Pathology of UTIs Flashcards
What are the 3 most common presenting symptoms of a UTI?
Pain (dysuria)
Increased frequency (polyuria)
Smell of urine
How much of the CO do the kidneys receive?§
20-25%
Do the ureters store urine?
NO
When there is an increase pressure in the bladder what happens to the vesicoureteric openings? Why?
Close
To prevent reflux of urine
What is the composition of normal urine?
Low pH
High osmolarity
High ammonia
Is normal urine sterile or non-sterile?
Sterile (bacterostatic)
All of the urinary tract is sterile apart from which area?
Urethra
What type of bacterial flora are present at the urethra?
Skin (perineal)
Gut (rectal)
When collecting a urine specimen, what type do you want? Why?
Mid-stream specimen of urine (MSSU)
Initial voiding with flush out terminal urethral bacteria
In a MSSU will bacteria be present?
Yes, urethral flora will be detected but to lesser extent
What do you use MSSU for?
Microbiology culture
In a MSSU culture if there is 10^5 bacteria /ml what would this suggest?
Infection (even if asymptomatic)
In a MSSU culture if there is 10^3/4 bacteria /ml what would this suggest?
Infection sometimes (if there are symptoms - treat)
In a MSSU culture if there is < 10^3 bacteria /ml what would this suggest?
No infection
In what cases can it be difficult to collect MSSU?
Young & elderly
What micr-organisms are responsible for caring UTIs?
E.coli (gut)
Which direction do bacteria move through urinary tract?
Ascend
Inflammation of the urethra is called?
Urethritis
Inflammation of the bladder is called?
Cystitis
Inflammation of the ureters?
Ureteritis
Inflammation of the kidneys is called?
Acute pyelonephritis
In recurrent/ prolonged infection, what can occur at kidney?
Chronic pyelonephritis
What are the 3 general predisposing factors to UTI?
Stasis of urine
Pushing bacteria back up urethra
General predisposition ot infection
What are some of the causes of stasis of urine?
Obstruction (acquired or congenital)
Loss of feeling of bladder - spinal cord injury
What are some of the causes of pushing bacteria back up urethra?
Sexual activity in females
Catheterisation
What are some cause which predispose people to infection?
Diabetes
Chemotherapy
Immunosuppression
If the urethra becomes obstructed, what occurs initially in the urinary tract?
Upper urethral & bladder dilation
If the urethra becomes obstructed, what can it lead to in the upper urinary tract?
Bilateral hydronephrosis
If one of the ureters becomes blocked, what will be observed?
Unilateral hydroureter leading unilateral hydronephrosis
What are the triad of consequences which occur in obstruction?
Dilation
Bacteria accumulation
Calculous formation
What renal tract abnormality is often seen in children leading to obstruction?
Vesicoureteric reflux
Why does vesicoureteic reflex occur?
Reduced angulation of ureters results in retrograde flux of urine from bladder
What can vesicoureteric reflux result in?
Hydroureter
What is a common cause of urethral obstruction in males?
Benign prostatic hypertrophy
What is a common cause of urethral obstruction in females?
Uterine prolapse
What is a common cause of urethral obstruction in both sexes?
Calculi & tumours
In those with spinal cord injuries, why can stasis of urine occur?
No sensation of micturition therefore bladder doesn’t fully empty (high residual volume)
What age range are UTIs most common in females?
Sexually active (20s)
What can predispose a woman to UTIs?
Short urethra Close relation of urethral orifice to rectum Sexual activity Pregnancy Lack of prostatic secretions
What are the properties of prostatic secretions?
Bacteriostatic
Why is it important to clean urethral orifice before inserting catheter?
Can push terminal urethral flora back up urinary tract
Why are those with diabetes predisposed to UTIs?
Glucose in urine
Poor function of WBC
What is an acute complication of a UTI?
Sepsis & septic shock
What is a chronic complication of UTI?
Chronic damage to kidneys (chronic pyelonephritis) > hypertension & chronic renal failure
