Which of the following causes intestinal obstruction?

Intussusception is a condition where a part of the intestine telescopes into an adjacent segment, leading to obstruction. This can cause a block in the normal flow of contents through the intestines. The immediate effect of intussusception is typically pain, vomiting, and possibly distension of the abdomen. It is most commonly seen in children, though adults can also be affected, often as a result of an underlying pathology.

In contrast, colitis primarily refers to inflammation of the colon and may lead to symptoms like diarrhea or abdominal pain, but it does not directly result in an obstruction. Volvulus of the cecum involves twisting of the intestine, which can cause obstruction, but not all cases result in this definitive diagnosis. A superior mesenteric embolus can lead to ischemia and possibly necrosis of the bowel; however, this does not inherently cause mechanical obstruction but may instead complicate intestinal flow. Thus, while several choices can lead to complications within the gastrointestinal tract, intussusception is distinctly characterized as a primary cause of intestinal obstruction.