便秘の臨床的諸問題

Clinical Problems of Constipation

はじめに

　便通異常の実態を外来患者について調査してみると，表1¹⁾のとおりである．すなわち，都立豊島病院内科外来患者5,490名のうち，便通異常を訴えたものは377例（6.7％）で，このうち下痢が277例（4.1％），便秘が130例（2.3％），下痢・便秘交代が20例（0.3％）となっている．なお便秘患者は下痢患者より少ないが，便秘の場合には下痢と異なって，自宅療法を行ない，来院しない患者が相当にいると考えられる．

　便秘は腸疾患にもとづくことが多いが，必ずしも器質的病変によるとはかぎらず，機能的異常によることがむしろ多い．また全身性疾患の一つの症状として現われることもあるから注意しなければならない．

　便秘について，まず問題となるのは，その定義である．これについては諸家の意見を徴して検討を加えた．筆者らは，とくに治療を必要とするものを便秘症とよぶことにしている．なお便秘の発生機転，分類を文献的に検討し，各種便秘の特徴，症状を述べ，さらに診断については症例をあげて解説する．

1) Definition of constipation

　When there is either no defecation for more than three or four days or the stool is of insufficient amount even if defecation occurs daily, it is then called constipation. When associated further with pain and requiring medical management, the above mentioned symptoms can be regarded as constipation.

2) Originating mechanism

　Three phases are observed in defecation. Firstly, the stool enters the rectum from the sigmoid initiated by gastro-colonic reflex and its stimulus is conveyed to the spinal center, producing an urge to defecate. In the second place, through the urge the abdominal pressure is heightened and the contents of the colon are pushed downward, and by the contraction of the rectum they are propelled further. Thirdly, the stool is evacuated through the relaxation of the external sphincter. Any disturbance in this defecative mechanism causes constipation.

3) Causes of constipation

　Broadly they can be classified into passage disturbances of the bowel contents, abnormal morphology and disturbed function of the large intestine and clifficulty in defecation.

4) Classification

　The authors have divided constipation as follows: -

　1. Functional constipation

　　a) transient simple constipation

　　b) habitual constipation

　　　(1) atonic constipation

　　　(2) spastic constipation

　　　(3) rectum type functional constipation

　2. Organic constipation

　　a) constipation due to passage hindrance of the bowel

　　b) constipation through abnormal morphology of the colon.

5) Symptoms

　Transient constipation, also called environmental constipation, occurs following change in diet or mode of living. Most of spastic constipation belong to constipation type in the irritable colon syndrome and, as is different from atonic type, is often accompanied with abdominal pain. Many patients with spastic constipation tend to be nervous and complain of symptoms belonging to autonomic ataxia.

6) Differential diagnosis

　History taking, associated symptoms, examination of the stool, x-ray and endoscopic studies of the colon are very important factors in the discrimination between functional and organic constipations. Sometimes further diagnostic adjuncts may become necessary, such as character study, examination of the autonomic nervous system, and study in blood electrolytes, especially in kalium level.