If there are symptoms, the following may indicate colon cancer: 1  Abdominal pain and tenderness in the lower abdomen. 2  Blood in the stool. 3  Diarrhea, constipation, or other change in bowel habits. 4  Narrow stools. 5  Weight loss with no known reason.
Diarrhea may be caused by: lactose intolerance. bacterial infection. damage to intestinal wall. hormone-producing tumors (including certain types of pancreatic neuroendocrine tumors) inflammation or ulceration of the bowel. malabsorption caused by surgery that has shortened the intestines. pancreatic enzyme insufficiency.
These parasites include flat worms, roundworms, hookworms, and flukes. Visitors usually become infected by eating or drinking something that has been contaminated with the parasites' ova, but some of the parasites can also penetrate the skin. Viruses: Rotavirus is the most common cause of severe diarrhea among children.Other viruses include Norwalk, noroviruses (also called Norwalk-like viruses), adenoviruses, calciviruses, cytomegalovirus (CMV) , and HIV.ommon causes of chronic diarrhea: Chronic diarrhea, diarrhea that lasts for more than a few weeks, sporadic diarrhea, and diarrhea that alternates with constipation are most frequently associated with non-infectious causes of diarrhea.