Urinary Tract Infection Flashcards
Definition of micturition
Urination
Presentation of UTI
Dysuria Frequency Smelly urine Cloudy urine Flank pain Urgency Chills Strangury Very young - unwell - failure to thrive Very old - incontinence - off their feet
Definition of dysuria
Pain (usually suprapubic) on micturition
How much of the CO does the renal blood flow get?
20 - 25%
What does urine output change with?
Oral intake of fluids
If increased fluid intake, how does that lead to increased urine output?
Resorption of fluid is diminished
Do ureters store urine?
NO - they have a continuous flow of it
What stops the reflux of urine up the ureter from the bladder?
Increasing pressure from the bladder as it fills, which closes off the ureter
What are the normal properties urine?
Low pH
High osmolarity
High ammonia (NH3)
What properties do prostatic secretions have?
Bacteriostatic
What parts of the urinary tract are sterile?
All of it except from the terminal urethra
Would a suprapubic aspirate of urine be non-sterile or sterile?
Sterile
What is a urinated specimen always contaminated with? What may get rid of this?
Terminal urethral flora
Initial voiding will flush out any terminal urethral floral bacteria
What does MSSU stand for?
Mid stream specimen of urine
How does a MSSU work?
Patient voids and then stops mid stream, discarding urine, then collects next volume of urine
In a MSSU, will there still be urethral flora present?
YES - it is diminished but always present
What level of bacteria on MSSU usually shows an infection?
10 ^ 5
If the MSSU shows bacteria of 10^3 to 10^4, what may this indicate?
Sometimes an infection is present
- probably if have symptoms
- 50% chance of infection if no symptoms
If the MSSU culture has bacteria <10^3, what does this indicate?
Usually NO symptoms
Who is a MSSU difficult to collect in?
Elderly
Young children
What is the most common organism to cause UTI?
Bacteria - E coli
How common is it to get a viral infection that causes a UTI?
Rare
What route of infection of a UTI is it almost always?
Ascending
Name of inflammation of urethra
Urethritis
Name of inflammation of the bladder
Cystitis
Name of inflammation of the ureter
Ureteritis
Name of inflammation of the kidneys
Acute pyelonephritis
What does acute pyelonephritis if recurrent/prolonged infection lead to?
Chronic pyelonephritis
Predisposing factors to UTI (Pathology)
Stasis of urine
Pushing bacteria up urethra from below
Generalised predisposition to infection
Causes of stasis of urine
Obstruction
Loss of feeling of full bladder (spinal cord/brain injury)
Causes of bacteria being pushed up from urethra from below
Sexual activity in females
Catheterisation and other urological procedures
What is an example of a generalised predisposition to infection?
DM
What would obstruction at the level of the urethra lead to?
Upper urethral and bladder dilation
What would upper urethral and bladder dilatation lead to?
Bilateral hydroureter
What can bilateral hydroureter lead to?
Bladder dilatation ->
Bilateral hydroureter ->
Bilateral hydronephrosis ->
Chronic renal failure
If there was obstruction in one ureter only, what would this lead to?
Unilateral hydroureter
What would unilateral hydroureter lead to?
Unilateral hydronephrosis
Consequences of obstruction
Proximal dilatation
Slowed urine -> cannot flush out bacteria -> infection
Slowed urine flow -> sediments form -> calculous (stone) formation -> obstruction
More and more of these
What is the triad of the consequences of obstruction?
Infection
Calculi
Obstruction
Pathology of vesicoureteric reflux
Decreased angulation of insertion of ureter at an angle into the bladder
Most common cause of obstruction in children
Vesicoureteric reflux
Causes of male adult obstruction
Benign prostatic hyperplasia of prostate
Tumours
Calculi
Causes of female adult obstruction
Uterine prolapse
Tumours
Calculi
Predisposing factors for UTI in females
Female - short urethra
Lack of prostatic bacteriostatic secretion
Sexual activity
Pregnancy
What reduces chance of UTI after sexual activity in females?
Voiding after intercourse
Why does pregnancy predispose you to UTIs?
Pressure on the ureters and the bladder
Complications of UTI
Severe sepsis and septic shock
Chronic damage to the kidneys if repeated infections (chronic pyelonephritis) leading to HTN and chronic renal failure
Calculi causing obstruction leading to hydronephrosis leading to HTN and CRF
Name if inflammation of the prostate
Prostatitis
Name if inflammation of the epididymis/testis
Epididymo-orchitis
Which gender gets UTIs more?
F > M 3:1
What % of women are affected by a UTI at somepoint in their lives?
30%
Why is UTI common in pregnancy?
Progesterones lead to relaxation of smooth muscle of the uretus - incidence of reflux is high
Why are urine infections very common in hospitals?
Catheters
Immunocompromised
Risk factors for UTI
Immunosuppression Steriods Malnutrition Diabetes CKD Female Age
Predisposing factors for UTI
Female - short urethra
Sexual intercourse and poor voiding habits
Congenital abnormalities e.g. duplex kidney
Stasis of urine due to poor bladder emptying
Foreign bodies e.g. catheters, stones
Oestrogen deficiency in post menopausal women
Fistula between bladder and bowel
Spermicide coated condoms and diaphragms
Why does a short urethra predispose you to UTIs?
Easier for microorganisms to transfer from the perineum/rectum
Why are oestrogen deficient post menopausal women at risk of UTIs?
Lack of oestrogen leads to a dry perineal area
What can help prevent UTIs in any age of women?
General toilet hygiene - wiping from front to back
Causative organisms of UTI
E coli Proteus mirabilis Klebsella Enterobacter Pseudonomonas aeruginosa Coagulase negative staphylococci Enterococci Group B strep Staph aureus
Which of gram -ve or gram +ve bacteria are more common to cause UTIs?
Gram positive
Where do the organisms usually originate from in UTI?
Bowel
How do the organisms spread to the Urinary tract system?
Transurethral route
- preurethral area contaminated (recurrent UTIs, diaphragms, bubble baths)
- urethra to bladder (intercourse, catheter)
- bladder and up ureters
Bloodstream
- certain parasites can attack the bladder via the blood e.g. schistosomiasis
Lymphatics
Can UTIs eventually cause AKIs?
Yes
Presentation of UTI in children
Diarrhoea Excessive crying Fever N + V Not eating
What is strangury?
The uncomfortable feeling of wanting to void but not being able to
Need to pee and a small amount comes out - then need to pee and nothing comes out - this is due to cystitis
Presentation of acute pyelonephritis
Pyrexia Poor localisation Loin tenderness at the renal angle Signs of dehydration Turbid urine
Investigations of UTI
MSSU Urinalysis - blood, leucocytes, protein, nitrites Microbiology in lab In children, men or frequent UTIs - USS - IVU
What does MSSU stand for?
Mid stream specimen of urine
What are the principles of management of a UTI?
- Identify the infecting organism and treat
2. Identify predisposing factor and treat if possible
Treatment of UTI
Oral fluids
Antibiotics
Why does oral fluids treat a UTI?
Flushes out the system
What antibiotics are used to treat UTI?
Amoxicillin
Cephalosporin
Trimethoprim
What abnormally urinary tract causes could cause UTI?
Anatomical/neurological abnormalities
Stones
DM
What can reflux nephropathy present with in children?
UTIs
How is reflux nephropathy assessed?
USS
Biochemistry
Treatment of reflux nephropathy
Surgery
Treatment of recurrent UTI infections
Fluid intake 2L/day Void every 2-3 hours by day Void before bedtime Void before and after intercourse Sometimes advised to not micturate in one go - stop and continue
Treatment of a catheter induced UTI
Antibiotics
Replace catheter
Presentation of chronic pyelonephrtiis
Scarring and clubbing
HTN
CRF
Reflux
What % of people with chronic pyelonephritis progress to renal failure?
15%
Complication of nitrofurantoin
Lung fibrosis
What causes sterile pyuria?
Antibiotics Renal TB Appendicitis Prostate Chlamydia Renal calculi PCKD Pregnancy Catheter
Investigation of choice for reflux nephropathy
Micturating cystography
