Pathology of UTIs

Question 1

UTI presentation?

Answer 1

Dysuria
Frequency
Urine will smell

In elderly - incontinence, delirium

In very young - unwell, failure to thrive

Question 2

How much of CO is renal blood flow?

Answer 2

20-25%

Question 3

Do ureters store urine?

Answer 3

No - they have a continuous trickle of urine

Question 4

Ureters enter the bladder at a BLANK this is significant because?

Answer 4

Angle

Significant as when bladder fills, the pressure inside closes off the ureter and stops reflux of urine

Question 5

Normal urine pH, osmolality and ammonia contents ?

Answer 5

Low pH
High osmolality
High ammonia

Question 6

Prostatic secretions are…which means…

Answer 6

Bacteriostatic - biological or chemical agent that stops bacteria from reproducing

Question 7

Does urine contain anti-bacterial antibodies?

Answer 7

Yeah

Question 8

Is the urinary tract ALL sterile?

Answer 8

No - most is except the terminal urethra

Question 9

What significance does the terminal urethra not being sterile have on urine sample collection?

Answer 9

Sample must be collected mid-flow as the initial flow will be contaminated with the terminal urethra’s bacteria

The initial flow diminishes the urethras bacteria, doesn’t eliminate it

Question 10

What is a MSSU?

Answer 10

mid stream specimen of urine

Question 11

How do we tell if a MSSU is contaminated or if there is a real infection?

Answer 11

Sent to microbiology for culture under set conditions

Bacteria multiply in a log phase growth

Question 12

What is a faster way to read a MSSU and to determine if it is contamination or infection?

Answer 12

A dip slide method - incubated for 24 hours at 37 degrees

A culture reading of 10^5 usually indicates infection

10^3 or ^4 suggests an infection probable if symptoms but if NO symptoms a 50% chance it isn’t an infection

Question 13

If the culture shows less than 10^3?

Answer 13

Won’t be an infection

Question 14

Issues with MSSU?

Answer 14

Hard to collect in young and elderly

Some bacteria are not normally preent in terminal urethra/rectal flora and may be pathogenic at low numbers BUT won’t be picked up on with a dip slide method

Question 15

Microorganisms that cause UTIs?

Answer 15

Bacteria - usually gut flora - like E.coli

Viral infection rare

Question 16

Route of infection?

Answer 16

Almost always ascending

An infection in the kidney’s would have spread from a bladder infection

Question 17

Is an upper or lower UTI more serious?

Answer 17

Upper

Question 18

Infection in urethra, bladder, ureter and kidney are called what respectively?

Answer 18

Urethra - urethritis
Bladder - cystitis
Ureter - ureteritis
Kidney - acute pyelo-nephritis BUT if prolonged - chronic pyelonephritis

Question 19

What are the predisposing factors for a UTI?

Answer 19

1. Stasis of urine
2. Pushing bacteria up from urethra below
3. Generalised predisposition to infection

Question 20

What can cause stasis of urine?

Answer 20

Obstruction - congenital or acquired

Spinal cord/brain injury - losing the feeling of a full bladder

Question 21

Why does stasis of urine cause a UTI?

Answer 21

Bacteria that get higher up in the tract are not flushed out

Question 22

What does obstruction at the level of the ureter cause?

Answer 22

Upper urethral and bladder dilatation eventually leading to bilateral hydroureter

Question 23

What can bilateral hydroureter lead to?

Answer 23

Bilateral hydronephrosis (swelling of kidney) leading to chronic renal failure

Question 24

What happens if obstruction is at level of renal pelvis?

Answer 24

Unilateral hydroureter (lower ureter will be fine) and unilateral hydronephrosis

Question 25

Consequences of obstruction?

Answer 25

Proximal dilatation Low urine flow means bacteria isn't flushed out = infection Low urine flow also means sediments form leading to calculous formation and further obstruction = further infections

Question 26

What should be done if a child presents with obstruction?

Answer 26

Always investigate asap and send to paediatric surgeons

Question 27

Most important obstruction cause in kids?

Answer 27

Vesicoureteric reflux - when angle of ureters into bladder is decreased and = a hydroureter

Question 28

Common causes of obstruction in men?

Answer 28

Benign prostatic hyperplasia (not a tumour) Is a functional and anatomical obstruction

Question 29

Common causes of obstruction in women?

Answer 29

Uterine prolapse

Question 30

Common causes of obstruction not specific to 1 sex?

Answer 30

Tumours and calculi

Question 31

Why does a spinal injury that reduced sensation of when bladder is full cause stasis of urine

Answer 31

No sense of when to micturate and do not know how to empty bladder fully and leave urine in bladder = stasis of urine

Question 32

What can cause bacteria to be pushed up the urinary tract?

Answer 32

Sexual activity in women | Catheterisation

Question 33

Who would have a generalised predisposition to infection?

Answer 33

Diabetics due to glucose in urine and poor function of WBCs

Question 34

Acute complications of UTIs?

Answer 34

Sepsis and septic shock

Question 35

Chronic complications of UTIs?

Answer 35

Chronic damage to kidneys if repeated infections Calculi = obstruction = hydronephrosis All this leads to hypertension and chronic renal failure