Renal System >
Urinary Tract Infections (UTIs)

“An infection of the urethra (urethritis), bladder (cystitis), or kidneys (pyelonephritis)”

Classifications
  • Uncomplicated – normal underlying genitourinary anatomy and physiology
  • Complicated – underlying anatomical or physiological abnormality predisposes to UTI e.g. outflow obstruction, response to medications
  • Recurrent – repeat infection with a new organism
  • Relapsing – repeat infection with the same organism
Risk Factors
  • Modifiable
    • Urinary retention
    • Sexual Intercourse
  • Non-Modifiable
    • Age (>60)
    • Female – shorter urethra
    • Renal failure
    • Immunosupression
    • Diabetes
    • Pregnancy
    • Menopause
    • Structural or functional urinary tract abnormalities (e.g. renal calculi)
    • Instrumentation of the urinary tract (e.g. catheterisation or cystoscopy)
Aetiology
  • Microbial Infection from faecal matter – most commonly E. Coli, Proteus, or Klebsiella Latrogenic
Pathophysiology
  • Bacteria ascend urethra (urethritis) → may reach the bladder (cystitis) → may ascend ureters to kidneys (pyelonephritis)
Clinical Presentation
  • General Symptoms:
    • Dysuria
    • Increased urinary frequency or urgency
    • Cloudy/foul-smelling urine
    • Haematuria
  • Pyelonephritis Symptoms:
    • Fever and tiredness
    • Nausea and Vomiting
    • Systematically unwell (agitation/severe confusion in older people)
    • Loin & Back pain
    • Costovertebral Angle tenderness
Investigations
  • Bloods:
    • FBC, CRP and U&Es.
    • Blood cultures and venous blood gases to assess tissue perfusion and lactate for systemically unwell patients
  • Imaging:
    • Bladder scan
    • Renal Ultrasound – any obstruction for pyelonephritis?
  • Special:
    • Urine Dipstick:
      • Leucocyte esterase and nitrites ± blood (both negative = unlikely UTI, only leucocyte esterase positive = intermediate chance UTI, nitrites positive = highly likely UTI). MC&S (if symptoms persist, determine causal microorganism)
Management
  • Male
    • Symptomatic relief with paracetamol + treat lower UTI without associated indwelling catheter with 7 days trimethoprim 200mg BD
  • Female
    • Symptomatic relief with paracetamol or NSAIDs.
    • Urethritis – 3 days trimethoprim 200mg BD or 3 days nitrofurantoin 50mg QDS
    • Cystitis – consider prolonged antibiotic therapy (up to 10 days)
  • Pyelonephritis
    • Acute setting – analgesia, fluids, anti-emetics and empirical antibiotic therapy (7 days ciprofloxacin or co-amoxiclav for first-line therapy)
  • Prevention:
    • Drink water
    • Empty bladder soon after intercourse
    • Management of casual conditions
    • Wipe front to back
Complications
  • For recurrent/relapsing UTIs
    • Permanent kidney damage from acute/chronic pyelonephritis due to untreated UTI
    • Urethral stricture in males
    • Sepsis

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