Causes of sterile pyuria
WBC’s in urine microscopy
Sterile pyuria refers to the presence of more than 5 white blood cells per high power field ( WBC’s / HPF ) in the absence of bacteria in a routine urine specimen.
Causes of sterile pyuria
Sterile pyuria can arise due to various causes. The following conditions must be considered as differential diagnosis for a case of sterile pyuria.
- Infectious etiology
- Urinary tract infection after treatment
- Bacteria like like Chlamydia trachomatis, Ureaplasma urealyticum and Mycobacterium tuberculosis
- Viral or fungal UTI
- Prostatitis
- Appendicitis
- Systemic conditions
- Acute febrile illness
- Congenital cyanotic heart disease
- Malignant hypertension
- Pregnancy
- Kawasaki disease
- Sarcoidosis
- Structural defects and impairment of renal physiology
- Hydronephrosis
- Nephrocalcinosis / Urolithiasis
- Vesicoureteral reflux
- Retained foreign body in urinary tract
- Polycystic kidney disease (PKD)
- Intrinsic pathology of kidney
- Papillary necrosis secondary to chronic analgesic nephropathy / obstructive uropathy / sickle cell nephropathy / diabetic nephropathy
- Tubulointerstitial diseases like interstitial nephritis, lupus nephritis and renal transplant rejection
Ref: Sterile pyuria: A differential diagnosis, Robert S. Dieter, Comprehensive Therapy, Fall 2000, Volume 26, Issue 3, pp 150-152
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