小腸アミロイドーシスの治療と経過

Clinical Course of Amyloidosis of the Small Intestine

要旨　十二指腸～空腸にアミロイド沈着が確認された11例を対象とし，治療経過と予後を検討した．麻痺性イレウスを呈した8例では，平均2.8か月間の完全静脈栄養（TPN）が臨床症状の改善のみならず，X線および内視鏡像の著明な改善をもたらした．すなわち，TPN治療後の小腸二重造影像では，治療前に認められた結節状陰影が完全に消失し，微細顆粒状隆起の多発から成る粘膜粗糙像に変化していた．TPN後の長期予後は良好であり，平均4.3年の間イレウス症状の再発はみられなかった．一方，中等度～高度の腹部症状を欠く慢性期の患者8例の小腸X線像は，平均2.7年の経過観察中ほとんど不変であった．以上の成績より，急性期に出現する結節状陰影は粘膜下層の虚血性変化を反映した所見であるのに対し，慢性期に描出される微細顆粒状隆起はアミロイド沈着を直接反映した所見であると推測された．したがって，後者は本症の早期診断上極めて重要な所見と考えられた．

　The purpose of the present investigation was to elucidate clinical course and prognosis of primary or secondary amyloidosis of the small intestine as well as to determine the most useful radiographic finding in diagnosing it at an early stage. Eleven patients with amyloidosis involving the duodenum and/or upper jejunum were evaluated. Of these, 8 patients had paralytic ileus and received total parenteral nutrition (TPN), which was effective in improving subjective symptoms and diminishing stool occult blood. Furthermore, double contrast study of the small intestine taken few months after the start of TPN revealed coarse mucosal appearance consisting of innumerable fine granular elevations replacing multiple nodular lesions which were commonly seen at acute stage.

　During the follow-up period ranging from 20 to 118 months (average 4.3 years) after TPN therapy, there was no recurrence of paralytic ileus or severe abdominal symptoms. Repeated small intestinal series, however, showed no definite changes in the lesions for a relatively long period of time (2.7 years on average) .

　Our results suggest that multiple nodular lesions frequently seen at acute stage may be caused by ischemic changes in the submucosal layer of the intestine, whereas innumerable fine granular elevations often seen at chronic stage may directly reflect amyloid deposition in the lamina propria. Therefore, the latter is considered to be the most important finding for early diagnosis of this disease.