Gastroenteritis

Gastroenteritis usually involves both diarrhea and vomiting. However, in poor countries treatment for severe infections is often out of reach and persistent diarrhea is common. Dehydration is a common complication of diarrhea. Severe dehydration in children may be recognized if the skin color and position returns slowly when pressed. Repeat infections are typically seen in areas with poor sanitation, and malnutrition. Children are more predisposed to getting HUS than adults. Some viral infections may produce benign infantile seizures. ==Cause==

Viruses (particularly rotavirus (in children) and norovirus (in adults)) and the bacteria Escherichia coli and Campylobacter species are the primary causes of gastroenteritis. Rotavirus is the most common cause of gastroenteritis in children, Norovirus is the cause in about 18% of all cases. Generally speaking, viral gastroenteritis accounts for 21–40% of the cases of infectious diarrhea in developed countries. Norovirus is the leading cause of gastroenteritis among adults in America accounting for about 90% of viral gastroenteritis outbreaks. In children, bacteria are the cause in about 15% of cases, with the most common types being Escherichia coli, Salmonella, Shigella, and Campylobacter species. In the developing world, especially sub-Saharan Africa and Asia, cholera is a common cause of gastroenteritis.2 antagonists. It occurs more commonly in persons who have traveled to areas with high prevalence, children who attend day care, men who have sex with men, and following disasters. and in those with poor nutritional status. In the United States, rates of emergency department use for noninfectious gastroenteritis dropped 30% from 2006 until 2011. Of the twenty most common conditions seen in the emergency department, rates of noninfectious gastroenteritis had the largest decrease in visits in that time period. ==Pathophysiology==

Gastroenteritis is defined as vomiting or diarrhea due to inflammation of the small or large bowel, often due to infection. The changes in the small bowel are typically noninflammatory, while the ones in the large bowel are inflammatory. The number of pathogens required to cause an infection varies from as few as one (for Cryptosporidium) to as many as 108 (for Vibrio cholerae). ==Diagnosis==

Gastroenteritis is typically diagnosed clinically, based on a person's signs and symptoms. Diagnostic testing may also be done for surveillance. Other useful findings (when used in combination) include sunken eyes, decreased activity, a lack of tears, and a dry mouth. Differential diagnosis Other potential causes of signs and symptoms that mimic those seen in gastroenteritis that need to be ruled out include appendicitis, volvulus, inflammatory bowel disease, urinary tract infections, and diabetes mellitus. The differential diagnosis can be complicated somewhat if the person exhibits only vomiting or diarrhea (rather than both). Appendicitis may present with vomiting, abdominal pain, and a small amount of diarrhea in up to 33% of cases. This is in contrast to the large amount of diarrhea that is typical of gastroenteritis. Infections of the lungs or urinary tract in children may also cause vomiting or diarrhea. Classical diabetic ketoacidosis (DKA) presents with abdominal pain, nausea, and vomiting, but without diarrhea. One study found that 17% of children with DKA were initially diagnosed as having gastroenteritis. ==Prevention==

Water, sanitation, hygiene A supply of easily accessible uncontaminated water and good sanitation practices are important for reducing rates of infection and clinically significant gastroenteritis. Breastfeeding is important, especially in places with poor hygiene, as is improvement of hygiene generally. Two commercial rotavirus vaccines exist and several more are in development. This vaccine may also prevent illness in non-vaccinated children by reducing the number of circulating infections. Since 2000, the implementation of a rotavirus vaccination program in the United States has substantially decreased the number of cases of diarrhea by as much as 80 percent. The first dose of vaccine should be given to infants between 6 and 15 weeks of age. There are a number of vaccines against gastroenteritis in development. For example, vaccines against Shigella and enterotoxigenic Escherichia coli (ETEC), which are two of the leading bacterial causes of gastroenteritis worldwide. ==Management==

Gastroenteritis is usually an acute and self-limiting disease that does not require medication. and butylscopolamine is useful in treating abdominal pain. Rehydration The primary treatment of gastroenteritis in both children and adults is rehydration. This is preferably achieved by drinking rehydration solution, although intravenous delivery may be required if there is a decreased level of consciousness or if dehydration is severe. Drinking replacement therapy products made with complex carbohydrates (i.e. those made from wheat or rice) may be superior to those based on simple sugars. Drinks especially high in simple sugars, such as soft drinks and fruit juices, are not recommended in children under five years of age as they may increase diarrhea. Dietary It is recommended that breast-fed infants continue to be nursed in the usual fashion, and that formula-fed infants continue their formula immediately after rehydration with ORT. Lactose-free or lactose-reduced formulas usually are not necessary. They may be useful in preventing and treating antibiotic associated diarrhea. Fermented milk products (such as yogurt) are similarly beneficial. Zinc supplementation appears to be effective in both treating and preventing diarrhea among children in the developing world. Antiemetics Antiemetic medications may be helpful for treating vomiting in children. Ondansetron has some utility, with a single dose being associated with less need for intravenous fluids, fewer hospitalizations, and decreased vomiting. Metoclopramide might also be helpful. However, the use of ondansetron might possibly be linked to an increased rate of return to hospital in children. The intravenous preparation of ondansetron may be given orally if clinical judgment warrants. Dimenhydrinate, while reducing vomiting, does not appear to have a significant clinical benefit. or if a susceptible bacterial cause is isolated or suspected. If antibiotics are to be employed, a macrolide (such as azithromycin) is preferred over a fluoroquinolone due to higher rates of resistance to the latter. Salmonella typhi, and Giardia species. The World Health Organization (WHO) recommends the use of antibiotics in young children who have both bloody diarrhea and fever. Loperamide, an opioid analogue, is commonly used for the symptomatic treatment of diarrhea. Loperamide is not recommended in children, however, as it may cross the immature blood–brain barrier and cause toxicity. Bismuth subsalicylate, an insoluble complex of trivalent bismuth and salicylate, can be used in mild to moderate cases, but salicylate toxicity is theoretically possible. ==Epidemiology==

for diarrhea per 100,000 inhabitants in 2004 It is estimated that there were two billion cases of gastroenteritis that resulted in 1.3 million deaths globally in 2015. Cholera causes about three to five million cases of disease and kills approximately 100,000 people yearly. Death rates were reduced significantly (to approximately 1.5 million deaths annually) by 2000, largely due to the introduction and widespread use of oral rehydration therapy. In the US, infections causing gastroenteritis are the second most common infection (after the common cold), and they result in between 200 and 375 million cases of acute diarrhea and approximately ten thousand deaths annually, with 150 to 300 of these deaths in children less than five years of age. ==Society and culture==

Gastroenteritis is associated with many colloquial names, including "Montezuma's revenge", "Delhi belly", "la turista", and "back door sprint", among others. In the United States gastroenteritis as a whole is believed to result in costs of US$23 billion per year, with rotavirus alone resulting in estimated costs of US$1 billion a year. == Terminology ==

The first usage of "gastroenteritis" was in 1825. Before this time it was commonly known as typhoid fever or "cholera morbus", among others, or less specifically as "griping of the guts", "surfeit", "flux", "colic", "bowel complaint", or any one of several other archaic names for acute diarrhea. Cholera morbus is a historical term that was used to refer to gastroenteritis rather than specifically cholera. ==Animals==

Many of the same agents cause gastroenteritis in cats and dogs as in humans. The most common organisms are Campylobacter, Clostridioides difficile, Clostridium perfringens, and Salmonella. A large number of toxic plants may also cause symptoms. Some agents are more specific to a certain species. Transmissible gastroenteritis coronavirus (TGEV) occurs in pigs resulting in vomiting, diarrhea, and dehydration. It is believed to be introduced to pigs by wild birds and there is no specific treatment available. It is not transmissible to humans. ==See also==