Pathology of Urinary Tract Infection Flashcards

1
Q

What are some symptoms of UTI’s?

A
  • Dysuria (pain on micturition)
  • Frequency / polyuria
  • Foul smell of urine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are some UTI symptoms that are usually specific to very young people? The elderly?

A

Very young: unwell, failure to thrive

Elderly: incontinence, falls

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

In the normal urinary tract the ureters enter the bladder at an angle, how does this affect urine flow?

A

As the bladder fills up pressure from the urine is exerted on the bladder wall, and it closes off the ureter opening - preventing reflux on urine

(one way flow)

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

What are some of the bacteriostatic properties of urine? (properties stopping bac reproducing)

A
  • Low pH
  • High NH3 (ammonia) content
  • High osmolality
  • Antibacterial antibodies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe the level of sterility in the urinary tract

A
  • Terminal urethra not sterile (as urine exits)

- Rest of urinary tract is sterile

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

How do you collect a urine sample for culture when infection is suspected? Why?

A
  • Get the patient to void and then stop mid-stream, collect the next volume of urine
  • Done because initial void flushes out many terminal bacteria, so sample gives more accurate depiction of the bacteria actually infecting the urinary tract
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the sample of urine collected for culture called?

A

MSSU - mid-stream specimen of urine

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

In what cases will there be bacterial flora in the MSSU?

A

There will always be bacterial flora to be cultured

  • the concentration of bacteria detected is what determines whether there is an infection or not
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the methods for assessing the MSSU? Brief description?

A
  • Dip slide method (quick way): dip the slide into the urine and incubate at 37 degrees for 24h. Appearance of slide gives approx. [bacteria]
  • Formal microbiology culture
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What concentration of bacteria in the MSSU culture indicates infection?

A
  • 10^5 bacteria/mL

99% chance of infection even if asymptomatic

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

What concentration of bacteria in the MSSU culture suggests probable infection?

A

10^3 - 10^4 bacteria/mL

If symptomatic: probably infection. 50% chance of infection if asymptomatic

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

What concentration of bacteria in the MSSU culture suggests that there is no infection?

A

< 10^3 bacteria/mL

Usually suggests no infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are some issues with MSSU culture for UTI diagnosis?

A
  • Samples can be difficult to collect in young / elderly

- Some bacterial species are not part of urinary flora and may be pathogenic at low conc.

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

What micro-organisms are responsible for causing UTI’s?

A
  • Bacteria (gut flora - mostly e. coli)

- Viral infection (rare)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the most common route of infection when developing a UTI?

A
  • Almost always ascending, from urethra up to rest of urinary tract
  • Infection in kidneys has usually spread from bladder. Upper urinary tract infections are more serious
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does infection in the urinary tract cause in the tissues affected?

A

Inflammation

  • Urethra: urethritis
  • Bladder: cystitis
  • Ureter: ureteritis
  • Kidney: pyelonephritis (acute or chronic)
17
Q

What are the predisposing factors to UTI’s?

A
  1. Stasis of urine
  2. Pushing bacteria up urethra from below
  3. Generalized predisposition to infection (eg. diabetes, immunocompromised patients)
18
Q

What pathologies can cause stasis of urine?

A
  • Obstruction (slowed urine flow, can’t flush out bacteria = infection)
  • Loss of feeling of full bladder (brain / SC injury - don’t fully empty bladder, residual bacteria = infection)
19
Q

Where does obstruction tend to occur in the urinary tract? Consequences of each?

A
  • At level of urethra: causes bilateral hydroureter & bilateral hydronephrosis (swelling of ureters & kidneys)
  • At level of renal pelvis on 1 side only: unilateral hydroureter & hydronephrosis
20
Q

What can obstruction at the level of the ureter lead to?

A

Renal failure

Due to bilateral hydronephrosis

21
Q

In addition to risk of infection, what can obstruction of the urinary tract lead to?

A

Formation of calculi

Slowed urine flow - sediments form - calculous (stone) formation - more obstruction

Some types of urinary tract infections can predispose patients to calculi formation

22
Q

What is the most common congenital urinary tract abnormality that leads to obstruction and stasis of urine in children? Describe the pathophysiology

A
  • Vesicoureteric reflux
  • Decreased angle at which the ureters enter the bladder, meaning increased bladder pressure cannot properly close off the ureter opening, causing back-flow of urine that leads to hydroureter and hydronephrosis
23
Q

What are some common causes of urinary tract obstruction in adults?

A

Men: benign prostatic hyperplasia
Women: Uterine prolapse

Both: tumours and calculi

24
Q

How do neurological deficits that affect feelings of bladder fullness cause urinary tract infection?

A
  • Can’t sense when bladder is full / empty, results in partial emptying of full bladder: retention of some urine
  • This stasis of urine means all bacteria are not flushed out, leading to infections
25
Q

What are the main ways by which bacteria are pushed back up urethra from below?

A
  • Sexual activity in females

- Catheterization

26
Q

Which groups tend to be most at risk of developing UTIs?

A
  • Females

- The elderly

27
Q

What are some factors that predispose women to UTIs?

A
  • Short urethra
  • Lack of prostatic bacteriostatic secretion
  • Closeness of urethral orifice to rectum
  • Sexual activity (helps if void after intercourse)
  • Pregnancy (pressure on ureters and bladder)
28
Q

How does catheterization of the urinary tract lead to UTI’s?

A

Any instrumentation of urinary tract tends to move lower urethral flora up the tract

29
Q

What is the major acute complication associated with urinary tract infections?

A
  • Severe sepsis and septic shock
30
Q

What are some chronic complications of urinary tract infections?

A
  • Chronic kidney damage if repeated infections (pyelonephritis): hypertension & chronic renal failure
  • Calculi (kidney stones): hypertension & chronic renal failure