Viral gastroenteritis is one of the most common human diseases, second in incidence only to respiratory infections.
Viral gastroenteritis can be caused by several different viruses and affects people of all ages, gender, ethnicity and economic status. Its main symptoms are watery diarrhea, vomiting and cramps.
It is estimated that viral gastroenteritis is responsible for over 5 billion episodes of diarrhea each year. While the number of cases of bacterial and parasitic gastroenteritis is falling due to gradual improvement of public health and infrastructure, such as sewage system, sanitation, increased availability of drinking water and higher education of population, cases of viral gastroenteritis remains more or less stable with a much slower reduction rate.
Gastroenteritis is a term that means inflammation of the stomach and intestines. Gastroenteritis can be caused by several factors, such as infection by parasites and bacteria, drugs, alcohol, or diseases such as lactose intolerance, Crohn's disease or celiac disease. Viral gastroenteritis is any gastroenteritis caused by a virus.
When inflammation of the stomach is predominantly gastroenteritis, nausea and vomiting are prominent symptoms. When the intestines are most affected, abdominal cramps and diarrhea dominate the picture. However, it is not uncommon for patients to present a framework with extensive inflammation, suffering from vomiting and diarrhea at the same time.
Diarrhea occurs because the virus attacks the mucosal cells of the intestine, especially the ileum and jejunum, corresponding to 2/3 of the end of the small intestine. The inflammation resulting from this attack destroys the intestinal villi, which are the structures responsible for absorption of digested nutrients. In addition to preventing the absorption of nutrients, some viruses, such as rotavirus, stimulate water secretion by intestinal cells, causing a profuse watery diarrhea, making the patient evacuate more than 15 times per day.
The framework of vomiting is caused by inflammation and irritation of the stomach wall, which now barely tolerate the presence of food.
Many different viruses can cause gastroenteritis, the most common being:
Rotavirus
Norovirus (formerly Norwalk virus)
Adenovirus
Sapovirus
Astrovirus
Norovirus is the leading cause of acute diarrhea for adults, being responsible for the majority of outbreaks of viral gastroenteritis. Rotavirus is the leading cause of gastroenteritis for the pediatric population, especially for children up to 2 years. Adults also may have rotavirus diarrhea, but it is less common and usually clinically milder.
The incidence of rotavirus diarrhea in children has fallen significantly since the introduction of the vaccine against this virus. The forms of severe rotavirus gastroenteritis fell over 95% in the vaccinated population.
The viral gastroenteritis is called the "stomach flu" in English. Despite the flu virus does not cause gastroenteritis, the analogy is made due to the similarities between the modes of transmission and ease of contagion of these viruses.
In most cases the transmission is carried out by close contact with virus primarily by contaminated hands. Stool and vomit of infected patients have high virus loads. If proper hand hygiene is not performed after each evacuation, the patient can contaminate clothing and objects, facilitating the spread of the virus. Parents who do not wash their hands properly after each diapering of the child can spread the virus to the rest of the family. Food prepared by sick people (especially if raw or undercooked) or water contaminated with feces are also common pathways of transmission.
The transmission through air is also possible, mainly by saliva droplets during speech, coughing or sneezing. There are also suspicions that the virus can be transmitted through the air by vomiting. It is suggested that the cleaning of vomiting should be made not only with gloves, but also masks.
Gastroenteritis caused by norovirus, sapovirus and astrovirus may result from a mild illness with fever and mild diarrhea, to a very serious picture, with high fever and dozens of episodes of vomiting and diarrhea throughout the day. The presence of vomiting is more common with infections caused by norovirus and sapovirus, since rotavirus is usually important cause of diarrhea only for children or adults with poor immunity.
Norovirus diarrhea
The norovirus gastroenteritis usually causes symptoms 1-3 days after contamination. The picture is the following: sudden onset, vomiting and / or diarrhea. Diarrhea is often moderate with 4-8 stools per day. The stools are very liquid and there is no blood, pus or mucus. Muscle pain, malaise, headache, cramps, dyspepsia and fever around 38-39 ºC are also common. This form of gastroenteritis causes only discomfort for healthy adults but does not usually cause serious consequences. In two or three days the patient recovers from the ailment without problems.
More severe manifestations of the disease can occur in young children, elderly or debilitated patients, together with other health problems.
Rotavirus diarrhea
The rotavirus gastroenteritis is usually mild in adults but can be quite severe in very young children. Some children may have more than 20 episodes of vomiting and / or diarrhea per day, leading to severe dehydration. The rotavirus diarrhea is very watery and there are also no blood, pus or mucus. The symptoms appear usually 48 hours after infection and the patient is up to 10 days eliminating the virus in the stool. The symptoms last for 12 to 60 hours.
Most unvaccinated children will contract rotavirus by the age of 3, due to the intense and close contact between them in nurseries and kindergartens. The first infection is usually the most severe. Then, as the organism develops antibodies, lifelong reinfections usually are much milder. Therefore, rotavirus infections are usually mild in adults. 60% of properly vaccinated patients are totally immune to the virus and more than 95% are immune to severe forms of gastroenteritis.
In most cases the diagnosis is made only on the basis of medical examination. Until there are tests for rotavirus and norovirus faeces, but they are unnecessary in most cases, since the treatment of watery diarrhea with no signs of blood or pus is basically the same, whether of viral origin or not.
Stool examination may be helpful if the physician has doubts between viral or bacterial gastroenteritis. Generally, symptoms are different, but in some cases the distinction may not be as straightforward.
There is no specific remedy to cure diarrhea caused by viruses. Nor is it necessary, since in most cases the disease is self-limiting and of short duration. The main goal of treatment is to prevent the patient from dehydration because of the large water losses in stool and vomiting. Proper hydration is very important, especially for young children. In severe cases, hospitalization for observation of intravenous fluids may be necessary.
Already there are oral solutions for hydration available in pharmacies, such as Pedialyte. This popular serum is distributed free in pharmacies. This form of hydration is more efficient than pure water or oral rehydration done at home.
Antibiotics should not be used because they only work for diarrhea caused by bacteria. Medicines such as Loperamide (Imosec), should not be used in acute diarrhea of infectious origin because they can worsen and cause significant side effects.
Probiotics like lactobacillus (Floratil - Saccharomyces boulardii) can be useful in helping to reduce the length of illness in some cases. But do not expect miraculous effects, such as resolution of diarrhea within a few hours.
There is no need to stop feeding during the framework of gastroenteritis. Just avoid very fatty food as it worsens your sickness. It is good to keep to any very restrictive diet. Give preference to water-rich foods such as fruits, soups, yogurts, etc. Most patients do not present problems with the intake of dairy products.
