大腸憩室症の最近の動向

Modern Concept of Diverticular Disease of the Colon

　大腸憩室はVoigtel（1804）によって初めて記載されたが，1900年以前にはほとんど知られていない稀な疾患であった¹⁾．それが1920年頃から増加の傾向を示し，近年に至っては60歳以上の1/3には存在すると推定される程の高頻度な疾患となり，‘fiber deficiency disease'と考えられるようになってきた．周知のように，欧米にはS状結腸憩室が多く，わが国では右側結腸憩室が多い．Painterらの結論するように，この疾患が欧米型の低残渣食の摂取が習慣化してから約40年後に発症してくるものならば，近い将来にわが国においても高頻度の疾患となる可能性がある¹⁾．したがってこの時期に，治療的に問題の多い欧米型大腸憩室をよく理解しておくことは意義深いことであろう．本稿では，従来わが国でしばしば取り上げられてきた右側結腸憩室はさて置いて，主として問題の多い左側結腸憩室の最近の動向に焦点を絞って述べることにしたい．

　Pathogenesis of colonic diverticular disease was introduced following Painter's theory which claimed that it is a fiber deficiency disease. Segmentation of the colon together with muscle contraction produces high intraluminal pressure which facilitates mucosal herniation through the bowel wall at the weakest point where the vessels penetrates, the commonest site of diverticula being along the taenia. The high pressure was noticed after administration of prostigmine or morphin and after meal in patients with diverticular disease. These functional and physiological abnormality well corresponds to histological abnormalities found in resected specimens; that is muscle thickening of the affected segment particularly of the sigmoid colon, the commonest site of the disease.Low residue diet, functional and muscle abnormality are the promoting factors of producing intraluminal high pressure to develop mucosal herniation, diverticula. This pathogenesis is applied only for diverticular disease of the sigmoid which is commoner in the western countries whereas the cause of the right sided disease is unknown. However, it is hoped that physiological study of the right colon through colonoscope will solve the question in the near future.