Pyuria

Pyuria or leukocyturia refers to >5 WBCs per field of view at 400x. The urine may be grossly cloudy.

• Dipsticks
  • Can test for the presence of leukocyte esterase, an enzyme produced by WBCs
  • Can test for nitrite -> positive indicates bacteriuria
    • However, it can be false negative (bacteria which don’t produce nitrite)
• Bacterial urine culture should be performed to check for bacteriuria
  • If culture is negative, it should be repeated
• Meares and Stamey’s 4-glass urine collection
  • Used to determine the location of the bacterial infection within the urinary tract
  • Only performed in men
  • Four glasses are taken
    • 1st glass – the first 10 mL of urine
    • The patient then voids another approx. 100 mL of urine
    • 2nd glass – another 10 mL of urine
    • 3rd glass – the patient’s prostate is massaged, and the fluid ejected from the urethra is collected
    • 4th glass – another 10 mL of urine after the prostate massage
  • The first glass represents the urethral specimen
  • The second glass represents the bladder specimen
  • The third and fourth glasses represent the prostate specimen
  • Each glass is cultured for bacteria and examined for WBCs -> which glass has bacteria will give information on the location of the infection
• Causes of bacteriuria + pyuria
  • Urinary tract infection
• Causes of sterile pyuria (no bacteriuria)
  • Infection which is treated with Abs
  • Stone
  • Mycobacterial or chlamydial infection
  • Presence or recent use of catheter or endoscopic procedure
• Causes of sterile pyuria with haematuria
  • Bladder cancer
  • Glomerulonephritis
  • Pyelonephritis
  • Interstitial nephritis
• Causes of bacteriuria without pyuria
  • Bacterial colonization of urine sample