Presentation of Diseases of the Kidney and Urinary Tract Flashcards
What is dysuria?
Pain on micturition (peeing)
Describe the UTI Presentation
- Dysuria, frequency, smelly urine
- Very young - unwell, failure to thrive
- Very old - incontinence
How does urine output change in with oral intake of fluids?
Resorption of fluid is diminished if increase fluid intake -> increased urine output
(drink more –> pee more)
Do ureters store urine?
No, only transfer urine from kidneys to bladder
Where do the ureters end?
At the trigone of the bladder, at an angle; angle to prevent reflux of urine up the ureters
What are two mechanisms to prevent reflux of urine up the ureters?
- Enter bladder at an angle
* Increasing pressure from bladder as it fills with urine, closes off ureter and stops reflux
Describe the bacteriostatic properties (prevents proliferation) on the urinary tract?
- 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
Describe the bacteria present along the renal tract
Urinary tract is sterile up until the terminal urethra, which is NOT sterile due to bacteria from skin moving in
What would a suprapubic aspirate of the normal renal tract show?
Aspiration and the culture –> is sterile in normal conditions
What is a problem with using urinated specimen to culture for bacteria?
Will always be contaminated by terminal urethral flora
How can urinated specimens be used to culture bacteria without being contaminated?
Use initial voiding (first pee) to flush out terminal floral bacteria and stop mid stream
Then collect next volume of urine = MSSU (mid-stream specimen of urine)
Urethral flora diminished but always present and will always grow in culture
What is the the difficulty with interpreting results with an MSSU?
Need to be able to distinguish contamination of terminal urethral flora from a real infection
Describe the results of an MSSU
- Bacteria multiply in log phase growth
- 10^5 regarded as infection (even if asymptomatic)
- 10^3-4 infection sometime, esp. if has symptoms (50% chance if no symptoms)
- < 10^3 usually no infection
- Not an absolute guide, need an overall picture of patient and if they have symptoms
What groups of people are hard to collect an MSSU sample from?
Eldery (incontinent) and young (hard to stop mid-stream)
Name microorganisms that can cause UTI
- Bacteria mostly - esp. E. coli
* Viral infection rare
What is the most common route of infection?
Ascending:
Travels upwards from the terminal urethral flora
Very rare to be haematogenous spread
Name the different inflammatory responses that infection can cause
- Urethra - urethritis
- Bladder – cystitis
- Ureter – ureteritis
- Kidney – acute pyelonephritis
Not always indicative of infection
What can occur after a recurrent/prolonged infection in the kidney?
Chronic pyelonephritis
What are predisposing factors for UTIs?
- Stasis of urine
- Pushing bacteria up urethra from below
- Generalised predisposition to infection
Name two causes of stasis of urine?
- Obstruction - congenital or acquired
* Loss of sensation of full bladder - spinal cord/brain injury
Name two causes of pushing bacteria up urethra from below?
- Sexual activity in females
* Catheterisation (and there urological procedures)
Name a condition which can predispose a person to an infection
Diabetes - macrophages don’t work as well in hypoglycaemia and high Glc in urine provides better conditions for bacteria to proliferate
How does stasis of urine cause a UTI?
Bacteria that do get higher up urinary tract do not get flushed out
What are the features of an obstruction?
- Upper urethral and bladder dilation above obstruction
- Bilateral hydroureter (dilation of ureter)
- Bilateral hydronephrosis (water in kidney)
Most distal the obstruction, the worse effects will be -> bilateral effect
If at level of renal pelvis -> one side only
What is are the features of a distal obstruction?
Prolonged bladder dilatation, bilateral hydroureter and bilateral hydronephrosis –> chronic renal failure
What is are the features of an obstruction at the level of the renal pelvis?
Unilateral hydroureter and unilateral hydronephrisis –> renal failure
What are the consequences of obstruction?
- Proximal dilatation
- Slowed urine flow -> cannot flush out bacteria -> infection
- Slower urine flow -> sediment form -> calculous (stone) formation -> obstruction (more dilatation, more infections and calculous formed)
How do calculi form?
Bacterial infection predispose calculous formation
Infection -> calculi -> obstruction -> (loop back to infection)
How does an obstruction present as in children?
- Numerour renal tract abnormalities
- Always investigate at 1st presentation and send to paed surgeon
- Most important - vesicoureteric reflux
What is the vesicoureteric reflux?
Decreased anglulation of the ureter as it enters into bladder –> this causes reflux of urine into ureter with hydroureter
What are common causes of obstruction in adults?
- Men – Benign Prostatic Hyperplasia (not a tumour) of prostate – enlargement causing functional and anatomical obstruction
- Women – uterine prolapse
- Both sexes – tumours and calculi
How can a spinal cord/brain injury predispose a person to stasis of urine and then UTI?
Decreased sensation -> no sense of when to micturate and do not know to empty bladder completely -> leave urine in bladder (high residual volume) -> stasis of urine -> bacteria able to proliferate
How does sexual activity cause UTIs?
In females sexual activity tends to move lower urethral flora up the tract (back wall of urethra is just in front of vagina)
How are females predisposed to contracting UTIs?
- 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 causing stasis
How do catheters and other urological procedures cause UTIs?
Any instrumentation of urinary tract tends to move lower urethral flora up the tract
Try and remove bacteria at terminal urethra first
What conditions can predispose a person to infection?
Glucose in urine
Poor function of WBC
Are UTIs in children concerning?
Yes, can have high BP, bilateratel hydronephrosus, chronic renal failure if untreated
Are UTIs in girls with clear sexual history concerning?
Not was much - maybe take urine culture and if it continues do more tests
Could be abnormality with tract
Are UTIs in girls no sexual history within 6 months concerning?
Yes
What are the acute complications of a UTI?
Severe sepsis and septic shock
What are the chronic complications of a UTI?
- Chronic damage to kidneys if repeated infections (chronic pyelonephritis) -> hypertension, chronic renal failure
- Calculi -> obstruction -> Hydronephrosis -> hypertension, chronic renal failure
