Pathology of UTI

Question 1

How do UTIs usually present?

Answer 1

• Dysuria
• Frequency
• Smelly urine

Question 2

Dysuria

Answer 2

Pain on micturition

Question 3

How can a UTI present in the very young?

Answer 3

• Unwell

- Failure to thrive

Question 4

How can a UTI present in the elderly?

Answer 4

• Incontinence

- Off their feet

Question 5

What percentage of CO accounts for renal blood flow?

Answer 5

20-25%

Question 6

What does urine output change with in the normal renal tract?

Answer 6

Oral intake of fluids

Question 7

Why is there reduced resorption of fluid if theirs increased fluid intake?

Answer 7

There is increased urine output

Question 8

How does urine from the kidneys reach the bladder?

Answer 8

There is a continuous trickle of urine through the ureters

Question 9

How do the ureters enter the bladder?

Answer 9

At an angle

Question 10

How is reflux of urine up the ureters prevented?

Answer 10

Increasing pressure from the filling bladder closes off the ureter/

Question 11

What are the bacteriostatic properties of the normal urinary tract?

Answer 11

Free flow of urine through normal anatomy (assumes drinking enough fluids)

• Low pH, high osmolality, and high ammonia (NH3) content of normal urine
• Prostatic secretions are bacteriostatic
• Anti-bacterial antibodies

Question 12

What parts of the urinary tract are sterile?

Answer 12

All of the urinary tract apart from the terminal urethra

Question 13

Why is the terminal urethra not sterile?

Answer 13

Skin (perineal) and gut (rectal) flora means it is not sterile

Question 14

What type of aspirate would be sterile?

Answer 14

Suprapubic

Question 15

What is urinated specimen always contaminated by?

Answer 15

Urethral flora

Question 16

What will initial voiding do?

Answer 16

Flush out many terminal urethral flora bacteria

Question 17

How should urine for culture be collected?

Answer 17

MSSU

-Patient voids and stops mid-stream, discarding urine, then collects next volume of urine

Question 18

What does MSSU stand for?

Answer 18

Mid stream specimen urine

Question 19

What is always present in MSSU?

Answer 19

Urethral flora but it is diminished

Question 20

What will always grow in culture?

Answer 20

Urethral flora

Question 21

How can contamination be differentiated from real infection in MSSU culture?

Answer 21

Cultured under set conditions and bacteria multiply in log phase growth

• 10^5 usually infection
• 10^3> 10^4 sometimes infection, probable if symptomatic (50% chance if no symptoms)
• <10^3 usually no infection

Question 22

Who is it difficult to collect MSSU from?

Answer 22

Young children and the elderly

Question 23

What problems are there with interpreting urine culture?

Answer 23

Some bacterial species are not normally present in terminal urethra/rectal flora and may be pathogenic at low colony numbers

Question 24

What organisms cause UTIs?

Answer 24

• Bacteria mostly gut flora and especially E coli

- Viral infections are rare

Question 25

What is the route of infection almost always?

Answer 25

Ascending

Question 26

Where have kidney infections usually spread from?

Answer 26

Bladder

Question 27

Infection of what part of the urinary tract is more serious?

Answer 27

Upper urinary tract

Question 28

What is inflammation of the urethra called?

Answer 28

Urethritis

Question 29

What is inflammation of the bladder called?

Answer 29

Cystitis

Question 30

What is inflammation of the ureters called/?

Answer 30

Ureteritis

Question 31

What is inflammation of the kidney called?

Answer 31

Acute pyelonephritis

Question 32

What is inflammation of the kidneys called if there is recurrent/prolonged infection?

Answer 32

Chronic pyelonephritis

Question 33

What does infection lead to?

Answer 33

Inflammatory response

Question 34

What are the predisposing factors fro UTI?

Answer 34

- Stasis of urine - Pushing bacteria up urethra from below - Generalised predisposition to infection

Question 35

What can cause stasis of urine?

Answer 35

- Obstruction, whether congenital (presents in childhood) or acquired (adults). - Spinal cord/brain injury, loss of ‘feeling’ of full bladder -

Question 36

What can cause bacteria to be pushed up the urethra from below?

Answer 36

- Sexual activity in females | - Catheterisation (and other urological procedures)

Question 37

Give an examples of a generalised predisposition to infection.

Answer 37

Diabetes mellitus

Question 38

Why can stasis of urine cause UTI?

Answer 38

Bacteria that do get higher up do not get flushed out

Question 39

What does obstruction at the level of the urethra lead to?

Answer 39

- Upper urethral and bladder dilatation - Bilateral hydroureter - Bilateral hydronephrosis leading to chronic renal failure

Question 40

What can obstruction of the renal pelvis unilaterally cause?

Answer 40

- Unilateral hydroureter | - Unilateral hydronephrosis

Question 41

What are the consequences of obstruction?

Answer 41

- Proximal dilatation - Slowed urine which cannot flush out bacteria leading to infection - Slowed urine flow leading to sediment formation can calculous (stone) formation causing obstruction

Question 42

What can some bacterial infections predispose to?

Answer 42

Calculous formation

Question 43

What is the triad of the consequence of obstruction?

Answer 43

- Infection - Calculi - Obstruction

Question 44

When should children be investigated?

Answer 44

Always investigate at 1st presentation and send to paediatric surgeons as there are numerous renal tract abnormalities

Question 45

What is the most important renal tract abnormality?

Answer 45

Vesicoureteric reflux

Question 46

What causes Vesicoureteric reflex?

Answer 46

Decreased angulation of the ureter when entering the bladder

Question 47

What does Vesicoureteric reflux cause?

Answer 47

Hydroureter

Question 48

What is a common cause of obstruction in men?

Answer 48

Benign prostatic hyperplasia (not a tumour) of prostate. It is a functional and anatomical obstruction

Question 49

What is a common cause of obstruction in women?

Answer 49

Uterine prolapse

Question 50

What are common causes of obstruction in adult males and females?

Answer 50

- Tumours | - Calculi

Question 51

How does spinal cord/brain injury lead to stasis of urine?

Answer 51

- Decreased sensation - No sense of when to micturate and do not know to empty bladder completely - Leave urine in bladder (high residual volume) - Stasis of urine

Question 52

Why does sexual activity lead to UTI in females?

Answer 52

In females sexual activity tends to move lower urethral flora up the tract (back wall of urethra is just in front of vagina)

Question 53

Why do females of any age have a predisposition to UTIs?

Answer 53

- 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

Question 54

What can instrumentation of the urinary tract do?

Answer 54

Move lower urethral flora up the tract

Question 55

Why are diabetic more likely to get UTIs?

Answer 55

- Glucose in urine | - Poor function of WBC

Question 56

What is the most common cause of UTIs in the early years?

Answer 56

Congenital abnormalities

Question 57

What is the most common cause of UTI in teenage and young females?

Answer 57

Sexual activity

Question 58

What is the most common causes of UTI in older adults?

Answer 58

- Men: prostate problems - Women: uterine prolapse - Both sexes: Tumours

Question 59

What is an acute complication of UTI?

Answer 59

Severe sepsis and septic shock

Question 60

What are chronic complications of UTI?

Answer 60

- Chronic damage to kidneys if repeated infections (chronic pyelonephritis) leading to hypertension and chronic renal failure - Calculi can cause obstruction and hydronephrosis which can result in hypertension and chronic renal failure

Question 61

What is the key question in UTI?

Answer 61

Why has the patient presented now?