Urinary Tract Infection

Infectious Diseases

Symptomatic infection of the urinary tract; classified as lower (cystitis) or upper (pyelonephritis).

Causes

  • E. coli (~80%)
  • Klebsiella, Proteus
  • Staph saprophyticus (young women)

Risk factors

  • Female, sexual activity, pregnancy
  • Catheter, obstruction
  • DM, immunosuppression

Clinical features

  • Dysuria, frequency, urgency
  • Suprapubic pain
  • Pyelonephritis: fever, flank pain, vomiting

Investigations

  • Urine dipstick (nitrites, leuc esterase)
  • MSU MC&S before antibiotics
  • Bloods if systemically unwell
  • Imaging if obstruction suspected

Management

  • Lower UTI: nitrofurantoin 100 mg BD × 3 d (women) / 7 d (men)
  • Alternative: trimethoprim 200 mg BD (resistance-dependent)
  • Pyelonephritis: co-amoxiclav 7–14 d or ciprofloxacin 7 d
  • Pregnancy: nitrofurantoin (not 3rd trim), cefalexin

Complications

  • Pyelonephritis
  • Urosepsis
  • Renal scarring (children)

Clinical pearls

  • Treat asymptomatic bacteriuria only in pregnancy / pre-urological surgery
  • Send catheter sample, not bag urine

Educational — verify locally.

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