Gastroenteritis (Stomach Flu)

How can you tell if you have food poisoning or a virus?

Timing of symptoms is the most important differentiating factor between foodborne and viral illnesses.

Food poisoning—or foodborne illness—can refer to a variety of different diseases, but typically describes an acute onset of nausea, vomiting, and/or diarrhea within six hours of a suspect meal. In these cases, a preformed toxin (usually by staph aureus) causes an inflammatory reaction within the gastrointestinal tract leading to symptoms.

Viral illnesses, which can also be passed through food, have a longer incubation period—typically greater than 16 hours—and are more likely to include low-grade fever.

What are the most common gastroenteritis symptoms?

Fortunately, the majority of gastroenteritis cases do not last more than a few days, and definitely no longer than two weeks. Most people will suffer from nausea, vomiting, watery diarrhea, abdominal cramping and, sometimes, a low-grade fever.

Medically, what makes you worry it could be something that needs more treatment or attention than a typical gastroenteritis?  

Symptoms become more worrisome when they include persistent or high fever (> 101 F), blood in the stool, painful bowel movements, and the inability to keep hydrated. Symptoms that don’t start to show improvement after five days are also concerning.

Do people need to have an exam or tests?

Stool analysis in patients with acute gastroenteritis can help determine if an infection is bacterial. However, since viruses cause the majority of cases of gastroenteritis, most people with symptoms lasting more than days and with no warning symptoms such those as listed above do not need additional testing.

Testing can help guide treatment in patients with a specific clinical history, such as recent ingestion of raw oysters or undercooked meats, or recent antibiotic use--all of which make a bacterial cause more likely.

Are there patients who are vulnerable to getting more serious infections or becoming more ill?

Patients who have a compromised immune system or are likely to get dehydrated rapidly require greater care. These patients include young children, people who are on immunosuppressant medications or have AIDS, and the elderly. Women who are pregnant should also take special care.