Colloquially known as the "stomach flu," gastroenteritis is the irritation and inflammation of the intestinal tract resulting from a viral, bacterial or parasitic infection. Although the stomach and small intestine are involved, the moniker 'stomach flu' is misleading in that it is entirely unrelated to traditional influenza. A disease commonly afflicting the developing world, it is estimated that over 2 billion cases of gastroenteritis occurred in 2015, resulting in 1.3 million deaths. The malady spreads easily, with just over 3 million cases in the United States annually. It is short term in nature and usually resolves within days to weeks. Gastroenteritis can take hold in all age groups, although frequency may decrease in adulthood due to increased immunity of the human host. Causative bacteria, parasites or viruses may spread through contaminated food or water, or contact with an infected person. Viruses are the most common cause of gastroenteritis. Generally, antibiotics are not required in bacterial cases. It is critical for those diagnosed with gastroenteritis to monitor their fluid intake, replenishing frequently as dehydration is a common complication associated with the ailment. The severity of infection may depend on the individual's inherent immune strength.
Because hospitals and nursing homes house a greater number of immunocompromised individuals, it may be easier for this relatively contagious malady to take hold and spread there. This is why it is critical for hospitals to maintain sanitary conditions anywhere food is prepared and served for patients.
Nosocomial outbreaks of gastroenteritis are not only a burden on hospital services but cost an estimated $150 million annually.
Causes of Gastroenteritis
Viral gastroenteritis is the most prevalent type, with rotavirus commonly affecting children and norovirus and Campylobacter affecting adults. Rotavirus appears with similar frequency in both the developed and the developing world. Children are especially susceptible to the condition due to poor hygiene skills and lack of existing immunity. Adeno virus and astrovirus are likewise common causes of gastroenteritis, with viral infections accounting for over 70% of pediatric cases. In 18% of cases, norovirus is the culprit. When localized epidemics of gastroenteritis occur, norovirus is the cause 90% of the time. Such outbreaks occur anywhere in which people are in close quarters. Hospitals, restaurants, and cruise ships have been known to see such epidemics. After the diarrhea symptom resolves, the host may remain infectious.
Viral transmission is achieved through consumption of contaminated food or water or person to person contact in confined spaces. A common route of transmission is the fecal-oral route, by which someone who has not washed their hands after using the restroom handles something that another person later eats or drinks. This is why prevention with good hygiene and hand washing is of the utmost importance. Certain shellfish including undercooked oysters can be a cause of infection as well.
Although bacterial gastroenteritis can also result from bad hygiene, there are other causes. Consuming food that has been left at room temperature for an extended period of time, was not reheated well or is undercooked may also lead to bacterial gastroenteritis. However, there are numerous other culprits. Meat or poultry may come into contact with certain bacteria during processing and handling, later causing infection in those who consume it. Failure to wash hands before handling food, unpasteurized vegetable, fruit or dairy products, untreated water from a well or steam, and using unclean utensils can all potentially cause bacterial gastroenteritis. Causative bacteria include:
- Campylobacter jejuni
- E coli
Because of the public health implications of parasitic gastroenteritis, a diagnosis should be vigorously pursued in suspected cases so as to identify and treat the patient with special considerations to their condition or to successfully rule out parasitic gastroenteritis. This should take place in the appropriate clinical setting. The parasites Giardia and Cryptosporidium are the most common cause of parasitic disease in the United States. Government-sponsored public health literature encourages examination of the patient's stool for parasites and ova on three alternate days, in order to make a confident diagnosis.
Parasitic infection of the gut is common in pediatric patients and may spread easily in day care or school settings. Patients with parasitic gastroenteritis should be kept from their school or daycare settings to prevent further transmission of the pathogen.
Traveling to endemic areas can be a potential cause of parasitic gastroenteritis and for this reason, patients who have traveled to these areas should be tested by serology and stool examination.
Symptoms of Gastroenteritis
Symptoms typically begin 12-72 hours after infection. While viral infections may resolve with one week, bacterial infections and the severe abdominal pain which accompany them may last for several weeks. There are a handful of staple symptoms associated with gastroenteritis. These include:
- abdominal pain
- Low-grade fever
- muscle aches
Characteristics of the patient's stool may be examined, as they may change in a way indicative of gastroenteritis. These include:
- Presence or absence of reducing substances
- Presence or absence of blood
- White blood cell (WBC) count
- Serum WBC count
Bloody stool is more likely indicative of bacterial gastroenteritis. The chief complication associated with gastroenteritis diarrhea is dehydration. If repeat infection occurs, long term effects may result such as stunted growth, long term cognitive delay, and malnutrition. Specific viral infections may produce benign infantile seizures.
Treatment for Gastroenteritis
Because of the self-healing nature of the malady, it does not usually require medication. Preventing dehydration is one of the chief concerns of physicians, who may administer a rehydration solution or intravenous delivery if the dehydration is especially severe. Sugary and fruity drinks are not recommended for children experiencing diarrhea as they can exacerbate it. If warranted, a nasogastric tube may be used to administer fluids to children.
Formula fed infants with gastroenteritis should resume formula after oral rehydration therapy. Breast fed infants should continue with breast feeding as usual.
Risk Factors of Gastroenteritis
Like the risk factors of gastroenteritis in the general population, the risk factors of hospital acquired infection and outbreaks are greatly associated with having a high volume of people in close proximity of one another. A greater number of beds in a given hospital unit is a hazard, according to one study. This was true of both geriatric and general medical care units. Larger care units, in general, are at a greater risk for gastroenteritis outbreaks.
Outside of hospital-acquired infection risk factors, those who are traveling may be at a higher risk for developing gastroenteritis. Schoolchildren and those who frequent confined spaces are also more susceptible.
Prevention of Gastroenteritis in Hospitals
Vaccination against rotavirus, a chief cause of gastroenteritis in children, is an available means of preventing against gastroenteritis in hospitals and the community alike. However, there are straightforward methods of prevention as well, such as hand washing prior to handling food and ensuring all food is cooked thoroughly. Fruits and vegetables should be vigorously washed. Hospital staff should discourage patients from sharing utensils in any capacity. Exceptionally good hygiene should be practiced in hospital cafeteria kitchens to reduce incidents and outbreaks.