Enterocolitis is a type of intestinal inflammation. Its causes may be idiopathic, infectious, ischemic, chemical or "miscellaneous". Idiopathic causes are responsible for Crohn's disease and ulcerative colitis. Chemical causes include drugs, chemotherapy, and radiation injury. Miscellaneous causes include diverticular disease, collagenous colitis, lymphocytic collitis and pseudomebranous colitis.
Infectious enterocolitis is a group of diseases of immense global magnitude responsible for an estimated 12 000 deaths every day from dehydration among children in developing countries, and approximately half of all deaths under the age of 5 years. Viral gastroenteritis is most commonly caused by rotavirus, which typically causes vomiting and watery diarrhea in young children. The norwalk virus causes a significant number of cases in older children and adults, most recently in southwestern Ontario.
There are three major mechanisms for the pathogenesis of bacterial enterocolitis: Ingestion of preformed toxin in contaminated food (e.g., Staphylococcus aureus, Vibrios, Clostridium perfringens). These organisms grow on contaminated food and release powerful toxins that, on ingestion, cause food poisoning symptoms without multiplication in the gut. Symptoms develop quickly within hours of ingesting contaminated food and pass off within a day or so.
During infection by toxigenic organisms (e.g., Vibrio cholerae, some Escheria coli), bacteria multiply within the mucous layer overlying the gut mucosa and release toxins. The incubation period varies from several hours to days. During infection by enteroinvasive organisms (e.g., Shigella, Salmonella, Campylobacter, and some E. coli). These bacteria invade and damage the intestinal mucosa causing inflammation, ulceration and hemorrhage. Dysentery (bloody diarrhea) usually results.