Occlusion of catheter lumen by tight clothing
Catheter straps occluding the non-return valve of the
drainage bag
Incorrect positioning of the drainage bag above the level
of the bladder
Overfull drainage bag
Constipation
Occlusion of catheter eyelets by the bladder mucosa
Encrustation
Occlusion caused by blood clots, sediment or mucous
Bladder spasm caused by oversized urethral catheter,
incorrectly filled or oversized balloon or by detrusor
instability.