This chapter discusses the diagnosis, evaluation and management of small bowel obstruction (SBO). It details the specific types of small bowel obstruction. Common causes of small bowel obstruction include hernias, neoplasms, intussusception, and others. Thorough history should be taken, with particular attention paid to prior SBOs, abdominal surgeries, hernias, cancer, and opiate use. The vital signs of SBO are: fever, tachycardia, hypotension, and tachypnea. The examination of the abdomen is performed by visually inspecting the abdomen for scars and distension. Rectal examination is considered with evaluation for occult blood, although diagnostic yield may below and classically the rectal vault will be empty. In laboratory evaluation findings are not specific to bowel obstruction. Results may show evidence of dehydration, acidosis, renal failure, and leukocytosis. Antibiotics are indicated with evidence of ischemia, perforation, or severe disease, although there is no good evidence supporting or refuting the use of empiric broad-spectrum antibiotics.

Plain film radiographs of the pediatric abdomen ordered from the ED are indicated in stable patients to provide contributory information in the diagnostic process of abdominal health complaints. The criteria for distinguishing a bowel obstruction from an ileus include roughly four findings: gas distribution, bowel distention, air fluid levels and orderliness. The differential diagnosis of a bowel obstruction can be remembered with the mnemonic A-A-I-I-M-M, (adhesions, appendicitis, incarcerated hernia, intussusception, malrotation (with midgut volvulus), and Meckel's diverticulum (with a volvulus or intussusception)). A sigmoid occurs more often in elderly patients, whereas a midgut volvulus is a true surgical emergency. Plain film radiographs have a limited role in diagnosing appendicitis. It can be highly diagnostic of intussusception. Abdominal foreign bodies are usually not visible on plain film radiographs, with the exception of metallic and calcific foreign bodies. Uric acid and most calcium oxalate stone are not radiopaque on plain film radiographs.