Gastroenteritis

What is gastroenteritis?

Gastroenteritis is an inflammation of the gastrointestinal tract (the pathway responsible for digestion that includes the mouth, esophagus, stomach, and intestines). Gastroenteritis is also sometimes referred to as stomach flu, even though it may not be related to influenza.

What causes gastroenteritis?

Gastroenteritis can be caused by viral, bacterial, or parasitic infections. Viral gastroenteritis is contagious and is responsible for the majority of outbreaks in developed countries.

Common routes of infection include:

• Food (especially seafood)
• Contaminated water
• Contact with an infected person
• Unwashed hands
• Dirty utensils

In less developed countries, gastroenteritis is more often spread through contaminated food or water.

What are the symptoms of gastroenteritis?

The main symptom of gastroenteritis is diarrhea. When the colon (large intestine) becomes infected during gastroenteritis, it loses its ability to retain fluids, which causes the person's feces to become loose or watery. Other symptoms include:

• Abdominal pain or cramping
• Nausea
• Vomiting
• Fever
• Poor feeding (in infants)
• Unintentional weight loss (may be a sign of dehydration)
• Excessive sweating
• Clammy skin
• Muscle pain or joint stiffness
• Incontinence (loss of stool control)

Because of the symptoms of vomiting and diarrhea, people who have gastroenteritis can become dehydrated quickly. It is very important to watch for signs of dehydration, which include:

• Extreme thirst
• Urine that is darker in color, or less in amount
• Dry skin
• Dry mouth
• Sunken cheeks or eyes
• In infants, dry diapers (for more than 4-6 hours)

How common is gastroenteritis?

Because gastroenteritis is so similar to diarrhea, and because so many cases do not require hospitalization, it is difficult to determine how many cases of gastroenteritis occur per year. Worldwide, it is estimated that 3 to 5 billion cases of acute diarrhea (which can be caused by many other diseases besides gastroenteritis) occur per year. Severe gastroenteritis is estimated to cause about 5 to 10 million deaths per year worldwide.

Who is at risk for gastroenteritis?

Anyone can get the disease. People who are at a higher risk include:

• Children in daycare
• Students living in dormitories
• Military personnel
• Travelers

People with immune systems that are weakened by disease or medications or not fully developed (i.e., infants) are usually affected most severely.

How is gastroenteritis diagnosed?

The doctor will take a medical history to make sure that nothing else is causing the symptoms. Also, the doctor might perform a sigmoidoscopy or radiologic examination to exclude the possibilities of inflammatory bowel disease (e.g., Crohn's disease) and pelvic abscesses (pockets of pus). A stool culture (a laboratory test to identify bacteria and other organisms from a sample of feces) can be used to determine the specific virus or germ that is causing gastroenteritis.

Other diseases that could cause diarrhea and vomiting are pneumonia, septicemia (a disease caused by toxic bacteria in the bloodstream), urinary tract infection, and meningitis (an infection that causes inflammation of the membranes of the spinal cord or brain).

Conditions that require surgery, such as appendicitis (an inflammation of the appendix), intussusception (a condition in which the intestine folds into itself, causing blockage) and Hirschsprung's disease (a condition where nerve cells in the intestinal walls do not develop properly) can also cause symptoms similar to gastroenteritis.

How is gastroenteritis treated?

The body can usually fight off the disease on its own within a few days. The most important factor when treating gastroenteritis is the replacement of fluids and electrolytes that are lost because of diarrhea and vomiting.

Foods that contain electrolytes and complex carbohydrates, such as potatoes, lean meats (for example, fish, and chicken), and whole grains can help replace nutrients. You can also buy electrolyte and fluid replacement solutions at grocery and drug stores. Or, if hospitalization is required, the nutrients can be replaced intravenously (injected directly into the veins).

Antibiotics will not be effective if the cause of gastroenteritis is a viral infection. Doctors usually do not recommend antidiarrheal medications for gastroenteritis because they tend to prolong infection, especially in children.

How can gastroenteritis be prevented?

There are several steps that you can take to reduce your risk of getting gastroenteritis, including:

• Washing your hands frequently, especially after going to the bathroom and when you are working with food.
• Cleaning and disinfecting kitchen surfaces, especially when working with raw meat or eggs.
• Keeping raw meat, eggs, and poultry away from foods that are eaten raw.
• Drinking bottled water and avoiding ice cubes when traveling, especially in developing countries.