During pregnancy, the umbilical cord passes through a small opening in the baby's abdominal muscles. The opening normally closes just after birth. If the muscles don't join together completely in the midline of the abdomen, this weakness in the abdominal wall may cause an umbilical hernia at birth or later in life.
Ileus may also be caused by an infection inside the abdomen, such as appendicitis or diverticulitis. Disorders outside the intestine, such as kidney failure, an underactive thyroid gland, or abnormal levels of blood electrolytes (low potassium levels or high calcium levels, for example), may cause ileus.
It also can result from certain drugs, spinal injuries, inflammation anywhere within the abdomen that touches the intestines, and diseases of the intestinal muscles themselves. Irrespective of the cause, ileus causes constipation, abdominal distention, and nausea and vomiting. On listening to the abdomen with a stethoscope, few or no bowel sounds are heard (because the bowel is inactive). Also called paralytic ileus. Also simply called ileus.