潰瘍性大腸炎診断基準の問題点―非連続性病変の面から

Is a Revision Necessary for the Japanese Diagnostic Criteria of Ulcerative Colitis?

要旨　自験潰瘍性大腸炎（UC）症例を対象とし，虫垂開口部とそのほかの非連続性病変を内視鏡所見と組織像から検討した．1）UC114例中，虫垂開口部病変を34.2％に，虫垂開口部以外の非連続性病変を14.9％に認めた．前者陽性例では陰性例よりも後者の陽性率が高かった（38.4％vs2.4％，p＜0.001）．3例は区域性大腸炎であった．2）遠位型活動期UC53例では，虫垂開口部病変の有無で臨床像，内視鏡的罹患範囲，臨床的活動性，治療の有無，使用薬剤に差はなかった．3）大腸各区域から生検を施行した40例では，虫垂開口部病変の有無にかかわらず虫垂開口部と上行結腸で内視鏡所見と組織所見が乖離し，上行結腸では両者に有意な関係を指摘できなかった．生検標本で直腸からの連続性病変が示唆されたのは13例（32.5％）で，20例（50％）では直腸と虫垂開口部を含む非連続性病変と考えられた．以上より，UCでは深部大腸の非連続性病変はまれではないと結論した．

　Continuous inflammation within the colorectum is one of the characteristic features of ulcerative colitis (UC). The aim of this investigation was to see whether discontinuous involvement is a characteristic not included in the Japanese criteria for diagnosing UC. Based on colonoscopic findings, we found skipped areas of involvement at the appendiceal orifice in 34% and other patchy areas of inflammation in 14.9% of patients with UC. In patients with active distal UC, neither clinical features, extent of the continuous involvement, disease activity nor therapies applied were different in patients with appendiceal involvement from those without it. There was a trend for endoscopic grade to be dissociated from histologic grade of inflammation in the cecum and in the ascending colon. Review of multiple biopsy specimens revealed that continuous involvement from the rectum to the proximal colon accounted for only 32.5% of patients, and in half of the patients the rectum and the appendiceal orifice were simultaneously affected by inflammation while other segments within the colorectum were spared. These findings suggest that skipped areas of inflammation are not rare events in patients with UC. Thus, the clinical diagnosis of UC should not be changed even when such skipped areas of involvement are found.