正常情况下,当膀胱内贮尿量达400—500毫升时,人即产生尿意,在条件允许的情况下将尿液排出体外。但是,老年人患有某些疾病,如前列腺肥大、盆腔肿瘤压迫、尿道炎症、尿道狭窄、尿道结石等。因机械性的压迫使尿道产生梗阻;脑、脊髓疾病或损伤造成中枢神经系统功能障碍;肛门、直肠、阑尾炎以及其他腹腔手术后腹部疼痛刺 Under normal circumstances, when the bladder when the amount of urine storage 400-500 ml, people will produce urinary intention, under conditions permitting urine excreted. However, the elderly suffer from certain diseases such as benign prostatic hyperplasia, pelvic tumor oppression, urethral inflammation, urethral stricture, urethral calculus and the like. Urethral obstruction due to mechanical stress; Central nervous system dysfunction caused by brain, spinal cord disease or injury; Abdominal pain thorn after anus, rectum, appendicitis and other abdominal surgery