急性症状を呈する胃アニサキス症―特に胃壁内穿入幼虫の内視鏡およびレントゲン所見とその臨床像

Gastric Anisakiasis Presenting Acute Gastrointestinal Symptoms: with special references to the endoscopic and roentgenographic findings of Anisakis larva penetrating into the wall of the human stomach and to its clinical features

　いきのよい生の魚をたべて“あたった”という話を聞くことがよくあるが，かかる場合，一般に急性胃（腸）炎，食あたり（食中毒）あるいは胃痙攣などとしてすまされることが多い．ところがこのような症例を早期に胃ファイバースコープで観察すると，ときに生きたアニサキス様幼虫が胃壁内に穿入しっっある現場を見出しうることを知り，以来われわれは食あたり様の急性症状を呈する症例と，アニサキス幼虫との関連性に着目し，胃内視鏡の立場から検討をっづけてきた．その後，この虫体はレントゲン写真でもよくうっし出せることが分った．

　これらについては，すでに機会あるごとに発表してきたが^1)2)3)4)，このような急性胃症状を呈する胃アニサキス症を，われわれは便宜上，“急性胃アニサキス症”と称してきた．これは再感染による劇症型ともいうべきものである．

　It was previously reported that timely fiberscopic observation occasionally revealed Anisakis-like larva penetrating into the gastric wall. The larva was also visualized radiographically in patients with “food poisoning” symptoms occurring several hours after eating raw foods that contained Anisakis-like larvae.

　Temporarily we call such a case as “acute gastric anisakiasis.” and its symptoms are usually more severe due to re-infection. So far we have experienced 46 such cases, identifying parasitologically all the parasite bodies as those of Anisakis larva type Ⅰ, after picking them out with biopsy forceps under direct vision. The gastric body accounted for 80 per cent of the sites of larval penetration. The larva was rather transparent and whitish, exhibiting an impressive, brisk winding movement when seen through the fiberscope. In double contrast radiograph it was seen as linear translucence of various shapes.

　Clinically, 4 to 6 hours after ingestion of foods containing Anisakis-like larvae, considerably severe epigastric pain would arise as well as nausea and vomiting. In some cases even left abdominal pain and diarrhoea was observed. However, at this stage no hematologic changes such as eosinophilia were found. There was no seasonal or regional difference in the incidence of anisakiasis, nor was there any noticiable relationship between its frequency and the acidity of the gastric juice.

　Of 46 cases of anisakiasis, we have encountered 5 cases of ulcer and a single case of early cancer (Ⅱc) as complicating organic diseases of the stomach.

　We would like to point out that anisakiasis of the stomach may at times account for those acute gastric diseases usually regarded as acute gastritis, food poisoning or “gastric cramp.”