The viruses which cause gastroenteritis are rotavirus, norovirus, adenovirus, saporvirus and astrovirus. Rotavirus is the most common virus implicated in this illness. It causes endemic gastroenteritis in infants and children. Norovirus (Norwalk virus) causes ninety percent of outbreaks of gastroenteritis in the U.S. Although "the stomach flu" implies the influenza virus is associated with this infection, it is not.
Viral gastroenteritis is characterized by intense muscle aches, cramps and chills which precede nausea, abdominal pain, vomiting and/or diarrhea. Vomiting and diarrhea usually temporarily relieve the nausea and pain. The vomit and diarrhea are usually non-bloody and the stool may lighten in color. People often feel fatigued and dehydrated because of the energy involved with clearing the infection from the body and losing fluid via vomiting and diarrhea. The symptoms begin 1-2 days after becoming infected with the virus and last 1-10 days, depending on which virus is involved.
The treatment of viral gastroenteritis includes rest, analgesics and re-hydration. Tylenol may be used to treat fever and muscle cramps. The replenishment of fluids with water, electrolyte drinks or oral rehydration solutions (sugar and electrolytes) is essential to prevent dehydration. When replacing fluids, it is important to replace volume and electrolytes such as sodium, chloride, hydrogen and potassium. Water as hydration helps replace volume, but if too much is given without replacement of electrolytes, the relative concentration of these important ions decreases and metabolic/electrolyte imbalances occur in the body. Re-hydration should occur with electrolyte drinks to protect against hyponatremia. Most quality sports drinks will fill this requirement.
One should drink enough fluid to keep their mouth moist and their urine light yellow to clear. As the diarrhea and/or vomiting subsides, one may slowly introduce soft foods into the diet. Soft foods are jello, saltine crackers, pudding, rice, bread and soups without meats. It is important to watch for abdominal cramping, retching or liquid stools while trying to resume a normal diet, these symptoms could indicate the intestines are still inflamed from the infection and need more time to heal.
Adequate hydration is especially important in people who are young (infants), elderly, frail and immunocompromised their bodies are already stressed and gastroenteritis can take a huge toll on the body. These people are usually either dependent on others for fluid and food or have difficulty maintaining healthy nutrition. Vomiting and diarrhea may further deplete their bodies of already limited water and energy stores.
If dehydration occurs, the body's normal fluid balance is disturbed and potentially serious electrolyte (sodium, potassium, hydrogen, bicarbonate, and chloride) abnormalities can occur. When electrolyte abnormalities are severe and prolonged, the function of the nervous, cardiovascular, pulmonary and renal systems is compromised. Dehydration is characterized by fatigue, dry mouth, decreased urination, loose skin and lightheadedness (especially when changing from the laying to standing positions).
Although one may be tempted to use anti-diarrheal (Imodium) and anti-vomiting (Phenergan) medications, these types of medications are not recommended during this illness. Vomiting and diarrhea are the body's way of getting rid of the virus, and even though these symptoms are distressing and uncomfortable, it is important to allow the body's natural defense mechanism to function. The exception to this rule occurs when someone cannot hold down fluids and is dehydrated; the use of an anti-diarrheal medication can help the body restore its fluid balance.
Viral gastroenteritis can be prevented by thorough hand washing after eating and using the bathroom and wiping surfaces that have come in contact with infected food with disinfectant cleaners. Eating a balanced diet and taking supplements which boost the immune system can also prevent one from getting viral gastroenteritis.