Bowel obstruction occurs when the normal passage of intestinal contents is blocked, either mechanically (adhesions, hernias, tumors, volvulus, intussusception) or functionally (ileus). Ultrasound can diagnose bowel obstruction with high sensitivity and specificity, demonstrating dilated, fluid-filled bowel loops (>25 mm for small bowel), the ‘to-and-fro’ peristaltic pattern, and, in experienced hands, identifying the transition point. Ultrasound avoids radiation and is particularly valuable in pregnant patients or children. The sonographer looks for a central distribution of dilated loops, presence of valvulae conniventes (small bowel) versus haustra (large bowel), and signs of strangulation (thickened wall, absent peristalsis, free fluid).
Associated Anatomy: Small Intestine, Large Intestine
Signs & Symptoms: Crampy abdominal pain, abdominal distension, nausea, vomiting, failure to pass gas or stool
ICD-10: K56