Urinary Tract Infection (UTI) Flashcards Preview

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Flashcards in Urinary Tract Infection (UTI) Deck (41):

What is dysuria?

Pain on micturition


How does a UTI present?

Smelly urine

Very young: unwell, failure to thrive

Very old: incontinence, off their feet


Why do the ureters enter the bladder at an angle?

Enter bottom of bladder at angle so that increasing pressure from bladder as it fills -> closes off ureter and stops reflux of urine


What are the bacteriostatic properties of the normal urinary tract?

Free flow of urine through normal anatomy- assumes drinking enough fluids

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

Prostatic secretions are bacteriostatic

Anti-bacterial antibodies


How much of the urinary tract is normally sterile?

All urinary tract except for terminal urethra


How can you bypass the terminal urethra to take a clean sample of urine?

Suprapubic aspirate of urine
-Needle straight into bladder


Why do we take a midstream sample (or suprapubic aspirate) for urine MC&S?

Urinated sample will always be contaminated by terminal urethral flora

Initial void will wash terminal urethra -> sample taken after will be more sterile avoiding false positives


Explain how you carry out a mid stream sample

Patient voids and stops mid-stream, discarding urine, then collects next volume of urine = MSSU (midstream specimen of urine


Can you ever get rid of all terminal urethral flora by a MSSU?


Urethral flora will be diminished by always present

Will always grow in culture so never a negative result


What does MSSU stand for?

Mid Stream Specimen Urine


How do you tell contamination from real infection in MSSU?

Microbiology for culture under set conditions

Bacteria multiply in log phase growth

10^5 per ml


A MSSU culture result of 10^3 would indicate what?

10^3 and 10^4 need to be interperated clinically:

-If symptomatic probably infection

-If asymptomatic 50% infection


In which populations is an MSSU difficult to collect?

Young children and elderly


What are the problems with interpretation of urine culture?

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


What micro-organisms cause UTI?

Bacteria mostly = gut flora, especially E. coli

Viral infection rare


What is the route of infection in UTI?

Almost always ascending from terminal urethra

Infection in kidneys has usually spread up from bladder infection


Which is more serious:
Upper UTI or Lower UTI?

Upper UTI more serious


What is urethritis?

INFECTION of urethra

Usually itis = inflammation but here almost always infection


What is cystitis?

Inflammation/infection of bladder


What is ureteritis?

Infection of the ureter


What is acute pyelonephritis?

Kidney infection/ inflammation

If recurrent/ prolongued infection -> chronic pyelonephritis


What are the predisposing factors for a UTI?

1. Stasis of urine

2. Pushing bacteria up urethra from below

3. generalised predisposition to infection


How can stasis of urine come about?

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

2. Loss of "feeling" of full bladder - spinal cord/ brain injury


How can pushing bacteria up urethra from below come about?

Sexual activity in females

Catheterisation (and other urological procedures)


What may cause a generalised predisposition to infection?

e.g. Diabetes


How does obstruction of the urethra effect the urinary tract?

Upper urethral and bladder dilatation

If this continues -> bilateral hydroureter -> bilateral hydronephrosis -> chronic renal failure


What does unilateral hydroureter indicate as opposed to bilateral hydroureter?

Unilateral = obstruction above bladder

Bilateral = obstruction below bladder


What are the consequences of obstruction?

Proximal dilatation

Slowed urine flow -> cannot flush out bacteria -> infection

Slowed urine flow -> sediments form -> calculous formation -> obstruction -> repeat cycle


What is the obstruction triad?

Infection -> calculi -> obstruction -> infection etc


What is obstruction in children usually caused by?

There are numerous renal tract abnormalities
-Usually one of these

Always investigate at first presentation and send to paediatric surgeons


What is the most important renal tract abnormality for obstruction in children?

Vesicoureteric reflux


What is vesicoureteric reflux?

Normally ureters insert into bladder at angle

Decreased angulation in vesicoureteric reflux -> ureter isnt closed off by increasing bladder pressure -> reflux -> hydroureter -> hydronephritis


What are common causes of obstruction in adults?

Males - Benign Prostatic Hyperplasia (NOT a tumour) -> functional and anatomical obstruction

Females - Uterine prolapse

Both sexes - Tumours and calculi


What is the residual bladder volume?

Volume of fluid left in bladder after urination

You want this to be as small as possible to prevent static urine


How does spinal cord/ brain injury predispose to UTI?

Decreased sensation -> no sense of when to micturate and do not know how to empty bladder completely -> leave urine in bladder -> high residual volume -> stasis of urine


How does female sexual activity tend to lead to UTI?

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


Why are females more predisposed to UTI?

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


How does catheterisation predispose to UTI?

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


How does diabetes predispose to UTI?

Glucose in urine

Poor function of WBC


What are the acute complications of UTI?

Severe sepsis and septic shock


What are the chronic complications of UTI?

Chronic damage to kidneys if repeated infections (chronic pyelonephritis) -> hypertension, chronic renal failure

Calculi -> obstruction -> hydronephrosis -> hypertension, chronic renal failure