Urinary Tract Infections Flashcards Preview

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Flashcards in Urinary Tract Infections Deck (34):

What is the presentation of UTI?

Dysuria (pain on micturition)


Smelly urine

Very young - failure to thrive

Very old - incontinnce, off their feet



What percentage of cardiac output is renal blood flow?

20 - 25%


How does urine change with oral intake of fluids?

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


How do ureters function?

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


How do the ureters interact with the bladder wall?

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


What is the content of normal urine?

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


What is a useful property of prostatic secretions?

They are bacteriostatic


What portions of the normal renal tract are sterile?

All except the terminal urethra


Suprapubic aspirate of urine is sterile


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

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


•MSSU – how to tell contamination from real infection?

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


10is usually an infection - unless contamination (chances of which are less than 1 in 100)

Contamination more likely if they are asymptomatic


What values are associated with infection 'sometimes'?

10or 104

Probably an infection if there is symptoms


50% chance if there is no symptoms


When is there usually no infection?

When the culture shows less than 103


What is a problem associated with MSSU culture interpretation?

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


What are the micro-organisms that cause UTI?

•Bacteria mostly = gut flora, especially E.coli

•Viral infection rare


What is the route of infection in UTI?

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


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

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


What are the predisposing factors to UTI?

Stasis of urine

Pushing bacteria up the urethra from below

Generalised predisposition


What are the causes of stasis of urine?


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


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

Sexual activity

Catheterisation (and other urological procedures)


What is a generalised predisposition to infection?



Why does stasis of urine cause UTI?

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


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

Upper urethral and bladder dilation

Bilateral hydroureter

Bilateral hydronephrosis - chronic renal failure


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

Causes unilateral hydroureter and unilateral hydronephrosis


What are consequences of obstruction?

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


What is a common cause of obstruction in children?

Vesicoureteric reflux -  decreased angulation at angle into the bladder 


What are common causes of obstruction in adults?

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

Women - uterine prolapse

Both sexes - tumours and calculi


How does spinal cord/brain injury predispose to UTI?

•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


How does sexual activity in females predispose to UTI?

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


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

•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


What is the effect of catheterisation on the urethral flora?

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


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

Glucose in urine

Poor function of WBC


Summary of when people get UTI's


What is an acute complication of UTI?

Severe sepsis and septic shock


What are chronic complications of UTI?

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


•Calculi - obstruction- Hydronephrosis - hypertension, chronic renal failure