gastroenteritis n : inflammation of the stomach and intestines; can be caused by Salmonella enteritidis [syn: stomach flu, intestinal flu]

English

Noun

1. inflammation of the mucous membranes of the stomach and intestine; often caused by an infection

Gastroenteritis (also known as gastro, gastric flu, and stomach flu although unrelated to influenza) refers to inflammation of the gastrointestinal tract, involving both the stomach and the small intestine (see also gastritis and enteritis) and resulting in acute diarrhea. The inflammation is caused most often by infection with certain viruses, less often by bacteria or their toxins, parasites, or adverse reaction to something in the diet or medication. Worldwide, inadequate treatment of gastroenteritis kills 5 to 8 million people per year, and is a leading cause of death among infants and children under 5.

At least 50% of cases of gastroenteritis as foodborne illness are due to norovirus. Another 20% of cases, and the majority of severe cases in children, are due to rotavirus. Other significant viral agents include adenovirus and astrovirus.

Many different bacteria can cause gastroenteritis, including Salmonella, Shigella, Staphylococcus, Campylobacter jejuni, Clostridium, Escherichia coli, Yersinia, and others. Some sources of the infection are improperly prepared food, reheated meat dishes, seafood, dairy, and bakery products. Each organism causes slightly different symptoms but all result in diarrhea. Colitis, inflammation of the large intestine, may also be present.

Risk factors are consumption of improperly prepared foods or contaminated water and travel or residence in areas of poor sanitation. The incidence is 1 in 1,000 people.

Epidemiology

Globally, gastroenteritis caused 4.6 million deaths in children in 1980 alone, most of these in the developing world,

The incidence in the developed countries is as high as 1-2.5 cases per child per year and a major cause of hospitalisation in this age group.

Age, living conditions, hygiene and cultural habits are important factors. Aetiological agents vary depending on the climate. Furthermore, most cases of gastroenteritis are seen during the winter in temperate climates and during summer in the tropics. Historians, genealogists, and other researchers should keep in mind that gastroenteritis was not considered a discrete diagnosis until fairly recently.

Symptoms and signs

It often involves stomach pain or spasms (sometimes to the point of being crippling), diarrhea and/or vomiting, with noninflammatory infection of the upper small bowel, or inflammatory infections of the colon.

It usually is of acute onset, normally lasting fewer than 10 days and self-limiting.

• Nausea and vomiting
• Diarrhea
• Loss of appetite
• Abdominal pain
• Abdominal cramps
• Bloody stools (dysentery - suggesting infection by amoeba, Campylobacter, Salmonella, Shigella or some pathogenic strains of Escherichia coli)
• Fainting and Weakness

The main contributing factors include poor feeding in infants. Diarrhea is common, and may be (but not always) followed by vomiting. Viral diarrhea usually causes frequent watery stools, whereas blood stained diarrhea may be indicative of bacterial colitis. In some cases, even when the stomach is empty, bile can be vomited up.

A child with gastroenteritis may be lethargic, suffer lack of sleep, or run a low fever and have signs of dehydration, which include dry mucous membranes, tachycardia, reduced skin turgor, skin color discoloration, sunken fontanelles and sunken eyeballs and darkened eye circles, glassy eyes,poor perfusion and ultimately shock.

Symptoms occur for up to 6 days on average. Given appropriate treatment, bowel movements will return to normal within a week after that.

Signs and Tests

• Stool culture positive for the organism that causes the infection
• White blood cells in the stool
• Examination of food for toxin and bacteria

This disease may also alter the results of the following tests:

• Stool gram stain
• Fecal smear

Differential diagnosis

It is important to consider infectious gastroenteritis as a diagnosis per exclusionem. A few loose stools and vomiting may be the result of systemic infection such as pneumonia, septicemia, urinary tract infection and even meningitis. Surgical conditions such as appendicitis, intussusception and, rarely, even Hirschsprung's disease may mislead the clinician.

Non-infectious causes to consider are poisoning with heavy metals (e.g. arsenic, cadmium), seafood (e.g. ciguatera, scombroid, toxic encephalopathic shellfish poisoning) or mushrooms (e.g. Amanita phalloides). Secretory tumours (e.g. carcinoid, medullary tumour of the thyroid, vasoactive intestinal peptide-secreting adenomas) and endocrine disorders (e.g. thyrotoxicosis and Addison's disease) are disorders that can cause diarrhea. Also, pancreatic insufficiency, short bowel syndrome, Whipple's disease, coeliac disease, and laxative abuse should be excluded as possibilities. Children admitted to hospital with gastroenteritis routinely are tested for rotavirus A to gather surveillance data relevant to the epidemiological effects of rotavirus vaccination programs. These children are routinely tested also for norovirus, which is extraordinarily infectious and requires special isolation procedures to avoid transmission to other patients. Other methods, electron microscopy and polyacrylamide gel electrophoresis, are used in research laboratories.

Treatment

The objective of treatment is to replace lost fluids and electrolytes. The person's usual foods and drinks should not be withheld, but consumed as the person is able to tolerate them.

Rehydration

Regardless of cause, the principal treatment of gastroenteritis (and of all other diarrheal illnesses) in both children and adults is rehydration, i.e. replenishment of water lost in the stools. Depending on the degree of dehydration, this can be done by giving the person oral rehydration therapy (ORT) or through intravenous delivery. ORT can begin before dehydration occurs, and continue until the person's urine and stool output return to normal.

People taking diuretics ("water pills") need to be cautious with diarrhea and may need to stop taking the medication during an acute episode, as directed by the health care provider.

Dietary therapy

Centers for Disease Control and Prevention recommendations for infants and children include: Breastfed infants should continue to be nursed on demand. Formula-fed infants should continue their usual formula immediately upon rehydration in amounts sufficient to satisfy energy and nutrient requirements, and at the usual concentration. Lactose-free or lactose-reduced formulas usually are unnecessary. Children receiving semisolid or solid foods should continue to receive their usual diet during episodes of diarrhea. Foods high in simple sugars should be avoided because the osmotic load might worsen diarrhea; therefore, substantial amounts of soft drinks (carbonated or flat), juice, gelatin desserts, and other highly sugared liquids should be avoided. Fatty foods should not be avoided, because maintaining adequate calories without fat is difficult, and fat might have an added benefit of reducing intestinal motility. The practice of withholding food for more than 24 hours is inappropriate.

Probiotics

Probiotics have been shown to be beneficial in preventing and treating various forms of gastroenteritis.

Zinc

The World Health Organization recommends that infants and children receive a dietary supplement of zinc for up to 2 weeks after onset of gastroenteritis.

Drug therapy

Antibiotics

When the symptoms are severe one usually starts empirical antimicrobial therapy, i.e. a fluoroquinolone antibiotic.

Antidiarrheal agents

Loperamide is an opioid analogue commonly used for symptomatic treatment of diarrhea. It slows down gut motility, but does not cross the mature blood-brain barrier Although antimotility drugs have the risk of exacerbating the condition, this fear is not supported by clinical experience.

Complications

The most serious complication is dehydration, usually due to severe diarrhea but sometimes made worse due to improper treatment such as withholding fluids until diarrhea stops. Severe dehydration can be lethal and requires prompt medical care. The most common complication, especially in infants, is malabsorption of certain sugars in the diet, and consequent food intolerances. This complication may persist for weeks, during which time it causes mild diarrhea to return when the patient resumes their normal diet. Malabsorption of lactose, the principal sugar in milk, is the most common. Its consequent milk intolerance is caused by lactase deficiency, and the diarrhea is caused by bacterial fermentation of excess lactose in the gut. However, this is not reason to discontinue breastfeeding. In children with viral gastroenteritis (usually rotavirus), the viral infection also can cause a high fever, which in turn can cause febrile convulsion. Gastroenteritis sometimes is followed by pneumonia.

Rare complications of gastroenteritis caused by bacteria include sepsis (treated with antibiotics), anemia, renal (kidney) failure, arthritis, and new onset of irritable bowel syndrome.

See also

• Diarrhea
• 1984 Rajneeshee bioterror attack
• Food poisoning
• Eosinophilic gastroenteritis
• Hemorrhagic gastroenteritis
• Cholera
• Dysentery
• Infectious diarrhea
• Traveler's diarrhea
• Pseudomembranous colitis

References

• Victora, C. G., Bryce, J., Fontaine, O., & Monasch, R. 2000, 'Reducing deaths from diarrhoea through oral rehydration therapy', Bulletin of The World Health Organization, vol. 78, no. 10, pp. 1246-1255.
• Wingate D. et al. 2001. 'Guidelines for adults on self-medication for the treatment of acute diarrhea', Alimentary Pharmacology & Therapeutics, vol. 15, no. 6, pp. 773-782.

External links

• Gastroenteritis: First aid from the Mayo Clinic