Crohn病に合併した続発性アミロイドーシス11例の臨床的検討

Clinical Study of Crohn's Disease with Secondary Amyloidosis

要旨　Crohn病（以下CD）に合併した続発性アミロイドーシス（以下AMY）11例（CD疑診1例を含む）について臨床的検討を行い以下の結論を得た．①AMYがCDに合併する頻度は1.8％であった．②CDでは尿蛋白出現前に消化管AMYが発症する．③消化管生検では十二指腸生検による検索がAMY陽性率100％で直腸生検より高率であった．したがってAMYの診断には腎生検や直腸生検よりも十二指腸生検を行うべきである．④AMY合併は大腸型で少ない．⑤CD長期経過例を対照群として比較し，AMY合併群は対照群の経過不良群と同様に初診時の炎症や活動指数が高いものに，また中部小腸に病変を有し縦走潰瘍スコアが高いものに多い．したがってCDの活動性がAMY合併の一因であることが示唆された．全経過中6例に腎障害が出現し，3例が死亡し予後不良であった．

　Eleven patients with secondary amyloidosis associated with Crohn's disease (CD) were evaluated clinically.

　1) Secondary amyloidosis was complicated in 1.8％ of CD. 2) Intestinal amyloidosis occurred before proteinuria in CD. 3) Amyloid deposition in endoscopic biopsy specimen of duodenum was observed in 100％ of the cases, the deposition rate in the duodenum was higher than that in the rectum. Therefore duodenal biopsy should be considered rather than rectal or renal biopsy in order to find amyloid deposition. 4) Colitis type CD was less likely complicated with secondary amyloidosis. 5) Inflammation and activity index of CD with secondary amyloidosis on the first visit were as high as those of the poor prognostic cases. The incidence of secondary amyloidosis was higher in the cases of CD with lesions in the middle of small intestine and longitudinal ulcers of high activity score. So, the activity of CD may be related to the secondary amyloidosis. Six out of eleven cases were complicated with renal dysfunction, and three cases were deceased. Prognosis seemed to be poor in CD with secondary amyloidosis.