Kidney and Urinary Tract Infections Flashcards
What is a urinary tract infection (UTI)?
- Refer to an infection of any part of urinary system from kidney to bladder
- Presence of characteristic symptoms + significant bacteruria
- Significant bacteruria = > 105 colony forming units/ml
- In absence of symptoms, this bacteruria is termed asymptomatic bacteruria
UTIs can be categorised depending on the location of the infection.
What is the difference between upper and lower UTI?
- Upper UTI → infection of kidney (pyelonephritis)
- Lower UTI → infection of baldder (cystitis)
What is the difference between uncomplicated and complicated UTI?
- Uncomplicated → if occuring in healthy non-pregnant adult women
- Complicated → Presence of factors that increase risk of treatment failure (eg. DM, structural, catheter, other devices and all UTIs in men); UTIs occuring in men are generally considered complicated as many occur in children and elderly in association with urological abrormalities, malignancy or immunosuppression
Which organisms are responsible for UTIs?
- E. Coli (most common: 75-90%)
- Proteus mirabilis
- Klebsiella pneumoniae
- Staphylococcus saprophyticus
What are ESBL infections?
- A growing number of UTIs are extended-spectrum beta-lactamase (ESBL) E. Coli
- Highly resistant to most beta-lactam abx
- Growing cause of hosp-acquired infections associated w/ poor outcomes
- Higher risk → prior administration of abx / length of ITU stay / urinary catheter presence
- Rx → broad-spectrum abx eg. carbapenems
Why are UTIs uncommon in men?
- Longer urethra
- Prostatic secretions have antimicrobial properties
- Periurethral drier than women’s
What are the risk factors for UTIs?
- Recent sexual intercourse
- Diabetes
- History of UTIs
- Spermicide use
- Catheters (major RF in secondary care)
What are clinical features of UTI?
- Dysuria / Frequency / Urgency
- Incontinence
- Suprapubic/flank pain
- Haematuria
- N+V / Fever / Rigors
- Confusion
- Costovertebral angle tenderness
What is urosepsis?
- UTI → Sepsis
- Suspect if SIRS going on (2 or more of below):
- Temp > 38C or < 36C
- HR > 90 bpm
- RR > 20
- WCC > 12 or < 4
What is the definitive diagnosis of UTI based on?
- Typical clinical features associated with positive lab evidence of pyuria +/- bacteriuria
- In young, non-pregnant females a clinical diagnosis suffices
- In complicating factors, further lab testing is necessary → urine dip, MC+S
What does urine dipstick show for UTI?
- Leucocytes
- Nitrites
Urinary MC+S can help guide antibiotic sensitivities
What other investigations can be done for UTI?
Used for those who don’t respond to treatment, present w/ severe infection or have atypical presentation or underlying comorbidities
- FBC / U+Es / CRP → raised inflammatory markers + impaired renal fxn (?AKI)
- USS or CT for complicated or uncomplicated UTI that doesn’t respond to treatment → abscess, haemorrhage, calculi, obstruction and emphysematous pyelonephritis
Management of UTIs involves the prescription of appropriate antibiotic therapy according to local guidelines and concordance with any culture results.
What is the management for uncomplicated UTI?
- Trimethoprim (CI: pregnancy) or Nitrofurantoin (CI renal impairment)
- Trimethoprim 200mg BD 3d (women) or 7-14d (men)
- Nitrofurantoin 50mg QDS or 100mg MR BD 3d (women) or 7-14d (men)
What is the treatment for acute uncomplicated pyelonephritis that doesn’t require admission to hosp?
- Oral fluroquinolone 500mg eg. Ciprofloxacin 12hrly for 14 days
What is the treatment for acute complicated cystitis?
Oral course fluoroquinolone
