内視鏡下胆汁直接採取により診断したランブル鞭毛虫症の1例

Demonstration of Giardia Lamblia by Duodenoscopic Biopsy and Aspiration of Bile, Report of a Case

　ランブル鞭毛虫症（giardiasis）は上部小腸および胆道に寄生する原虫Giardia lambliaに起因し，分布は全世界的で保養地における流行や旅行者の下痢の原因として注目されている^1)～5)．わが国では衛生環境の改善と共に最近では診断されることが少なくなり，胆囊炎症状を呈する症例の報告が散見される程度である^6)～8)．今回われわれは原因不明の腹痛と便通異常を示す症例において，内視鏡下直接胆汁採取により，初めて本症を診断し，十二指腸・空腸生検組織の光顕ならびに走査電顕的検索により興味ある所見を得たので報告する．

　In recent years Giardiasis lamblia has been less frequently diagnosed in Japan and sporadic case reports are mainly those with manifestations of cholecystitis. In a case presented here initial diagnosis was made by demonstration of trophozoites in aspirated bile via duodenoscopic papillary cannulation.

　A 25-year-old man with recurrent episodes of abdominal pain and diarrhea of several years' duration was referred to the Kinki University Hospital for further evaluation and definite therapy. Recent weight loss was noted. Physical examination was unremarkable except for epigastric tenderness. Laboratory examination revealed eosinophilia (9%) and decreased PFT value (59.7%). Stools were negative for ova. Immunoglobulins were normal. Ultrasonograms of the abdomen and x-ray studies of upper gastrointestinal tract, biliary tract and pancreatic duct were normal.

　Direct aspiration of the pancreatic juice was performed after stimulation through an indwelling cannula in the papilla of Vater. Clusters of Giardia lamblia trophozoites were incidentally discovered on Papanicolaou smears of the sample stained with bile. Duodenoscopy was repeated to confirm the diagnosis by separate collection of duodenal and jejunal fluid, pancreatic juice and bile and by duodenal and upper jejunal mucosal biopsy. Trophozoites were demonstrated in bile, duodenal and jejunal contents, and in biopsy specimens of duodenal and jejunal mucosa. Scanning electron microscopy of the jejunum revealed trophozoites adherent to the villi.

　After a course of metronidazole treatment the patient became asymtomatic and Giardia trophozoites disappeared from the bile and biopsy specimens obtained by duodenoscopy. In patients with undiagnosed chronic G. I. symptoms Giardiasis should be suspected as a possibility. Duodenoscopic aspiration and mucosal biopsy should be useful if repeated stool examinations are negative.