What You Should Know About the 24-Hour Stomach Flu

If you have ever come down with the stomach flu and have experienced bouts of crushing nausea, vomiting, and diarrhea, it is not uncommon to be consoled by someone who will assure you that it's just a "24-hour bug."

But is there really such a thing? Can a stomach bug actually slip through your system as fast as that, leaving behind only a vague memory of the illness?

When describing a stomach bug, the word "flu" is a bit of misnomer. In purely medical terms, the flu (influenza) is a common viral infection that primarily affects the respiratory system and manifests with symptoms such as fever, chills, muscle aches, cough, and congestion.

By contrast, the stomach flu is more accurately referred to as gastroenteritis. Unlike influenza, gastroenteritis can be caused by any number of disease-causing pathogens, including bacteria, viruses, parasites, and even fungi. It is commonly associated with the rotavirus in children and either the norovirus or the Campylobacter bacteria in adults. Here's a brief look at the main differences between stomach flu and seasonal flu.

Clearly, because the causes of stomach flu are varied, it may be overly optimistic to suggest that it will automatically resolve in 24 hours. It may do so, but it can also take up to 10 days for some to fully recover.

Gastroenteritis, also known as infectious diarrhea, is characterized by the inflammation of the stomach and gastrointestinal tract and can lead to vomiting, diarrhea, fever, and abdominal distress. In general stomach flu appears suddenly, hits hard, than then gets better once the symptoms subside.

While many types of viral illnesses such as influenza and the common cold tend to be transmitted in the air, gastroenteritis tends to be transmitted contaminated food and water or from person-to-person by contact. Handwashing after using the restroom and strict attention to food preparation guidelines are both aimed at preventing this transmission.

The most common causes of stomach flu include:

• Viruses such as rotavirus, norovirus, adenovirus, and astrovirus are known to cause viral gastroenteritis. These represent around 70 percent of stomach flu in children (most especially the rotavirus), while the norovirus represents 90 percent of all cases in the U.S. The viruses are extremely contagious and easily passed from person to person or indirectly through contaminated food and water.
• Bacterial causes include Campylobacter jejuni, Escherichia coli, Salmonella, Shigella, and Clostridium difficile. Bacteria-associated gastroenteritis is primarily related to something you ate. Of the possible bacterial causes, C. jejuni represents around 50 percent of all cases. Many of these infections are transmitted through contaminated poultry or other tainted foods, including meat, produce, and dairy products.
• Parasites are less common causes of gastroenteritis in the U.S but still account for around 15 percent of all cases in children. The primary culprit is Giardia lamblia which is spread through contaminated food, water or by the fecal-oral route (poor hygiene).

Symptoms of gastroenteritis are usually acute and resolve on their own without the need for medical intervention. The main focus of treatment is the prevention of dehydration due to the severe loss of fluids. Supportive therapies may include:

• Rehydration with water or electrolyte-rich sports drinks (although sodas and any fruit juice high in simple sugar should be avoided)
• A BRAT diet (consisting of banana, rice, apple, and toast) to ease a queasy stomach and help bind loose tummies
• Anti-nausea medicines like Reglan (metoclopramide) to reduce the incidence of vomiting and lessen the risk of dehydration
• Tylenol (acetaminophen) to relieve fever with fewer side effects and less stomach upset

Call your doctor immediately or go to the emergency room if vomiting or diarrhea persists for more than 24 hours, if vomiting is violent (or there is blood in the vomit), if you can't keep fluids down, or if there are signs of severe dehydration (dizziness, weakness, confusion, fainting, fever over 101 F).