Urinary retention

This refers to a state in which urine is retained in the bladder. If you are unable to urinate no matter how hard you try, it is called complete urinary retention. It is seen in urethral stenosis, prostatic hyperplasia, spinal cord injury, urethral stones, etc. The patient will have a strong urge to urinate but be unable to do so, will complain of pain in the bladder, will break out in a cold sweat, and will have a tachycardia. If you touch the lower abdomen in such a case, you will find a hemispherical bladder swelling and strong tenderness. People with prostatic hyperplasia may suddenly become urinary retained while drinking alcohol. On the other hand, if you are able to urinate but are unable to expel all of the urine, and some of the urine remains in the bladder, it is called incomplete urinary retention. In many cases, it is accompanied by difficulty in urinating, and the amount of urine remaining in the bladder (residual urine) also increases. As the amount of residual urine increases, renal function is impaired, and there is a risk of eventually developing uremia. It is common in cases of prostatic hyperplasia, urethral stenosis, and spinal cord injury.

Catheterization is an emergency treatment for complete urinary retention. This is a method in which a thin tube (urethral catheter) is inserted through the urethra into the bladder to drain the urine that has accumulated in the bladder. If urinary retention does not improve with a single catheterization, a method called indwelling catheterization is used in which the catheter is left inserted in the bladder for a while. If catheterization is not possible due to urethral stricture, the bladder is directly punctured to drain urine.

[Masayoshi Tsuchida]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

膀胱(ぼうこう)内に尿が停滞する状態をいい、いかに努力しても排尿できない場合を完全尿閉という。尿道狭窄(きょうさく)、前立腺(せん)肥大症、脊髄(せきずい)損傷、尿道結石などにみられる。激しい尿意を催しながら排尿できず、膀胱痛のため七転八倒の苦しみを訴え、冷や汗を流して頻脈状態になる。こういう場合に下腹部を触ってみると、半球状の膀胱の膨隆を認め、強い圧痛がある。前立腺肥大症をもつ人は、飲酒中に突然尿閉になることがある。一方、排尿することはできるが全部排出できず、尿の一部が膀胱に残留する状態を不完全尿閉という。多くは排尿困難を伴い、膀胱内に残留する尿（残尿）も増加する。残尿が増えるにつれて腎(じん)機能が障害を受け、ついには尿毒症に至る危険がある。前立腺肥大症、尿道狭窄、脊髄損傷に多い。

　完全尿閉の救急処置として導尿法がある。これは、細い管（尿道カテーテル）を尿道から膀胱に挿入し、膀胱にたまった尿を排出させる方法である。尿閉が一度の導尿で改善しない場合は、留置カテーテル法といって、カテーテルをしばらく膀胱に挿入したままにしておく。尿道狭窄などで導尿が不可能なときは、膀胱を直接穿刺(せんし)して排尿する。

［土田正義］

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