Gastric Flu (Intestinal Flu) – Causes, Symptoms, Treatment

What is the Gastric Flu?

Gastric flu is a common term used for infectious gastroenteritis, which causes small outbreaks in the workplace, schools and within the home. There are many causes of infectious gastroenteritis – a number of bacterial, viral and protozoal species may cause this inflammation of the stomach, small and large intestine.

The term gastric flu specifically is commonly used to describe viral gastroenteritis, along with other terms like intestinal flu, tummy flu and stomach flu. It is important to note that while the term ‘flu’ is used to describe gastroenteritis, it is not related to influenza except for the fact that it is sometimes spread through the airborne route.

Causes of the Gastric Flu

Viral gastroenteritis is mainly caused by the rotavirus and norovirus (Norwalk virus). The rotavirus is often transmitted by the fecal-oral route and is more often seen among children. The norovirus can be transmitted by the airborne route, just like the seasonal influenza. Droplets from sneezing and coughing may transmit the infection and accounts for outbreaks in confined areas even if the infected person does not make direct physical contact (touch, sharing cutlery and utensils) with others.

The incubation period for viral gastroeneteritis caused by the norovirus is between 12 to 48 hours and the infection can last for up to 3 days, with residual symptoms persisting for up to 2 days after this period. Patients are infectious for up to 48 hours after symptoms resolves and returning to work or school within this time can still contribute to an outbreak.

Refer to the article on Stomach Bug Causes for more information on bacterial, viral and protozoal gastroeneteritis.

Signs and Symptoms of the Gastric Flu

The word gastric refers to the stomach while intestinal refers to the intestines.  The stomach, small and large intestines are affected by this infection resulting in the typical signs and symptoms seen in gastroeneteritis. This includes :

• Nausea
• Vomiting
• Diarrhea
• Abdominal pain
• A fever is almost always present in a case of viral gastroenteritis and can be as high (104F/40C).

Other symptoms include :

• Headache
• Fatigue
• Malaise

Refer to the article on Stomach Flu Signs and Symptoms for more information on the symptomatology of gastroenteritis.

Dehydration is a complication of fluid loss from vomiting and diarrhea. Dehydration should be taken seriously and if adequate rehydration cannot be managed in the home environment, hospitalization may be necessary.

Treatment of the Gastric Flu

The symptoms usually settle within 3 to 5 days without any medical treatment. Oral rehydration is essential to minimize the extent of dehydration. Solid foods should be reintroduced to the patient as soon as vomiting ceases.

Immunocompromised patients may need special care as the infection can be ongoing and lead to serious complications or even death. If the symptoms are persisting for more than 5 days in any person, hospitalization and IV infusion may be essential.

Refer to the articles on Stomach Flu Treatment and Oral Rehydration Therapy and BRAT Diet.