余田 篤, 青松 友槻

Atsushi YODEN, Tomoki AOMATSU

大阪医科大学小児科

Department of Pediatrics, Osaka medical college

キーワード : children, acute abdomen, intussusception, acute appendicitis, ultrasonography

小児の腹痛における画像診断として第1選択肢は単純Ｘ線写真であったが，超音波検査の方が情報量も診断率も高い．小児の急性腹症の中で頻度の多い疾患として，腸重積，急性虫垂炎などがあり，頻度の少ない疾患として，胆道拡張症，中腸軸捻転などがある．また，Henoch-Schönlein紫斑病と出血性腸炎は急性腹症として受診することもある．乳幼児では正確な問診や身体所見を得られないこともあり，腹痛を主訴に受診する乳幼児の診断に際して，超音波検査 は有用である．小児の急性腹症の中で超音波検査の感度と特異度の高い疾患は腸重積，急性虫垂炎，中腸軸捻転，胆道拡張症などで，超音波検査だけでこれらの四疾患の確定診断や除外診断が可能である．Henoch-Schönlein紫斑病と出血性腸炎では，急性腹症として誤って開腹術になることがあるが，これらの二疾患の超音波検査の特徴は小腸や大腸の腸管壁の肥厚である．超音波検査で肥厚した腸管壁が観察され，同時に虫垂炎と腸重積を否定すると開腹術を回避でき，これらの二疾患が鑑別に挙げられる．小児の急性腹症の代表的な疾患で，超音波検査が確定診断に最適である腸重積，急性虫垂炎，中腸軸捻転，胆道拡張症と，確定診断は困難であるが超音波検査が有用なHenoch-Schönlein紫斑病と出血性腸炎について疾患の特徴，超音波検査の描出法そして診断について解説する．

A child with an acute abdomen requires history-taking and a physical examination followed by laboratory and imaging evalutions. It is difficult to obtain an exact history and physical findings from infants and children. Primary imaging of an abdominal emergency in children is a radiograph of the abdomen. In the case of imaging evalution, ultrasound plays an important role in the diagnosis of pediatric acute abdomen. The common causes of acute abdominal pain in children are intussusception, acute appendicitis, and gastroenteritis. The other causes of abdominal pain are choledochal cyst, midgut malrotation, hemorrhagic colitis, and Henoch-Schönlein purpura. High sensitivity and specificity of ultrasound in the diagnosis of intussusception are established, and sonographic reduction methods of hydrostatic enema are increasing. Sonographic reduction can detect not only intussusception but also the presence of a lead point. Acute appendicitis in children can often carry serious complications, i.e., perforation, abscess formation, and peritonitis, especially if the diagnosis is missed. The appendiceal perforation rate is higher in younger children. The diagnostic accuracy of sonography in the diagnosis of intussusception and acute appendicitis in children has become increasingly high. Ultrasound can easily detect the long segmental wall thickening of the intestinal loop, and the wall thickening may suggest hemorrhagic colitis or Henoch-Schönlein purpura. This article details the sonographic findings of these diseases, especially intussusception, acute appendicitis, hemorrhagic colitis, Henoch-Schönlein purpura, midgut malrotation, and choledochal cyst.