Urinary tract infection pathology

Question 1

what is the presentation of a uti?

Answer 1

dysuria
frequency
smelly urine

Question 2

why would a uti occur in yound children versus an eldery patient?

Answer 2

young - unwell failure to thrive

old - incontinent

Question 3

renal blood flow is what percent of cardiac output?

Answer 3

20-25% of cardiac output

Question 4

does urine output change with oral intake of fluid?

Answer 4

yes resorption of fluid is diminished if increase fluid intake increased urine output

Question 5

do ureters store urine?

Answer 5

no have a continuous trickle of urine

Question 6

how to ureters enter the bladder?

Answer 6

at an angle

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

Question 7

what are bacteriostatic properties od the urinary tract?

Answer 7

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 8

what is the exeption of the urinary tract that is sterile?

Answer 8

urinary tract exept terminal urethra

Question 9

what will flush out many terminal urethral flora bacteria?

Answer 9

initial voiding

Question 10

what are different types of urine specimin for culture?

Answer 10

• initial urine
• collect after initial void, patient voids stops mid stream discards urine then collects next volume (MSSU)

Question 11

describe midstram specimin urine?

Answer 11

urethra flora will alwats grow in culture
no such thing as negative result
microbiology for culture under set conditions
bacteria multiply in log phase growth

quick way - dipslide method

Question 12

what is the chance of contamination with MSSU culture?

Answer 12

105 per ml - <1:100 chance of contamination if asymptomatic – ie 99 times out of 100, 105 bacteria per ml represents infection – if specimen = MSSU

Question 13

MSSU culture – 103  104

Answer 13

infection sometimes

if symptomatic probable that there is an infection

MSSU culture – 103  104 = 50 % chance of infection if no symptoms​

Question 14

MSSU culture – <103 =

Answer 14

ussually no infection

Question 15

when is mssu difficult to collect?

Answer 15

in yound children and the elderly

Question 16

what are problems with interpretation of urine cultures?

Answer 16

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

Question 17

what are the most common organisms that cause UTI’s?

Answer 17

Bacteria mostly = gut flora, especially E.coli​

Viral infection rare​

Question 18

what is the route of infection most commonly?

Answer 18

almost always ascending

Infection in kidneys: usually infection has spread up from bladder infection​

Upper urinary tract infection = more serious​

Question 19

what is infection of the urethra?

Answer 19

urethritis

Question 20

what is infection of the bladder?

Answer 20

cystisis

Question 21

what is infection of the kidney?

Answer 21

acute of chronic pylonephritis

Question 21

what is infection of the ureter?

Answer 21

ureteritis

Question 22

what are predisposing factors of a uti?

Answer 22

Stasis of urine ​

Pushing bacteria up urethra from below​

Generalised predisposition to infection

Question 23

what can cause stasis of urine?

Answer 23

Obstruction, whether congenital (presents in childhood) or acquired (adults). ​

Loss of ‘feeling’ (sensory loss) of full bladder - spinal cord/brain injury​

Question 24

what are causes of pushing bacteria up urethra from below?

Answer 24

Sexual activity in females​

Catheterisation (and other urological procedures)​

Question 25

what are generalised predisposition to infection?

Answer 25

diabetes

Question 26

at level of ureter what effect does obstruction have?

Answer 26

bilateral hydroureter
Bladder dilatation, bilateral hydroureter and bilateral hydronephrosis  chronic renal failure

Question 27

what does obstruction at level of renal pelvis on only one side cause?

Answer 27

unilatera; hydroureter

Unilateral hydroureter and unilateral hydronephrosis​

Question 28

what are the consequences of obstruction?

Answer 28

Proximal dilatation​

Slowed urine flow  Cannot flush out bacteria infection​

Slowed urine flow  sediments form  calculous (stone) formation  obstruction​

Some bacterial infections predispose to calculous formation​

Question 29

what is the approach to obstruction in children?

Answer 29

Numerous renal tract abnormalities​

Always investigate at 1st presentation and send to paediatric surgeons​

Most important example = vesicoureteric reflux​

Question 30

what is the vesicoureteric reflux?

Answer 30

Vesicoureteric reflux – decreased angulation

Question 31

what are comon causes of obstruction in males?

Answer 31

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

Question 32

what are comon causes of obstruction in women?

Answer 32

uterine prolapse​

Question 33

what effect does sexual activity have on lower urethral flora?

Answer 33

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

Question 34

what is the predisposition to bacteria travelleding up in women?

Answer 34

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 35

effect of catheterisation in utis?

Answer 35

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

Question 36

how can diabetes and chemotherapy lead to disposition to infection?

Answer 36

Glucose in urine​

Poor function of WBC​

Question 37

what are acute complications of utis?

Answer 37

severe sepsis and septic shock

Question 38

what are chronic complications of a uti?

Answer 38

Chronic damage to kidneys if repeated infections (chronic pyelonephritis)  hypertension, chronic renal failure​

Calculi  obstruction  Hydronephrosis  hypertension, chronic renal failure​