直腸肛門部の炎症性疾患―感染性腸炎の直腸肛門部病変

Anorectal Region of Infectious Colitis

要旨　感染性腸炎には直腸を好発部位とする疾患がみられ，性行為感染症（STD）の側面が強い疾患も多い．アメーバ性大腸炎は約9割に直腸病変を認め，出血あるいは周囲に紅暈を有するびらん・小潰瘍が内視鏡的特徴である．クラミジア直腸炎は下部直腸に限局したリンパ濾胞増殖症の像を示し，潰瘍性大腸炎や原因不明のリンパ濾胞増殖症との鑑別が必要である．サイトメガロウイルス腸炎も約半数に直腸病変があり，HIVの合併が多い．急性出血性直腸潰瘍，潰瘍性大腸炎，アメーバ性大腸炎などとの鑑別が必要である．細菌性腸炎の中で直腸に病変を来すカンピロバクター腸炎，腸管出血性大腸菌腸炎についても述べた．尖圭コンジローマは肛門周囲皮膚や肛門管に発生するが，直腸病変を来すこともあり，覚えておくべき疾患である．アメーバ性大腸炎，クラミジア直腸炎，尖圭コンジローマの多くはSTDである．これらの疾患の診断，鑑別診断について主に考察した．

　Several infectious forms of colitis, including STD（sexually transmitted disease）most commonly occurs in the rectum. 88％ of amebic colitis occurs in the rectum. Endoscopic features of amebic colitis are multiple erosions or small ulcers with redness and bleeding. Chlamydia trachomatis proctitis appears as lymphoid hyperplasia in the lower part of the rectum. Ulcerative colitis and idiopathic lymphoid hyperplasia are important in the differential diagnosis of chlamydia trachomatis proctitis. About 50％ of CMV（cytomegarovirus）enterocolitis occurs in the rectum. It often develops in patients with acquired immunodeficiency syndrome. Acute hemorrhagic rectal ulcer, ulcerative colitis and amebic colitis are important in the differential diagnosis of CMV enterocolitis. Most Campylobacter enterocolitis and some of Enterohemorrhagic Escherichia coli-induced colitis extend to the rectum. Condyloma acuminatum occurs in the anal canal and skin surrounding the anus, and sometimes extends to the rectum. Most cases of amebic colitis, chlamydia trachomatis proctitis and condyloma acuminatum are STD. We described diagnosis and differential diagnostic methods for these disease.