocompromised - low WCC may prevent culture from being performed
19
Q

Why is chromogenic agar used for culture in MC+S for UTI?

A

Urine is not sterile so non-causative organisms will also show up
Uses colour to indicate organisms present (e.g. E coli is pink)

20
Q

What does lots of squamous epithelial cells on microscopy indicate?

A

Bad MSU - only urethra lined by squamous, rest is columnar

21
Q

Uncomplicated lower UTI Tx

A

Cefalexin / trimethoprim / Nitrofurantoin
3 days if non-pregnant/breast-feeding female
7 days if male or pregnant/breast-feeding female

22
Q

Gram negative rod-shaped anaerobe

A

E coli

23
Q

Upper UTI Tx

A

IV co-amoxiclav + IV gentamicin for 1-2 days - oral switch in discussion with micro - treat for 14 days
If elderly, frail, risk of C difficile - IV gentamicin only (avoid co-amoxiclav)

24
Q

What is the treatment for UTI if a catheter is present?

A

IV gentamicin prior to catheter removal - only follow with treatment if systemically unwell

25
Q

Haemorrhagic cystitis in children

A

Adenovirus

26
Q

Dysuria + back pain
Blood in urine
Urine culture negative

A

Renal TB

27
Q

Walking / swimming in river Nile

A

Schistosomiasis of the blader

28
Q

Anatomically abnormal renal tract

Causative organism?

A

Klebsiella