Which is an example of a nonmechanical bowel obstruction?

A nonmechanical bowel obstruction, or paralytic ileus, occurs when intestinal peristalsis ceases without a physical barrier. This is frequently triggered by abdominal surgery, electrolyte imbalances, or peritoneal inflammation. The lack of propulsive motility leads to the accumulation of secretions and gas, resulting in functional distention. A. Tumor of the bowel: A neoplasm represents a physical, structural mass that occludes the intestinal lumen. This is classified as a mechanical obstruction because there is a tangible object blocking the passage of contents. Treatment usually requires surgical resection or stenting. B. Paralytic ileus: This condition involves a failure of the enteric nervous system or smooth muscle to coordinate contractions. Because there is no physical lesion or kink, it is categorized as nonmechanical or functional. It often resolves with bowel rest and fluid resuscitation. C. Narrowed bowel lumen: Strictures resulting from Crohn's disease or surgical scarring are physical impediments to flow. These are mechanical causes because the diameter of the tube is structurally compromised. They often require balloon dilation or surgical repair. D. Fecal impaction: A hard mass of stool acts as a physical plug within the rectum or colon. This is a mechanical blockage that must be manually or chemically removed. It is a tangible obstruction of the intestinal pathway.