gastrointestinal disorders
Overview of Gastroenteritis
Etiology of Gastroenteritis
Infectious gastroenteritis may be caused by viruses, bacteria, or parasites. Many specific organisms are discussed further in theInfectious Diseases section. Viruses are the most common cause of gastroenteritis in the United States, and most viral gastroenteritis is caused by Norovirus Gastroenteritis None Rotavirus Gastroenteritis None Most other viral gastroenteritis infections are caused by astrovirus or enteric adenovirus. Astroviruscan infect people of all ages but usually infects infants and young children. In temperate climates, infection is most common in winter months, and in tropical regions, infection is more common in summer months. Transmission is by the fecal-oral route. Incubation is 3 to 4 days. Adenovirus Infections are the 4th most common cause of childhood viral gastroenteritis. Infections occur year-round, with a slight increase in summer. Children Viruses infect enterocytes in the villous epithelium of the small bowel. The result is transudation of fluid and electrolytes into the intestinal lumen; sometimes, unabsorbed carbohydrates resulting from Overview of Malabsorption in the affected bowel subsequently worsen symptoms by causing osmotic diarrhea. Diarrhea is watery. Inflammatory diarrhea (dysentery), with fecal white blood cells (WBCs) and red blood cells (RBCs) or gross blood, is uncommon. In patients with immunocompromise, additional viruses (eg, Cytomegalovirus (CMV) Infection , The bacteria most commonly implicated are Campylobacter and Related Infections None Overview of Clostridial Infections None Escherichia coli Infections (especially Overview of Salmonella Infections None Shigellosis None Staphylococci, causing Staphylococcal food poisoning None Bacterial gastroenteritis is less common than viral. Bacteria cause gastroenteritis by several mechanisms. ) that adhere to intestinal mucosa without invading. These toxins impair intestinal absorption and cause secretion of electrolytes and water by stimulating adenylate cyclase, resulting in watery diarrhea. Overview of Clostridial Infections produces a similar toxin. that are ingested in contaminated food are produced by some bacteria (eg, Staphylococcal Infections , occurs with other bacteria (eg, Shigellosis , SalmonellaandCampylobacterare common bacterial causes of diarrheal illness in the United States. Both infections are most frequently acquired through undercooked poultry; unpasteurized milk is also a possible source.Campylobacteris occasionally transmitted from dogs or cats with diarrhea.Salmonellacan be transmitted by consuming undercooked eggs and by contact with reptiles, birds, or amphibians. type 1, which is rare in the United States ( Bacterial gastroenteritis references ) produces Shiga toxin, which can cause E. coli Gastroenteritis can be caused by several different subtypes of the bacteria. The epidemiology and clinical manifestations vary greatly depending on the subtype. In the past, Overview of Clostridial Infections infection occurred almost exclusively in hospitalized patients receiving antibiotics. With the emergence of the hypervirulent NAP1 strain in the United States in the late 2000s, many community-associated cases are now occurring. C. difficileis now probably the most common bacterial cause of diarrhea in the United States. Several other bacteria cause gastroenteritis, but most are uncommon in the United States. Plague and Other Yersinia Infections can cause gastroenteritis or a syndrome that mimics appendicitis because patients may have pain in the right lower quadrant. It is transmitted by undercooked pork, unpasteurized milk, or contaminated water. Several 1.Centers for Disease Control and Prevention (CDC): Shigella—Shigellosis: Questions & Answers. Accessed May 12, 2023. 2.Johnson S, Lavergne V, Skinner AM, et al: Clinical practice guideline by the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA): 2021 focused update guidelines on management ofClostridioides difficileinfection in adults.Clin Infect Disciab549, 2021. doi: 10.1093/cid/ciab549 The parasites most commonly implicated in high-resource countries are Giardiasis None Cryptosporidiosis None ), adhere to the intestinal mucosa, causing nausea, vomiting, diarrhea, and general malaise. Giardiasis occurs in every region of the United States and throughout the world. The infection can become chronic and may cause a Overview of Malabsorption . It is usually acquired via person-to-person transmission (often in day care centers) or from ingestion of cysts in contaminated water or food. Cryptosporidium parvumcauses watery diarrhea and can sometimes be accompanied by abdominal cramps, nausea, and vomiting. In healthy people, the illness is self-limited, lasting about 2 weeks. In patients with immunocompromise, illness may be severe and prolonged, causing substantial electrolyte and fluid loss.Cryptosporidiumis usually acquired through contaminated water. It is not easily killed by chlorine and is the most common cause of recreational waterborne illness in the United States, accounting for about three fourths of outbreaks. Other parasites that can cause symptoms similar to those of cryptosporidiosis include Cyclosporiasis and, in patients with immunocompromise, 