Pathology of UTI Flashcards
Give the 3 main clinical features of a presentation of UTI
- Dysuria (pain on micturition)
- Increased frequency of micturition
- Smelly urine
Give 2 extra features if the patient presenting is very young
Unwell
Failure to thrive
Give 2 extra features if the patient presenting is very old
Incontinence
Off their feet
What occurs in a normal renal tract when oral intake of fluids increases?
Increased urine output due to diminished resorption of fluid
Do ureters store urine?
NO; they have a continuous trickle of urine
How does the bladder prevent reflux of urine?
Ureters enter bladder at an angle
Increasing pressure from bladder, as it fills, closes off ureter and stops reflux of urine
Describe the pH, osmolality and ammonia content of normal urine?
LOW pH
HIGH osmolality
HIGH ammonia (NH3)
What is the nature of prostatic secretions?
They are bacteriostatic
As well as free flow or urine (in well hydrated people), low pH, high osmolality, high ammonia and bacteriostatic prostatic secretions, what is the last bacteriostatic property of the normal urinary tract?
Contains anti-bacterial antibodies
How much of the urinary tract is sterile?
ALL; except terminal urethra which is subject to skin (perineal) and gut (rectal) flora
Why should urine specimen for culture be collected after initial void?
Initial void of urine will be heavily contaminated by terminal urethral floral bacteria
What is a MSSU?
Mid-Stream Specimen of Urine
= patient voids and stops mid-stream, discarding urine, then collects next volume of urine (will ensure urine is mostly sterile)
Is there such a thing as a negative result for an MSSU?
NO; urethral flora will always grow in culture as will be diminished but still present
In the dip slide method, what is the normal MSSU culture bacteria per ml value indicating infection?
10^5 per ml
1:100 chance of contamination if patient is asymptomatic
What is the MSSU culture bacteria per ml value indicating PROBABLE infection if the patient also has symptoms?
10^3 - 10^4 per ml
In a culture value of 10^3-10^4 per ml, when a patient has NO symptoms, what is the chance there is an infection?
50%
What is the culture value of bacteria per ml indicating no infection?
<10^3
Which demographic is an MSSU generally difficult to collect in?
Young children and elderly