A bowel obstruction can occur without a physical (mechanical) blockage of the small or large intestine. A nonmechanical bowel obstruction (also called adynamic ileus or paralytic ileus), is an inability of the intestines to move normally even though there is nothing blocking them.

The most common cause of a nonmechanical bowel obstruction is temporary paralysis of the intestines after abdominal surgery. Other causes include:

• An imbalance of minerals (electrolytes) in the bloodstream.
• Some medicines, including those for high blood pressure (such as diltiazem and verapamil) and narcotic pain medicines (such as morphine).
• Abdominal inflammation from conditions such as appendicitis, pancreatitis, or diverticulitis.
• Loss of blood supply to the tissues that support and cover the abdominal organs (mesenteric ischemia).
• Infection throughout the bloodstream and tissues (sepsis).

Symptoms of a nonmechanical bowel obstruction are similar to those of a mechanical obstruction. You may have abdominal discomfort, bloating (distention), nausea, and vomiting and not be able to pass gas or stools. However, pain from a nonmechanical bowel obstruction generally is less severe and less cramping than pain from a mechanical obstruction.

Treatment for a nonmechanical bowel obstruction begins with IV (intravenous) fluids and electrolytes to keep your blood pressure at a normal level. You are usually not allowed to eat or drink. A tube placed in your nose and into the stomach removes fluids and gas, preventing pain and bloating. In most cases of a blockage that happens after abdominal surgery, intestinal movement returns to normal after 1 to 3 days. If an obstruction remains, you will have tests to find the cause.