What Is Gastroenteritis?

Whether it was during an international vacation-gone-wrong or after touring day care places for your tot, if you've ever had gastroenteritis -- aka the stomach flu -- you probably remember it clearly, but wish you didn't. "Most of the time, the worst part of norovirus [a common cause of gastroenteritis] is the front end, and that's because of vomiting," explains Dr. Matthew Zahn, a pediatric infectious disease specialist at Children's Hospital of Orange County in California. As the vomiting eases, the diarrhea can pick up and, all along, people with gastroenteritis may experience pain and fever, too. In other words, the condition is no fun.

But there's better news: The stomach flu usually passes quickly, doesn't require seeing a doctor and leaves its victims without any long-term damage. Read on to get more of your questions answered about this uncomfortable condition.

What Is Gastroenteritis Exactly?

The word "gastroenteritis" means inflammation of the gastrointestinal tract, explains Dr. Ari Grinspan, an assistant professor of medicine and gastroenterology at the Mount Sinai Icahn School of Medicine in New York City. So in fact, calling it the stomach flu is a misnomer, since it actually affects the intestines (not the stomach) and isn't usually caused by influenza, which is a respiratory illness, he explains.

"When we say stomach flu, we're really talking traditionally about a virus or bacteria that has taken hold briefly in your GI tract and causes gastrointestinal symptoms like nausea and vomiting," says Grinspan, who is also a gastroenterologist at The Susan and Leonard Feinstein Inflammatory Bowel Disease Clinical Center at Mount Sinai. Gastroenteritis isn't caused by one particular virus or bacteria, but rather describes the symptoms that result when any number of germs enter -- and wreak havoc on -- the digestive system. Some common culprits triggering gastroenteritis include:

Viruses

Most cases of gastroenteritis are caused by a virus. In fact, viral gastroenteritis is the second most common illness in the U.S., according the ICD 10, a medical coding system.

-- Norovirus: There are about 20 million cases of norovirus infection in the U.S. each year, says Zahn, a member of the Infectious Disease Society of America. "People think of it quite famously as 'the cruise ship illness,'" he says, though there are commonly outbreaks in all kinds of environments. The key indicator of noro, which is spread through contaminated food or water or contact with an infected person, is severe vomiting for about 24 hours 12 to 48 hours after exposure, Zahn says.

-- Rotavirus: This virus is most common in babies and kids, and manifests similarly to all types of gastroenteritis: with vomiting, diarrhea, fever, abdominal pain or all of the above, according to the Centers for Disease Control and Prevention. Passed via infected stool, hand-washing and vaccination are keys in lessening your -- and your kids' -- risk of infection.

[See: Do You Really Need to Cover the Toilet Seat With Paper?]

Bacteria

-- E. coli: You travel to a foreign country, eat local food and wind up with "traveler's diarrhea" for a day or two. Often, that's caused by E. coli, which can be transmitted when the people preparing the food don't follow best hygiene practices, Grinspan says. Fortunately, he adds, "it's almost always self-limited -- you don't need to do anything [to treat it]."

-- Salmonella: This bacteria is another common culprit leading to gastroenteritis, and is usually transmitted through food, according to the CDC. If you're infected with it after eating, you may better know the experience with gastroenteritis as foodborne illness and food poisoning. Here too, salmonella typically causes diarrhea, fever and cramps, lasts several days and clears up without treatment.

[See: Should I Wash the Turkey Before Cooking It?]

How Can Gastroenteritis Be Prevented?

The truth is, the condition can't always be avoided, but you can significantly lower your risk of succumbing to it if you take these precautions:

-- Practice excellent hand-washing hygiene. That means frequently and thoroughly washing your hands with warm, soapy water -- especially after you've gone to the bathroom, handled food or cared for someone who's infected, experts say.

-- Use caution while traveling internationally. Contrary to popular belief, the travelers most at risk for food poisoning or traveler's diarrhea while abroad aren't those on cruises or in resorts -- they're those visiting their friends and family, Grinspan says. "They're the ones going to the local place and eating the local food," he says. "People who visit friends and family also tend to be younger and more adventurous." So instead of throwing caution to the wind, follow this rule of thumb when choosing what food to eat: If you can't peel it, cook it or boil it, Grinspan says, "forget it."

-- Use common sense. Just because your neighborhood grocery store is local doesn't mean it's immune to breakouts that could cause gastroenteritis. The best way to prevent choosing an infected variety of lettuce or brand of yogurt is to simply keep your eyes and ears peeled for news of food recalls, Grinspan says. Be smart about your meals out, too, he adds: Restaurants are graded on their hygiene and food safety practices; look at those grades and dine accordingly.

-- Keep infected kids home. If your own kid already seems to have the stomach flu, help prevent its spread by keeping him or her home from day care or school for a few days, Zahn advises. While doing so can strain the family, he adds, "keeping them home does everybody a bit of good."

[See: 10 Ways to Get Over Food Poisoning.]

How Can You Treat Gastroenteritis?

Too late to prevent gastroenteritis? For most people, the best things to do are wait and rehydrate since the potential complications of the condition are almost always a result of severe dehydration, says Zahn, who recommends using an over-the-counter oral rehydration therapy to cover your hydration bases. That said, there are some people and some situations that warrant professional intervention. Among them:

-- You're immunocompromised. Older people, babies and kids, folks on medications that suppress the immune system like steroids or chemotherapy and those with weaker digestive tracts like people with inflammatory bowel disease may need antibiotics to support their immune system's ability to fight off the bug, Grinspan says.

-- You can't hold down any food or water. If everything you try to eat or drink quickly turns to vomit or diarrhea for more than 24 hours, seek treatment to prevent dehydration.

-- You're already severely dehydrated. Excessive thirst, dry mouth, dark or little to no urine, serious weakness, dizziness or lightheadedness -- all these symptoms are signs of dehydration you may not be able to correct on your own.

-- The symptoms last longer than a few days. Gastroenteritis typically clears up on its own in one to three days. If you're still debilitated after that, get help.

-- You experience bleeding. Blood in your vomit or bowel movements can signal more serious damage to your digestive tract, and shouldn't be ignored.

-- You have a persistent high fever. If a 102-degree fever or higher persists, see a doctor. "If you have severe symptoms," Zahn says, "you shouldn't just assume it's something benign."