潰瘍性大腸炎の初期病変―直腸病変の口側進展

Clinical Features and Proximal Extensionof Ulcerative Proctitis

要旨　潰瘍性大腸炎（UC）患者のうち発症時に直腸炎型であった症例は22.6％であり，さらにその中で41.9％は口側進展した．直腸炎型のおよそ半数は左側結腸炎型あるいは全大腸炎型の初期病変であり，経過中に口側進展を来す可能性がある．口側進展に関与する因子を明らかにする目的で，① 男女別，② 発症年齢別，③ 初発時重症度別，④ skip病変の有無，について検討したが，いずれも有意な危険因子ではなかった．口側進展を認めず直腸炎のみで手術に至る例はなく口側進展が手術の危険因子であると考えられた．初発時直腸炎型の累積手術率は5年で12.2％，10年で23.3％であり，さらに口側進展し手術に至った症例の80％が口側進展を認めてから2年以内に手術に至っていた．直腸炎型でcolitic cancerを発症した症例はなかった．活動性粘膜の範囲を正確に診断し，口側進展をくいとめることが手術率・腸管外合併症やcolitic cancerの合併を軽減する可能性が示唆された．

　To elucidate the incidence and risk factors for proximal extension of ulcerative colitis（UC）in the Japanese population, we investigated the backgrounds and clinical courses of UC patients according to our clinical records. 23％ of the UC patients had been initially diagnosed as having proctitis type, while 41.9％ of them exhibited proximal extension. The gender, age or severity at the time of initial diagnosis and the presence of skip lesions were not found to be associated with the incidence of the proximal extension in UC. Whereas the cumulative rate of surgery was 12.2％ at 5 years and 23.3％ at 10 years, no surgery was required for the patients without proximal extension. 80％ of the patients who exhibited proximal extension needed an operation within 2 years. No colitic cancer was detected in the patients with proctitis. Proximal extensions were thus regarded as being important risk factors leading to surgical operations in patients with ulcerative proctitis. Further analysis is therefore needed to identify the risk factors for the proximal extension of certain types of proctitis.