It can be caused by a lesion at any point in the urinary tract. Causes include urolithiasis, posterior urethral valves and ureteral herniation.
Obstructive uropathy
Interstitial cystitis
Emphysematous cystitis
Pyonephrosis
Hemorrhagic cystitis
Pyelonephritis
Eosinophilic cystitis
Hydronephrosis