Intestinal flu or grippe and some types of traveler's diarrhea may be caused by bacterial enterotoxins or viral infections. Pathophysiology Certain bacterial species elaborate enterotoxins, which impair intestinal absorption and can provoke secretion of electrolytes and water. Some Shigella, Salmonella, and E. coli species penetrate the mucosa of the small intestine or colon and produce microscopic ulceration, bleeding, exudation of protein-rich fluid, and secretion of electrolytes and water. The invasive process and its results may occur whether or not the organism elaborates an enterotoxin. Many drugs, including broad-spectrum antibiotics, have major GI side effects.
Various mechanisms play a role, including the alteration of normal gut flora.
The character and severity of symptoms depend on the nature of the causative agent, the duration of its action, the patient's resistance, and the extent of GI involvement. Associated malaise, muscular aches, and prostration may occur. Excessive vomiting or diarrhea may cause hypokalemia. Hyponatremia may develop, particularly if hypotonic fluids are used in replacement therapy. Severe dehydration and acid-base imbalance can produce headache and muscular and nervous irritability.