炎症性腸疾患と鑑別を要する感染性腸炎

Infectious Enteritides to be Differentiated from Inflammatory Bowel Disease（IBD）

要旨　炎症性腸疾患（IBD）と鑑別を要する感染性腸炎は，直腸からびまん性病変を認め潰瘍性大腸炎（UC）と鑑別を要する疾患と，回盲部病変を認めCrohn病（CD），Behçet病と鑑別を要する疾患に大別される．前者はアメーバ性大腸炎や細菌性腸炎，後者は腸結核，エルシニア腸炎などである．鑑別診断に最も有用なのは，疾患に特徴的な内視鏡所見である．生検組織所見では，感染症でも陰窩膿瘍や肉芽腫を認める場合があるが，適確な組織採取や培養検査，特殊染色，便汁培養などの検査を組み合わせることにより診断精度の向上に繋がる．また，画像所見に合わない薬物治療抵抗性の臨床経過をみた場合，感染の可能性を念頭に置き注意深く病歴の再聴取を行うことも，確診に繋がり重要である．

　Infectious enteritides that need to be differentiated from inflammatory bowel disease（IBD）are divided into two types : Enteric infections that may affect the distal colon and rectum（amebic colitis, bacterial enteritis,）requiring differential diagnosis from ulcerative colitis（UC）. And enteric infections that may affect the ileo-cecal segments（intestinal tuberculosis and Yersinia enterocolitis）necessitating differentiation from Crohn's disease（CD）. The essential points for differential diagnosis between IBD and enteric infections are disease-characteristic endoscopic findings. Histological examination of infectious enteritis often demonstrates granulomas or neutrophilic microabscesses in the crypts, but combinations of several examinations such as histological examination of biopsy from an appropriate site, culture of the biopsy specimen and culture of stool liquid gathered during endoscopies, may elevate precision of the diagnosis. When we examine patients with clinically intractable colitis, it is important to re-evaluate the clinical course in order to distinguish infectious enteritis from IBD.