Instruct: Given a question, retrieve relevant passages that answer the question.
Query: What is the most common cause of gastroenteritis?
Gastroenteritis, also known as infectious diarrhea, is inflammation of the gastrointestinal tract—the stomach and small intestine. Symptoms may include diarrhea, vomiting, and abdominal pain. Fever, lack of energy, and dehydration may also occur. This typically lasts less than two weeks. It is not related to influenza though it has been called the "stomach flu".
Gastroenteritis is usually caused by viruses. However, bacteria, parasites, and fungus can also cause gastroenteritis. In children, rotavirus is the most common cause of severe disease. In adults, norovirus and "Campylobacter" are common causes. Eating improperly prepared food, drinking contaminated water, or close contact with a person who is infected can spread the disease. Treatment is generally the same with or without a definitive diagnosis, so testing to confirm is usually not needed.
Prevention includes hand washing with soap, drinking clean water, proper disposal of human waste, and breastfeeding babies instead of using formula. 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 breast fed, continued breastfeeding is recommended. For more severe cases, intravenous fluids may be needed. Fluids may also be given by a nasogastric tube. Zinc supplementation is recommended in children. Antibiotics are generally not needed. However, antibiotics are recommended for young children with a fever and bloody diarrhea.
In 2015 two billion cases of gastroenteritis resulted in 1.3 million deaths globally. Children and those in the developing world are affected the most. In 2011, about 1.7 billion cases resulting in about 700,000 deaths of children under the age of five. In the developing world children less than two years of age frequently get six or more infections a year. It is less common in adults, partly due to the development of immunity.
Gastrointestinal surgery can often be performed in the outpatient setting. In the United States in 2012, operations on the digestive system accounted for 3 of the 25 most common ambulatory surgery procedures and constituted 9.1 percent of all outpatient ambulatory surgeries.
Constipation is the most common chronic gastrointestinal disorder in adults. Depending on the definition employed, it occurs in 2% to 20% of the population. It is more common in women, the elderly and children. Specifically constipation with no known cause affects females more often affected than males. The reasons it occurs more frequently in the elderly is felt to be due to an increasing number of health problems as humans age and decreased physical activity.Since ancient times different societies have published medical opinions about how health care providers should respond to constipation in patients. In various times and places, doctors have made claims that constipation has all sorts of medical or social causes. Doctors in history have treated constipation in reasonable and unreasonable ways, including use of a spatula mundani.
This may occur when there is a large mass of feces in the rectum (fecal loading), which may become hardened (fecal impaction). Liquid stool elements are able to pass around the obstruction, leading to incontinence. Megarectum (enlarged rectal volume) and rectal hyposensitivity are associated with overflow incontinence. Hospitalized patients and care home residents may develop FI via this mechanism, possibly a result of lack of mobility, reduced alertness, constipating effect of medication and/or dehydration.
FI is a sign or a symptom, not a diagnosis, and represents an extensive list of causes. Usually, it is the result of a complex interplay of several coexisting factors, many of which may be simple to correct. Up to 80% of people may have more than one abnormality that is contributing. Deficits of individual functional components of the continence mechanism can be partially compensated for a certain period of time, until the compensating components themselves fail. For example, obstetric injury may precede onset by decades, but postmenopausal changes in the tissue strength reduce in turn the competence of the compensatory mechanisms. The most common factors in the development are thought to be obstetric injury and after effects of anorectal surgery, especially those involving the anal sphincters and hemorrhoidal vascular cushions. The majority of incontinent persons over the age of 18 fall into one of several groups: those with structural anorectal abnormalities (sphincter trauma, sphincter degeneration, perianal fistula, rectal prolapse), neurological disorders (multiple sclerosis, spinal cord injury, spina bifida, stroke, etc.), constipation/fecal loading (presence of a large amount of feces in the rectum with stool of any consistency), cognitive and/or behavioral dysfunction (dementia, learning disabilities), diarrhea, inflammatory bowel diseases (e.g. ulcerative colitis, Crohn's disease), irritable bowel syndrome, disability related (people who are frail, acutely unwell, or have chronic/acute disabilities), and those cases which are idiopathic (of unknown cause). Diabetes mellitus is also known to be a cause, but the mechanism of this relationship is not well understood.
CD with "classic symptoms", which include gastrointestinal manifestations such as chronic diarrhea and bloating, malabsorption of certain vitamins and minerals, loss of appetite, impaired growth and even bone pain, is currently the least common presentation form of the disease and affects predominantly to small children generally younger than two years of age.
Acute disease might include infections such as oesophagitis, trauma caused ingestion of corrosive substances, or rupture of veins such as oesophageal varices, Boerhaave syndrome or Mallory-Weiss tears. Chronic diseases might include congenital diseases such as Zenker's diverticulum and esophageal webbing, and oesophageal motility disorders including the nutcracker oesophagus, achalasia, diffuse oesophageal spasm, and oesophageal stricture.
Botulinum toxin produced by "Clostridium botulinum" is the cause of botulism. Humans most commonly ingest the toxin from eating improperly-canned foods in which "C. botulinum" has grown. However, the toxin can also be introduced through an infected wound. In infants, the bacteria can sometimes grow in the intestines and produce botulinum toxin within the intestine and can cause a condition known as floppy baby syndrome. In all cases, the toxin can then spread, blocking nerves and muscle function. In severe cases, the toxin can block nerves controlling the respiratory system or heart, resulting in death.
Similar to Hepatitis A, hepatitis E manifests as large outbreaks and epidemics associated with fecal contamination of water sources. It accounts for more than 55,000 deaths annually with approximately 20 million people worldwide thought to be infected with the virus. It affects predominantly young adults, causing acute hepatitis. In infected pregnant women, Hepatitis E infection can lead to fulminant hepatitis with third trimester mortality rates as high as 30%. Individuals with weakened immune systems, such as organ transplant recipients, are also susceptible. Infection is rare in the United States but rates are high in the developing world (Africa, Asia, Central America, Middle East). Many genotypes exist and are differentially distributed around the world. There is some evidence of hepatitis E infection of animals, serving as a reservoir for human infection.
Burning or gnawing feeling in the stomach area lasting between 30 minutes and 3 hours commonly accompanies ulcers. This pain can be misinterpreted as hunger, indigestion or heartburn. Pain is usually caused by the ulcer but it may be aggravated by the stomach acid when it comes into contact with the ulcerated area. The pain caused by peptic ulcers can be felt anywhere from the navel up to the sternum, it may last from few minutes to several hours and it may be worse when the stomach is empty. Also, sometimes the pain may flare at night and it can commonly be temporarily relieved by eating foods that buffer stomach acid or by taking anti-acid medication. However, peptic ulcer disease symptoms may be different for every sufferer."Helicobacter pylori" is one of the major causative factors of peptic ulcer disease. It secretes urease to create an alkaline environment which is suitable for its survival. It expresses blood group antigen adhesin (BabA) and outer inflammatory protein adhesin (OipA) which enables it to attach to the gastric epithelium. The bacterium also expresses virulence factors such as "CagA" and "PicB" which cause stomach mucosal inflammation. The VacA gene encodes for vacuolating cytotoxin, but its mechanism of causing peptic ulcers is unclear. Such stomach mucosal inflammation can be associated with hyperchlorhydria (increased stomach acid secretion) or hypochlorhydria (reduced stomach acid secretion). Inflammatory cytokines inhibit the parietal cell acid secretion. "H. pylori" also secretes certain products that inhibit hydrogen potassium ATPase, activate calcitonin gene-related peptide sensory neurons which increases somatostatin secretion to inhibit acid production by parietal cells, and inhibit gastrin secretion. This reduction in acid production causes gastric ulcers. On the other hand, increased acid production at the pyloric antrum is associated with duodenal ulcers in 10 to 15% of the "H. pylori" infection cases. In this case, somatostatin production is reduced and gastrin production is increased, leading to increased histamine secretion from the enterochromaffin cells, thus increasing acid production. An acidic environment at the antrum causes metaplasia of the duodenal cells, causing duodenal ulcers.
Many over-the-counter and prescription-only medications contain paracetamol. Because of its wide availability paired with comparably high toxicity, (compared to ibuprofen and aspirin) there is a much higher potential for overdose. Paracetamol toxicity is one of the most common causes of poisoning worldwide. In the United States, the United Kingdom, Australia, and New Zealand, paracetamol is the most common cause of drug overdoses. Additionally, in both the United States and the United Kingdom it is the most common cause of acute liver failure.
Food-borne botulism results, indirectly, from ingestion of food contaminated with Clostridium spores, where exposure to an anaerobic environment allows the spores to germinate, after which the bacteria can multiply and produce toxin. Critically, "it is ingestion of toxin rather than spores or vegetative bacteria" that causes botulism. Botulism is nevertheless known to be transmitted through canned foods not cooked correctly before canning or after can opening, and so is preventable. Infant botulism cases arise chiefly as a result of environmental exposure and are therefore more difficult to prevent. Infant botulism arising from consumption of honey can be prevented by eliminating honey from diets of children less than 12 months old.
Diabetes is a chronic metabolic disease characterized by increase blood glucose level. Type 2 diabetes is the most common form of diabetes. It is caused by resistance to insulin or the lack of production of insulin. It is seen most commonly in adults. Type 1 diabetes or juvenile diabetes affects mostly children. This condition is due to little or lack of insulin production from the pancreas.
A perforated ulcer is a condition in which an untreated ulcer can burn through the wall of the stomach (or other areas of the gastrointestinal tract), allowing digestive juices and food to leak into the abdominal cavity. Treatment generally requires immediate surgery. The ulcer is known initially as a peptic ulcer before the ulcer burns through the full thickness of the stomach or duodenal wall. A diagnosis is made by taking an erect abdominal/chest X-ray (seeking air under the diaphragm). This is in fact one of the very few occasions in modern times where surgery is undertaken to treat an ulcer. Many perforated ulcers have been attributed to the bacterium "Helicobacter pylori". The incidence of perforated ulcer is steadily declining, though there are still incidents where it occurs. Causes include smoking and nonsteroidal anti-inflammatory drugs (NSAIDs). A perforated ulcer can be grouped into a stercoral perforation which involves a number of different things that causes perforation of the intestine wall. The first symptom of a perforated peptic ulcer is usually sudden, severe, sharp pain in the abdomen. The experience is typically so intense that most people precisely recall the exact moment the pain began. The pain is typically at its maximum immediately and persists. It is characteristically made worse by any movement, and greatly intensifies with coughing or sneezing.
In all cases, illness is caused by the botulinum toxin produced by the bacterium "C. botulinum" in anaerobic conditions and not by the bacterium itself. The pattern of damage occurs because the toxin affects nerves that fire (depolarize) at a higher frequency first.
In general, humans can survive for two to eight weeks without food, depending on stored body fat. Survival without water is usually limited to three or four days. About 36 million humans die every year from causes directly or indirectly related to starvation. Childhood malnutrition is also common and contributes to the global burden of disease. However global food distribution is not even, and obesity among some human populations has increased rapidly, leading to health complications and increased mortality in some developed, and a few developing countries. Worldwide over one billion people are obese, while in the United States 35% of people are obese, leading to this being described as an "obesity epidemic." Obesity is caused by consuming more calories than are expended, so excessive weight gain is usually caused by an energy-dense diet.
Canine distemper is caused by a single-stranded RNA virus of the family "Paramyxoviridae" (the same family of the viruses that causes measles, mumps, and bronchiolitis in humans). The disease is highly contagious via inhalation. Morbidity and mortality may vary greatly among animal species, with up to 100% mortality in unvaccinated populations of ferrets. In domestic dogs, while the acute generalized form of distemper has a high mortality rate, disease duration and severity depends mainly on the animal's age and immune status and virulence of the infecting strain of the virus. Despite extensive vaccination in many regions, it remains a major disease of dogs, and was the leading cause of infectious disease death in dogs, prior to a vaccine becoming available.
Swimming in the pool at the bottom of the falls is discouraged. This is due both to occasional rockfalls and to the bacterial disease called Leptospirosis, which causes severe flu-like symptoms. Leptospirosis is found in freshwater and is common in tropical climates. In Hawaii, rats and mice often carry the disease and can easily transfer it to humans through their urine.
In addition, ischemic colitis is a well-recognized complication of abdominal aortic aneurysm repair, when the origin of the inferior mesenteric artery is covered by the aortic graft. In a 1991 review concerning 2137 patients the accidental inferior mesenteric artery ligation was the most common cause (74%) of ischemic colitis. Thus, patients without adequate collateralization are at risk for ischemia of the descending and sigmoid colon. Bloody diarrhea and leukocytosis in the postoperative period are essentially diagnostic of ischemic colitis. The complication can be prevented through careful selection of subjects that may require replanting inferior mesenteric artery (IMA) and completing the pre surgical procedure information with an instrumental evaluation during surgical treatment.
Humans become infected through contact with water, food, or soil that contains urine from these infected animals. This may happen by swallowing contaminated food or water or through skin contact. The disease is not known to spread between humans, and bacterial dissemination in convalescence is extremely rare in humans. Leptospirosis is common among water-sport enthusiasts in specific areas, as prolonged immersion in water promotes the entry of this bacterium. Surfers and whitewater paddlers are at especially high risk in areas that have been shown to contain these bacteria, and can contract the disease by swallowing contaminated water, splashing contaminated water into their eyes or nose, or exposing open wounds to infected water.
In tropical and semi tropical areas, like South and South-east Asia the disease is increasingly seen as epidemics after heavy rains, sometimes after flooding. Periods of heavy rain followed by days of little or no rain seemed to be the setting for leptospirosis epidemics in this part of the world. Most cases seemed to occur by cutaneous exposure of the legs while walking in stagnant water or moist soil. The presence of wounds or fissures on the legs are a risk factor for acquiring the infection.
Gastric acid is one of the main secretions of the stomach. It consists mainly of hydrochloric acid and acidifies the stomach content to a pH of 1 to 2.
Various pathogens can cause gastroenteritis an inflammation of the stomach and small intestine. These can include those organisms that cause foodborne illnesses. Furthermore, antibiotics can decrease the microbiome diversity of the gastrointestinal tract and thus cause inflammation in the area. Gastroenteritis is the most common disease of the GI tract.Diverticular disease is a condition that is very common in older people in industrialized countries. It usually affects the large intestine but has been known to affect the small intestine as well. Diverticulosis occurs when pouches form on the intestinal wall. Once the pouches become inflamed it is known as diverticulitis.
Many of the same agents cause gastroenteritis in cats and dogs as in humans. The most common organisms are "Campylobacter", "Clostridium difficile", "Clostridium perfringens", and "Salmonella". A large number of toxic plants may also cause symptoms.
In the developed world "Campylobacter jejuni" is the primary cause of bacterial gastroenteritis, with half of these cases associated with exposure to poultry. In children, bacteria are the cause in about 15% of cases, with the most common types being "Escherichia coli", "Salmonella", "Shigella", and "Campylobacter" species. If food becomes contaminated with bacteria and remains at room temperature for a period of 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. In the developing world, especially sub-Saharan Africa and Asia, cholera is a common cause of gastroenteritis. This infection is usually transmitted by contaminated water or food.
Rotavirus gastroenteritis is a mild to severe disease characterised by vomiting, watery diarrhoea, and low-grade fever. Once a child is infected by the virus, there is an incubation period of about two days before symptoms appear. Symptoms often start with vomiting followed by four to eight days of profuse diarrhoea. Dehydration is more common in rotavirus infection than in most of those caused by bacterial pathogens, and is the most common cause of death related to rotavirus infection.