Urinary retention, or abnormal holding of urine in the bladder, is a common urological problem. Possible causes of acute urinary retention (sudden inability to urinate) include a blockage in the urinary system, stress or nerve problems. Chronic urinary retention (some urine is always left in the bladder after emptying) may be caused by bladder muscle failure, nerve damage, or obstructions in the urinary tract. Treatment for urinary retention depends on the cause.