Radiation Effects on Human Gastrointestinal Tract

           The gastrointestinal syndrome describes the effects of radiation poisoning on the stomach and intestine. Radiation with doses of 200 rems or more will cause gastrointestinal syndrome within first hour after exposure. The radiation will damage the gastrointestinal tract lining which leads to nausea, bloody vomiting, abdominal pain, diarrhea and poor appetite. This first phase may last for a few days and follow by a syndrome-free period. As the radiation continues to destroy the cells of the intestinal tract, the shedding of the dead cells will cause bloody diarrhea and severe dehydration. In addition, the blood vessels in the colon and rectum will bleed easily which also causing bloody stool. At this point, radiation begins to destroy the cells that multiply quickly. 

          The most radiation sensitive organ within the gastrointestinal tract is small intestine. It is the organ which will determine the survival of a person with an acute massive attack of radiation. In a healthy individual, the lining cells of the small intestine are constant replace by crypt cells. With acute dose of radiation, inflammation of the small intestine can occur along with scaring and blockage of the small intestine. The crypt cells are killed and the lining of the small intestine ruptures. The loss of cells leads to digestive tract vulnerable to bacteria which can cause life-threatening infections. Once the digestive system ceases to function, death can result within a few weeks due to loss of fluid and electrolytes or infection.