3)大腸の出血性疾患

Differential Diagnosis of Colonic Hemorrhagic Diseases

要旨　大腸出血性疾患を頻度順に述べると大腸癌・大腸ポリープ，炎症性腸疾患，虚血性大腸炎，大腸憩室，感染性腸炎であった．また，大腸出血性疾患の頻度を年齢別に検討したところ，炎症性腸疾患が若年群では最も高頻度で，大腸癌・大腸ポリープは中年群・高年群で最も高頻度にみられた．また，感染性腸炎は若年群や中年群で，大腸憩室は高齢群・中年群で，急性出血性直腸潰瘍症は高齢群で，虚血性腸炎はどの年代群でも比較的高率に認められた．大腸出血性疾患のうち急性発症で血性下痢を伴うものは，虚血性腸炎，感染性腸炎，抗生物質起因性腸炎などが考えられる．慢性的な血便は，大腸癌，潰瘍性大腸炎，アメーバ赤痢，腸結核，Crohn病，腸型Behҫet病，単純性潰瘍が考えられる．大量の血便排出は，憩室炎，vascular ectasia，急性出血性直腸潰瘍，潰瘍性大腸炎，Crohn病などが考えられる．脳血管障害などの重症基礎疾患を有し長期臥床中の高齢者が，無痛性で大量の新鮮血排出を来した場合，急性出血性直腸潰瘍であることが多い．

　The colonic hemorrhagic diseases, in order of frequency, include colon cancer/polyp, inflammatory bowel disease (IBD), ischemic colitis, colon diverticula and infectious colitis.

　The frequency of various colonic hemorrhagic diseases was evaluated according to the groups age of the cases. In the young age group (≦40 y.o.), IBD was the most frequent colon hemorrhagic disease. In middle age (41～64 y.o.) and among seniors (≧65 y.o.), colon cancer/polyp was the most frequent colon hemorrhagic disease.

　Among colonic hemorrhagic diseases, the disease with acute onset and bloody diarrhea is commonly thought to be ischemic colitis, infectious colitis or drug-induced colitis. The disease with chronic bloody stool is commonly thought to be colonic cancer, ulcerative colitis, amoebiac colitis, colonic tuberculosis, Crohn's disease, or Behҫet disease/simple ulcer. The disease with massive bloody stool is commonly thought to be colon diverticula, vascular ectasia, acute hemorrhagic rectal ulcer, ulcerative colitis or Crohn's disease. Especially, in cases where patients with severe and bedridden condition presented massive fresh bloody stool, acute hemorrhagic rectal ulcer is the diagnosis most usually made.