UTI Flashcards
what is the presentation of UTI?
- dysuria
- pain, stinging or burning when passing urine
- frequency
- urgency
- cloudy, smelly urine
- incontinence
- suprapubic pain or discomfort
- confusion in elderly
how does UTI present in very young?
unwell & failure to thrive
how does UTI present in elderly?
incontinence and off their feet
what are some normal bacteriostatic properties of the renal tract?
- free flow of urine
- low pH, high osmolality and high ammonia content of normal urine (low pH kills bacteria)
- prostatic secretions are bacteriostatic
- anti-bacterial antibodies
what part of the renal tract is sterile?
All of it apart from the terminal urethra
why is an MSSU done in order to reduce level of contamination?
initial urine is heavily contaminated, so it is voided and then stopped mid-stream. The next volume of urine is collected in the tube and will be less contaminated than the initial volume.
- urethral flora diminished but always present
what number of CFU indicates infection from an MSSU culture usually?
105
what does it mean if a person has 103-4 CFU on microscopy?
infection sometimes
-if symptoms, treat
what may be a problem of interpretation of MSSU culture?
some bacterial species are not normally present in terminal urethra/ rectal flora and may be pathogenic at low colony numbers
what are the main organisms that cause UTI?
- E.Coli
- klebsiella
- enterococcus
- pseudomonas
- staphylococcus saprophyticus
- candida albicans (fungal)
what is the main route of infection?
almost always ascending
what are the 3 main predisposing factors for UTI (aetiology)
- stasis of urine
- pushing bacteria up urethra from below
- generalised predisposition to infection
what are the main reasons for stasis of urine and what are they due to?
- obstruction
- congenital
- acquired
- loss of ‘feeling’ of full bladder
* spinal cord/brain injury
what happens to bacteria that make their way up to the bladder?
their flagella cause them to stick to the epithelium and stay there & colonise- do not get flushed out
what does obstruction at level of urethra cause?
bilateral hydroureter –> bilateral hydronephrosis –> chronic renal failure
what does obstruction just below level of renal pelvis on 1 side cause?
unilateral hydroureter & hydronephrosis
what are the main consequences of obstruction? (3)
- proximal dilatation
- slowed urine flow–> cannot flush out bacteria –> infection
- slowed urine flow–> sediments form–> stone formation –> further obstruction
what are the most common causes of obstruction in adults?
men- BPH
women - uterine prolapse
what are the main causes of pushing bacteria up urethra from below?
- sexual intercourse
- catheterisation
what are some factors that lead to predisposition of the female sex to UTI?
- short urethra
- lack of prostatic bacteriostatic secretion
- closeness of urethral orifice to rectum
- sexual activity
- pregancy (puts pressure on ureters and bladder)
what are some other factors which may predispose to UTI?
- congenital abnormalities ie duplex kidney
- oestrogen deficiency in post-menopausal women
- fistula between bladder & bowel
- spermicide coated condoms
what may cause generalised predisposition to infection? (4)
- diabetes
- immunosuppression
- steroids
- malnutrition
what are acute and chronic complications of UTI?
- acute - acute pyelonephritis, sepsis, septic shock
- chronic
- chronic pyelonephritis–> HT –> renal failure
- calculi –> obstruction –> hydronephrosis –> HT, chronic renal failure
what is the difference between complicated and uncomplicated UTI?
- uncomplicated - healthy, sexually active young women, in which there is a clear correlation between episodes of UTI with having sexual intercourse
- complicated- those which occur in all other situations ie children, men, patients with abnormal renal tract etc. Require investigation
how do you investigate UTI?
MSSU
- Urine dipstick
- blood
- protein
- leucocytes
- nitrites: better indication of infection than leucocytes
- send for MC&S if either nitrites / leucocytes
what are leucocytes?
marker of inflammatory response
- leucocyte esterase tested for which is a breakdown product of leukocytes tht gives indication of no of leukocytes in urine
how do you treat uncomplicated UTI?
Trimpethoprim or Nitrofurantoin for
- 3 days for simple lower UTI
- 5-10days if immunosuppressed, abnormal anatomy or impaired kidney function
- 7 days for men, pregnant women or catheter related UTIs
if both trimethoprim/nitrofurantoin are contraindicated, what is given in its place?
Amoxicillin or Cefalexin
how do you treat complicated UTI?
ciprofloxacin or co-trimoxazole
what do UTIs in pregnancy increase risk of?
- pyelonephritis
- premature rupture of membranes
- pre-term labour
Mx in pregnancy?
1st line: Nitrofurantoin
2nd line: cefalexin or amoxicillin
for 7 days (even with asymptomatic bacteruria)
when is Nitro avoided in pregnancy?
3rd trimester as it is linked with haemolytic anaemia of newborn
when is Trimethoprim avoided in pregnancy?
in 1st trimester or if on any other medication that affects folic acid
