UTI Flashcards
Difference between bacteriuria and pyuria?
Bacteriuria = presence of bacteria in urine and can be symptomatic or asymptomatic Pyuria = presence of leucocytes in urine and associated with infection.
How do we categorise UTI?
Upper and lower UTI
- upper = infection of kidney and ureters (pyelonephritis)
- lower = infection of the bladder (cystitis)
uncomplicated vs complicated
- uncomplicated = occuring in healthy, non-pregnant adult woman
- complicated = presence of factors that increase the risk of treatment failure (diabetes, structural abnormalities, immunocompromised, men etc.)
Annual incidence of UTI in women?
10-20%
What is the most common organism causing UTI?
What are some other organisms which can cause UTIs?
E coli >50% of UTIs (gram neg bacillus - stains pink)
- proteus 10-15% and associated with renal stones
- klebsiella - 10% associated with hospital or catheter infections
- enterococci
- staph saprophyticus - young women
Describe the pathophysiology of UTIs.
What are the microorganism and host factors for UTIs to develop?
Why are women more prone to UTIs?
Urinary tract is normally sterile
UTI can develop from ascending spread of microorganisms from the urethra into the bladder (lower) or kidneys (upper) or haematogenous spread via the blood.
Majority is ascending microorganisms
Microorganism & host factors
- Host factors such as intercurrent illness, immunosuppression (steroid use) or co-morbidities (diabetes) can increase the risk of developing a UTI
- E coli contain fimbriae which allows them to infect the urinary tract as they adhere to the urothelium and increase bacterial survival
- pregnancy can cause stasis of urine increasing risk
- ureteric stones causing obstruction
- catheterisation allowing colonisation
- bowel flora in females and short urethra in female compared to male
- males prostatic secretions also have anti-microbial properties so less likely in males
- Peri-urethral area in men is usually drier
Risk factors for UTIs
- extremely common among young, sexually active females
- recent sexual intercourse
- increased bacterial growth (DM, immunosuppression, obstruction, stones, catheter, pregnancy)
- History of UTIs
- spermacide use
- decreased urine flow (dehydration, obstruction)
What procedure in hospital carries a major risk for UTIs? How do we prevent this?
Catheterisation
- insertion carries organisms into bladder
- formation of biofilms can also cause incomplete voiding and increase the risk of UTI further
- prevention: keep catheter closed, remove as soon as you can, don’t treat asymptomatic bacteria and replace catheter.
Should we treat asymptomatic bacteriuria UTI in pregnancy?
Yes - 20-40% develop into acute symptomatic pyelonephritis.
What is pyelonephritis? Who does it affect? How does it occur? Risk factors? Symptoms? (triad and others) Treatment? complications?
Upper UTI of the kidneys / renal pelvis usually due to bacteria
- Affects women <35 commonly
- associated with sepsis, systemic upset and rigors
- often fluid depleted and need resuscitation
risk factors
- same as UTI
- E coli, proteus, enterobacter common as found in bowel flora
- rarely haematogenous
symptoms
- triad: fever, loin pain and pyuria
- nausea and vomiting, flank pain at costovertebral angle, chills.
treatment
- IV antibiotics - broad spectrum (co-amoxiclav)
- Drain obstructed kidney
- Catheter
- Analgesia - paracetamol
- Fluid replacement
complications
- renal abscesses and emphysematous pyelonephritis (rare but life threatening)
What do we do about asymptomatic bacteriuria?
Asymptomatic bacteruria is the presence of bacteria in urine without clinical symptoms
Treatment depends on circumstance - always treat pregnant as risk of pyelonephrirtis (20-40%)
Clinical features of UTI? (signs and symptoms)
symptoms
- dysuria
- frequency
- urgency
- incontinence
- suprapubic pain
- haematuria
- nausea and vomiting
signs
- fever
- rigors
- flank pain
- confusion
- costovertebral angle tenderness
- if vaginal discharge = consider PID
When should we be worried about systemic inflammatory response syndrome and urosepsis?
SIRS is diagnosed if 2 or more of the following criteria are met
- Temperature >38, <36
- Heart rate >90bpm
- Respiratory rate >20
- WCC >12,000 cell/min3, <4000 cell/min3
How is UTI diagnosed?
Definitive diagnosis of UTI is based on typical clinical features associated with positive laboratory evidence of pyuria
What investigations would you do for suspected uncomplicated UTI/
urine dipstick = minimum investigations
Investigations for complicated UTIs?
further testing is necessary
- urine dipstick, urine microscopy and culture and sensitivity (MC&S) is key.
