Cancer, scar tissue, twisting of the intestine, severe constipation and a variety of diseases can cause a bowel blockage, also known as a bowel obstruction, according to WebMD. Causes often differ depending on whether the blockage occurs in the small or large intestine.
In the large intestine, frequent causes of bowel obstructions include diseases that narrow the intestines, such as diverticulitis and inflammatory bowel disease, WebMD states. Hard stool masses created by severe constipation can also block the large intestine.
The most common causes of blockages in the small intestine are scar tissue or tumors, WebMD reports. Crohn's disease and hernias can also twist the small intestine, resulting in a blockage. Another type of folding, called an intussusception, can also obstruct the small intestine. An intussusception is when the bowel collapses into itself, similar to folding and unfolding a telescope.
A bowel blockage often causes pain that comes and goes, WebMD explains. The diagnosis includes both complete and partial obstructions. When the bowel is blocked, gas, fluids and food cannot pass through the intestines. Other symptoms include vomiting, a hard belly and bloating. If the intestine is completely blocked, patients may notice the lack of gas and constipation. If it is partially blocked, patients may experience diarrhea.