非特異性直腸炎の自然史

Natural History of Idiopathic Proctitis

　非特異性直腸炎（idiopathic proctitis）が潰瘍性大腸炎の範疇に入る疾患か否かについては賛否両論があり，直腸炎から典型的な潰瘍性大腸炎に移行する例の存在を理由に，両者が同一範疇に含まれるという考え^1)～4)と，移行は認められず両者は全く異なる疾患であるという考え⁵⁾⁶⁾が対立している．わが国においてもこの問題には賛否両論があることに変わりはない．この機会に，われわれが外来において診断，治療した直腸炎患者の経過をもとに，現時点における直腸炎と潰瘍性大腸炎との関係について検討を加えてみたい．

　直腸炎の中には様々な原因によるものが含まれるが⁷⁾，潰瘍性大腸炎に含まれる直腸炎を潰瘍性大腸炎型直腸炎（uc型直腸炎），潰瘍性大腸炎と関係のない直腸炎を非潰瘍性大腸炎型直腸炎（non-uc型直腸炎）と呼ぶことにする．

　Forty-one idiopathic proctitis and twenty-one proctosigmoiditis of ulcerative colitis type were collected and reviewed from clinical notes and biopsy histology in order to know their natural history. Proximal extension from proctitis to proctosigmoiditis in seven cases, to left or total colitis in six cases, and from proctosigmoiditis to proctitis in 15 cases and to left or total colitis in three cases were observed. Oral extension rate in proctitis was 31.7% by histologic and/or colonoscopic observations and 14.6% by histologic observation only, whereas it was 14.3% in proctosigmoiditis by histologic and/or colonoscopic observations. It was suggested that histologic observation was more acurate to know the extent of the disease. From these observations it was concluded that idiopathic proctitis belonged to ulcerative colitis with only differing diseased segment.