Urinary Tract Infections

Question 1

What is the presentation of UTI?

Answer 1

Dysuria (pain on micturition)

Frequency

Smelly urine

Very young - failure to thrive

Very old - incontinnce, off their feet

Question 2

What percentage of cardiac output is renal blood flow?

Answer 2

20 - 25%

Question 3

How does urine change with oral intake of fluids?

Answer 3

Resorption of fluid is diminished if increase fluid intake therefore increased urine output

Question 4

How do ureters function?

Answer 4

They have continuous trickle of urine - they do not store urine

Question 5

How do the ureters interact with the bladder wall?

Answer 5

Ureters enter the bladder at an angle

Increasing pressure from the bladder as it fills closes off the ureter and stops the reflux of urine

Question 6

What is the content of normal urine?

Answer 6

•Low pH, high osmolality, and high ammonia (NH3) content of normal urine

Question 7

What is a useful property of prostatic secretions?

Answer 7

They are bacteriostatic

Question 8

What portions of the normal renal tract are sterile?

Answer 8

All except the terminal urethra

Suprapubic aspirate of urine is sterile

Question 9

What part of the stream do we use for urine specimen?

Answer 9

Mid stream

Initial voiding will flush out many terminal urethral floral bacteria

Mid stream specimen - urethral flora is diminished but always present - will always grow on culture - never a negative result

Question 10

•MSSU – how to tell contamination from real infection?

Answer 10

Send to microbiology for culture under set conditions - bacterial multiply in log phase growth

10⁵ is usually an infection - unless contamination (chances of which are less than 1 in 100)

Contamination more likely if they are asymptomatic

Question 11

What values are associated with infection ‘sometimes’?

Answer 11

10³ or 10⁴

Probably an infection if there is symptoms

50% chance if there is no symptoms

Question 12

When is there usually no infection?

Answer 12

When the culture shows less than 10³

Question 13

What is a problem associated with MSSU culture interpretation?

Answer 13

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

Question 14

What are the micro-organisms that cause UTI?

Answer 14

• Bacteria mostly = gut flora, especially E.coli
• Viral infection rare

Question 15

What is the route of infection in UTI?

Answer 15

Almost always ascending

If kidneys are infected this is usually because infection in the kidneys has usually spread up from the bladder infection

Upper UTI’s are more serious

Question 16

What is the neame given to inflammation of the urethra, bladder ureter and the kidney?

Answer 16

• Urethra – urethritis
• Bladder – cystitis
• Ureter – ureteritis
• Kidney – acute pyelonephritis / chronic pyelonephritis

Question 17

What are the predisposing factors to UTI?

Answer 17

Stasis of urine

Pushing bacteria up the urethra from below

Generalised predisposition

Question 18

What are the causes of stasis of urine?

Answer 18

Obstruction

Loss of feeling of a full bladder - spinal cord / brain injury

Question 19

What are the causes of pushing bacteria up from the urethra below?

Answer 19

Sexual activity

Catheterisation (and other urological procedures)

Question 20

What is a generalised predisposition to infection?

Answer 20

Diabetes

Question 21

Why does stasis of urine cause UTI?

Answer 21

•Bacteria that do get higher up do not get flushed out

Question 22

What happens when there is obstruction at the level of the urethra?

Answer 22

Upper urethral and bladder dilation

Bilateral hydroureter

Bilateral hydronephrosis - chronic renal failure

Question 23

What happens when there is obstruction of the renal pelvis on one side only?

Answer 23

Causes unilateral hydroureter and unilateral hydronephrosis

Question 24

What are consequences of obstruction?

Answer 24

Proximal dilateion

Slowed urine flow - cannot flush out bacterial - infection

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

Calculous - more dilation, increased calculous formation, more infections

Question 25

What is a common cause of obstruction in children?

Answer 25

Vesicoureteric reflux - decreased angulation at angle into the bladder

Question 26

What are common causes of obstruction in adults?

Answer 26

•Men – Benign Prostatic Hyperplasia (not a tumour) of prostate – functional and anatomical obstruction

Women - uterine prolapse

Both sexes - tumours and calculi

Question 27

How does spinal cord/brain injury predispose to UTI?

Answer 27

•Decreased sensation therefore 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 28

How does sexual activity in females predispose to UTI?

Answer 28

Tends to move lower urethral flora up the tract (back wall of urethra is just in front of the vagina)

Question 29

What are the predisposing factors that increase chances of getting a UTI in female sexual activity?

Answer 29

• 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 30

What is the effect of catheterisation on the urethral flora?

Answer 30

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

Question 31

What parts of diabetes cause you to be more predisposed to infection?

Answer 31

Glucose in urine

Poor function of WBC

Question 32

Summary of when people get UTI’s

Answer 32

Question 33

What is an acute complication of UTI?

Answer 33

Severe sepsis and septic shock

Question 34

What are chronic complications of UTI?

Answer 34

• Chronic damage to kidneys if repeated infections (chronic pyelonephritis) therefore hypertension, chronic renal failure
• Calculi - obstruction- Hydronephrosis - hypertension, chronic renal failure