A URINARY BLADDER with complete or partial loss of sensation. As there is no sensation of fullness, the individual is either unable to pass urine (retention of URINE), or the bladder empties automatically, usually every few hours. Affected individuals are at risk of urinary-tract infections and back pressure on the KIDNEYS, leading to renal failure. The condition may be caused by spinal injury, SPINA BIFIDA or any disorder which produces NEUROPATHY.