Pathology of Urinary Tract Infection

Question 1

What is the common presentation of a UTI?

Answer 1

Dysuria
Frequency
Smelly urine

Question 2

Approximately what proportion of the cardiac output do the kidneys receive?

Answer 2

25%

Question 3

Do the ureters store urine?

Answer 3

No, they have a continuous trickle of urine

Question 4

How is influx of urine from the ureters into the bladder stopped?

Answer 4

The ureters enter the bladder at an angle. When the bladder fills and expands this angle is shut off by compression by the bladder wall and urine ceases to enter

Question 5

Describe the pH, osmolarity and ammonia content of normal urine

Answer 5

Low pH
High osmolarity
High ammonia content

Question 6

What parts, if any, of the urinary tract are sterile?

Answer 6

The entire tract bar the terminal urethra, which is contaminated with perineal and rectal flora

Question 7

How can a sample of urine be taken in a completely sterile manner?

Answer 7

Suprapubic aspirate

Question 8

Describe the challenges of obtaining a non-contaminated sample of urine

Answer 8

Because the terminal urethra is contaminated, any urine sample passed by the patient will contain bacteria. Because the healthy bladder is completely sterile, this makes determining whether the bacteria in the sample is from the bladder or from the terminal urethra

Question 9

What is an MSSU?

Answer 9

A mid-stream specimen of urine, designed to avoid the initial flush of bacteria into the same from the first void of urine, but it will always be present

Question 10

How is it determined whether the flora cultured from a urine sample indicated a UTI or normal terminal urethral flora?

Answer 10

They are calculated in log, and a culture of 10^5 usually indicates infection

Below 10^3 usually rules out infection

Question 11

What are some causes of UTI?

Answer 11

Mostly bacteria - gut flora, especially e.coli

Viral infection rare

Question 12

Describe the rout taken by UTIs

Answer 12

Almost always ascending up the tract, the higher the infection the more serious

Question 13

What is the name for inflammation of the urethra?

Answer 13

Urethritis

Question 14

What is the name for inflammation of the bladder?

Answer 14

Cystitis

Question 15

What is the name for inflammation of the kidney (acute)?

Answer 15

Acute pyelonephritis

Question 16

What is the name for inflammation of the kidney (chronic)?

Answer 16

Chronic pyelonephritis

Question 17

What is urethritis?

Answer 17

Inflammation of the urethra

Question 18

What is the name for inflammation of the ureter?

Answer 18

Ureteritis

Question 19

Give three predisposing factors for UTIs

Answer 19

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

Question 20

What may cause stasis of urine?

Answer 20

Obstruction

Loss of bladder sensation

Question 21

What may cause UTI as a result of pushing bacteria up the urethra from below?

Answer 21

Sexual activity in females

Catheterisation (and other urological procedures)

Question 22

Describe the effects of an obstruction at the level of the urethra

Answer 22

There begins a dilation of the upper urethra and bladder, which leads to bilateral hydroureter
this progresses to bilateral hydronephrosis and chronic renal failure

Question 23

What is the effect of an obstruction at the level of the renal pelvis one on side only?

Answer 23

Unilateral hydroureter develops and progresses to unilateral hydronephrosis

Question 24

What make up the triad of consequences of obstruction?

Answer 24

Infection
Calculi
Obstruction

Question 25

What is the most important cause of obstruction in children?

Answer 25

Vesicoureteric reflux

Question 26

What is vesoureteric reflux?

Answer 26

Where there is decreased angulation of the point of entry of the ureter into the bladder wall. This means that the compression of the filling bladder does not fully compress the ureter and urine is allowed to reflex up the ureter

Question 27

What is the most common cause of obstruction in male adults?

Answer 27

Benign Prostatic Hyperplasia - functional and anatomical obstruction - not a tumour

Question 28

What is the most common cause of obstruction applying only to women?

Answer 28

Uterine prolapse

Question 29

How does loss of sensation of the bladder cause stasis of urine?

Answer 29

Decreased sensation in the bladder due to spinal cord or brain injury mens that the ability to know when to empty the bladder is impaired and stasis of urine results

Question 30

What factors inherent in women predispose them to UTIs?

Answer 30

A short urethra Lack of prostatic bacteriostatic secretion Closeness of urethral orifice to rectum Sexual activity Pregnancy - pressure on ureters and bladder

Question 31

Give two factors relating to diabetes which predispose to UTI

Answer 31

Glucose in the urine | Poor function of WBC

Question 32

What are acute complications of UTIs?

Answer 32

Severe sepsis | Septic shock

Question 33

What are chronic complications of UTIs?

Answer 33

Chronic damage to the kidneys if repeated infections (chronic polynephritis) which leads to hypertension and chronic renal failure Calculi, leading to obstruction, hydronephrosis, hypertension and chronic renal failure