在噁心嘔吐、食慾不振的病人中，有一群因症狀不具特異性、不易診斷而可能造成延誤治療者，是上腸繫膜動脈症候群(superior mesenteric artery syndrome)病人。因十二指腸第三部分受到上腸繫膜動脈和腹主動脈壓迫造成十二指腸阻塞症狀。此症候群盛行率低，診斷不易，易發生在體重快速減輕的病人上。這篇個案報告將介紹這個少見的症候群的臨床症狀、診斷標準、治療與預後。當面對噁心嘔吐、食慾不振的病人時，上腸繫膜動脈症候群是個不可忽略的鑑別診斷。

Among the patients experiencing the symptoms of nausea and poor appetite, some will finally be diagnosed with superior mesenteric artery (SMA) syndrome, an unusual syndrome with various symptoms deriving from proximal intestinal obstruction caused by the compression of the third portion of duodenum due to the narrowing space between superior mesenteric artery and abdominal aorta. SMA syndrome has a low prevalence around 0.1-0.3%, occurring mostly in patients with significant weight loss and leading to mesenteric fat pad loss. In this case report, a 46-year-old woman with significant body weight loss was diagnosed with SMA syndrome. When examining patients reporting unintentional weight loss and symptoms of nausea and poor appetite, SMA syndrome should be taken into consideration as a rare but important differential diagnosis.