大腸アメーバ症の1例

Amoebic Colitis, Report of a Case

要旨　患者は75歳，男性．1983年8月上旬より粘血便が始まり8月5日入院．大腸透視にて横行結腸にⅡa＋Ⅱc様の不整形潰瘍，横行結腸から盲腸にかけて多数のたこいぼ状のびらんを認めた．大腸鏡検査にても同様に不整形の潰瘍と盛り上がりの強いびらんを認めた．潰瘍を生検し，潰瘍の壊死物質中に赤痢アメーバを認め，大腸赤痢アメーバ症と診断した．metrcnidazole 1,500mg投与にて症状は完全に消失し，大腸鏡にても治癒が確認された．本症例ではX線・内視鏡検査でアメーバ赤痢が疑われたが，通常の糞便検査にては虫体が確認されず，潰瘍部からの直接生検にて虫体が証明され，確診された．

　A 75year-old man was admitted to Sada Hospital on August 5,1983, with complaints of mucous bloody stool. He had been in South East Asia for several years about 40 years ago. Since then he had never been abroad and he didn't have any diarrhea episodes. Physical examination showed nothing remarkable.

　Laboratory studies included a hemoglobin of 16.1g/dl, a leukocytes count of 10,400/mm³with a normal differential count, an erythrocyte sedimentation rate of 10mm/hr, and a positive CRP. Chemisty screening was normal. Amoeba was not detectable in stool by mlcroscopic examlnatlon.

　Barium contra ststudy revealed multiple tiny erosions surrounded by slight elevation in the transverse colon to the cecum (Fig. 1) and irregular ulcers in the transverse colon (Fig. 2). Colonoscopy demonstrated irregular ulcers in the transverse colon (Fig. 3), multiple varioliform erosions (Fig. 4) and linear ulcers on the folds (Fig. 5) in the right side of the colon. The patient was diagnosed as having amoebic colitis because of histologic examination with necrotic debris containing Entamoeba histolytica trophozoites (Fig. 6).

　His treatment with metronidazol 1.5g per day for two weeks resulted in complete resolution of his symptoms. Radiologic examination and colonofiberscopy after treatment revealed the disappearance of ulcers.

Endoscopic biopsy was useful in this case because several fresh stool examinations had been negative. It was the radiologic and colonoscopic examinations that detected evidence of this disease.