Gastroenteritis, also known as infectious diarrhea, is an inflammation of the gastrointestinal tract including the stomach and intestine.[ Although it is not related to influenza, in the United States it is sometimes called the " stomach flu".]
Gastroenteritis is usually caused by viruses;[ Treatment is generally the same with or without a definitive diagnosis, so testing to confirm is usually not needed.][
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For young children in impoverished countries, prevention includes hand washing with soap, drinking clean water, breastfeeding babies instead of using infant formula,[ and proper disposal of human waste. The rotavirus vaccine is recommended as a prevention for children.][ Treatment involves getting enough fluids.][ For mild or moderate cases, this can typically be achieved by drinking oral rehydration solution (a combination of water, salts and sugar).][ In those who are breastfed, continued breastfeeding is recommended.][ For more severe cases, intravenous fluids may be needed.][ Fluids may also be given by a nasogastric tube.][
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In 2015, there were two billion cases of gastroenteritis, resulting in 1.3 million deaths globally.
Signs and symptoms
Gastroenteritis usually involves both diarrhea and vomiting.[ Sometimes, only one or the other is present.][ This may be accompanied by abdominal cramps.][ Signs and symptoms usually begin 12–72 hours after contracting the infectious agent.][ Some viral infections also involve fever, fatigue, headache and myalgia.][ If the dysentery, the cause is less likely to be viral][ and more likely to be bacterial.][ Some bacterial infections cause severe abdominal pain and may persist for several weeks.][
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Children infected with rotavirus usually make a full recovery within three to eight days.[ This is called "prolonged capillary refill" and "poor skin turgor".][ Abnormal breathing is another sign of severe dehydration.][ Stunted growth and long-term cognitive delays can result.][
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Reactive arthritis occurs in 1% of people following infections with Campylobacter species.[ Guillain–Barré syndrome occurs in 0.1%.][ Hemolytic uremic syndrome (HUS) may occur due to infection with Shiga toxin-producing Escherichia coli or Shigella species.][ HUS causes thrombocytopenia, renal failure, and hemolytic anemia.][ Some viral infections may produce benign infantile seizures.][
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Cause
Viruses (particularly rotavirus (in children) and norovirus (in adults)) and the bacteria Escherichia coli and Campylobacter species are the primary causes of gastroenteritis.[ There are, however, many other infectious agents that can cause this syndrome including parasites and fungus.][ Non-infectious causes are seen on occasion, but they are less likely than a viral or bacterial cause.][ Risk of infection is higher in children due to their lack of immunity.][ Children are also at higher risk because they are less likely to practice good hygiene habits.][ Children living in areas without easy WASH are especially vulnerable.][
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Viral
, , , and are known to cause viral gastroenteritis.[ and produces similar rates in both the developed world and developing world.][ Viruses cause about 70% of episodes of infectious diarrhea in the pediatric age group.][ Rotavirus is a less common cause in adults due to acquired immunity.]
Norovirus is the leading cause of gastroenteritis among adults in America accounting for about 90% of viral gastroenteritis outbreaks.[ These localized typically occur when groups of people spend time proximate to each other, such as on cruise ships,][ in hospitals, or in restaurants.][ People may remain infectious even after their diarrhea has ended.][ Norovirus is the cause of about 10% of cases in children.][
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Bacterial
In some countries, Campylobacter jejuni is the primary cause of bacterial gastroenteritis, with half of these cases associated with exposure to poultry.[ If food becomes contaminated with bacteria and remains at room temperature for several hours, the bacteria multiply and increase the risk of infection in those who consume the food.][ Some foods commonly associated with illness include raw or undercooked meat, poultry, seafood, and eggs; raw sprouts; unpasteurized milk and soft cheeses; and fruit and vegetable juices.]
Toxigenic Clostridioides difficile is an important cause of diarrhea that occurs more often in the elderly.[ Infants can carry these bacteria without developing symptoms.][ It is a common cause of diarrhea in those who are hospitalized and is frequently associated with antibiotic use.][
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Parasitic
A number of parasites can cause gastroenteritis.[ Giardia lamblia is most common, but Entamoeba histolytica, Cryptosporidium spp., and other species have also been implicated.][
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Transmission
Transmission may occur from drinking contaminated water or when people share personal objects.[ Water quality typically worsens during the rainy season and outbreaks are more common at this time.][ In Temperateness, infections are more common in the winter.][ Worldwide, bottle-feeding of babies with improperly sanitized bottles is a significant cause.][ Transmission rates are also related to poor hygiene, (especially among children),][ in crowded households,][ Adults who have developed immunities might still carry certain organisms without exhibiting symptoms.][ Thus, adults can become natural reservoirs of certain diseases.][ While some agents (such as Shigella) only occur in primates, others (such as Giardia) may occur in a wide variety of animals.][
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Non-infectious
There are a number of non-infectious causes of inflammation of the gastrointestinal tract.[ Some of the more common include medications (like NSAIDs), certain foods such as lactose (in those who are intolerant), and gluten (in those with Coeliac disease). Crohn's disease is also a non-infectious cause of (often severe) gastroenteritis.][ Disease secondary to may also occur. Some food-related conditions associated with nausea, vomiting, and diarrhea include: Ciguatera due to consumption of contaminated predatory fish, scombroid associated with the consumption of certain types of spoiled fish, tetrodotoxin poisoning from the consumption of puffer fish among others, and botulism typically due to improperly preserved food.]
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 bowel 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).][
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Diagnosis
Gastroenteritis is typically diagnosed clinically, based on a person's signs and symptoms.[ Determining the exact cause is usually not needed as it does not alter the management of the condition.][
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However, should be performed in those with blood in the stool, those who might have been exposed to food poisoning, and those who have recently traveled to the developing world.[ It may also be appropriate in children younger than 5, old people, and those with poor immune function.][ As hypoglycemia occurs in approximately 10% of infants and young children, measuring serum glucose in this population is recommended.][ Electrolytes and creatinine should also be checked when there is a concern about severe dehydration.][
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Dehydration
A determination of whether or not the person has dehydration is an important part of the assessment, with dehydration typically divided into mild (3–5%), moderate (6–9%), and severe (≥10%) cases.[ In children, the most accurate signs of moderate or severe dehydration are a prolonged capillary refill, poor skin turgor, and abnormal breathing.][ A normal urinary output and oral fluid intake is reassuring.][ Laboratory testing is of little clinical benefit in determining the degree of dehydration.][ Thus the use of urine testing or ultrasounds is generally not needed.]
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.[ Pancreatic insufficiency, short bowel syndrome, Whipple's disease, coeliac disease, and laxative abuse should also be considered.][
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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.][
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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.[ Personal hygiene measures (such as hand washing with soap) have been found to decrease rates of gastroenteritis in both the developing and developed world by as much as 30%.][ Alcohol-based gels may also be effective.][ Food or drink that is thought to be contaminated should be avoided.][ Breast milk reduces both the frequency of infections and their duration.][
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Vaccination
Due to both its effectiveness and safety, in 2009 the World Health Organization recommended that the rotavirus vaccine be offered to all children globally.[ In Africa and Asia these vaccines reduced severe disease among infants][ and countries that have put in place national immunization programs have seen a decline in the rates and severity of disease.][ The Cholera vaccine has been found to be 50–60% effective over two years.]
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.[ The preferred treatment in those with mild to moderate dehydration is oral rehydration therapy (ORT).]
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.[ Plain water may be used if more specific ORT preparations are unavailable or the person is not willing to drink them.][ A nasogastric tube can be used in young children to administer fluids if warranted.][ In those who require intravenous fluids, one to four hours' worth is often sufficient.]
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.[ Children should continue their usual diet during episodes of diarrhea with the exception that foods high in should be avoided.][ The BRAT diet (bananas, rice, applesauce, toast and tea) is no longer recommended, as it contains insufficient nutrients and has no benefit over normal feeding.][
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A Cochrane Review from 2020 concludes that make little or no difference to people who have diarrhea lasting 2 days or longer and that there is no proof that they reduce its duration.
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.][
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Antibiotics
Antibiotics are not usually used for gastroenteritis, although they are sometimes recommended if symptoms are particularly severe[ Pseudomembranous colitis, usually caused by antibiotic use, is managed by discontinuing the causative agent and treating it with either metronidazole or vancomycin.][ In those with Giardia species or Entamoeba histolytica, tinidazole treatment is recommended and superior to metronidazole.][
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Antimotility agents
Antimotility medication has a theoretical risk of causing complications, and although clinical experience has shown this to be unlikely,[
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Epidemiology
for diarrhea per 100,000 inhabitants in 2004
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It is estimated that there were two billion cases of gastroenteritis that resulted in 1.3 million deaths globally in 2015.[ Children and those in the developing world are most commonly affected.][ As of 2011, in those younger than five, there were about 1.7 billion cases resulting in 0.7 million deaths,][ with most of these occurring in the world's poorest nations.][ More than 450,000 of these fatalities are due to rotavirus in children under five years of age.][ In the developing world, children less than two years of age frequently get six or more infections a year that result in significant gastroenteritis.][ It is less common in adults, partly due to the development of acquired immunity.][
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In 1980, gastroenteritis from all causes caused 4.6 million deaths in children, with the majority occurring in the developing world.[ and approximately ten thousand deaths annually,][ with 150 to 300 of these deaths in children less than five years of age.][
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Society and culture
Gastroenteritis is associated with many colloquial names, including "Montezuma's revenge", "Delhi belly", "la turista", and "back door sprint", among others.[ It has played a role in many military campaigns and is believed to be the origin of the term "no guts no glory".][
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Gastroenteritis is the main reason for 3.7 million visits to physicians a year in the United States[ and 3 million visits in France.][
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Terminology
The first usage of "gastroenteritis" was in 1825.[ Rudy's List of Archaic Medical Terms ] 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.
Some agents are more specific to a certain species. Transmissible gastroenteritis coronavirus (TGEV) occurs in pigs resulting in vomiting, diarrhea, and dehydration.
See also
Notes
External links
