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What is gastroenteritis?

Gastro, infectious diarrhea, traveler's diarrhea, stomach bug, “stomach flu”. Whatever you like to call it, in medical terms, it all boils down to one thing - gastroenteritis - which literally means an inflammation (itis) of your stomach (gastro) and intestines (entero) that typically makes its presence known in the form of vomiting and/or diarrhea. It is usually caused by a virus or bacteria that gains access to your gut via your mouth. Gastroenteritis can affect anyone, anywhere, and is a very common cause of illness worldwide.

A healthy digestive system, but sometimes things go wrong

Your digestive system has the job of breaking down the food you eat into nutrients that can be absorbed by the bloodstream and delivered to cells and tissues throughout your entire body, where they are used for energy, cell growth and repair. Multiple physical and chemical processes work together to make this an efficient process, controlling and coordinating everything from food intake, physical and chemical digestion, absorption of nutrients, water and electrolytes, and the processing of waste materials. For the most part, your intestinal immune system protects your digestive system from infection by harmful microbes. However, sometimes, disease causing microbes escape the immune system, causing inflammation that throws the digestive process out of balance, and results in the typical signs and symptoms of gastroenteritis. In fact there are many different microbes that can cause gastroenteritis:
Viral gastroenteritis: rotavirus, norovirus (Norwalk virus being the only species in this group), adenovirus and astrovirus. These viruses tend to invade and replicate within the epithelial layer of the gut wall causing patches of damage that interferes with absorption, and causes the intestines to secrete water, whereas usually one of their main functions is to absorb water.
Bacterial gastroenteritis: Campylobacter species, Escherichia coli, Salmonella, Shigella, Clostridium difficile, and Vibrio cholerae, which causes cholera. Bacteria adhere to the intestinal wall, multiply, and then further invade the gut lining, particularly in the colon. In addition to producing toxins that alter the absorption of water and electrolytes, bacterial infections of this sort often cause intestinal ulceration and bleeding.
Parasitic gastroenteritis: various unicellular organisms, called protozoans, including Giardia lamblia, Entamoeba histolytica, and Cryptosporidium species. These microbes adhere to the intestinal walls causing microabscesses, ulcers, bleeding, and inflammation.
It’s not only infections that inflame the digestive tract, as some non-infectious conditions may also do this. For example, some medications, such as non-steroidal anti-inflammatories that are commonly used to treat pain caused by inflammatory diseases like arthritis, as well as certain foods; for example, gluten. Long-term, or over use of nonsteroidal anti-inflammatories may damage the digestive tract by interfering with mucus secretion, causing ulcers and bleeding. In contrast, for some people, gluten triggers an autoimmune reaction that destroys enterocytes, the cells in the inner lining of the intestine that are responsible for absorbing nutrients, disrupts the structure of the intestinal wall, and inflames the intestines. With continued exposure to the irritant, you are likely to experience chronic gastroenteritis with diarrhea and other symptoms lasting more than four weeks.

Symptomy

Gastroenteritis is most commonly caused by viruses, sometimes bacteria, and less often parasites. The signs and symptoms are generally similar regardless of the microbe causing the infection, and usually start within one to three days after you become infected. Diarrhea - which is when your stool becomes watery, and you need to go to the toilet frequently and urgently - is the most common symptom, and can range from mild to severe. It is not uncommon to experience one or more other symptoms, such as stomach cramps, vomiting, nausea, fever, chills, or headache. Viral infections usually get better within a week to ten days, but some bacterial infections can cause severe abdominal pain that may last several weeks.
Although often gastroenteritis presents as a sudden transient attack of diarrhea, if it persists it can lead to severe dehydration, which can become a medical emergency. Signs of dehydration include extreme thirst, not urinating throughout the course of the day or producing only a small volume of urine, dry lips and mouth, sunken cheeks, dizziness, floppiness, and loss of skin turgor (a measure of elasticity of the skin).

Causes and risk factors of gastroenteritis

Many of the risk factors that increase the likelihood you will have gastroenteritis at one time or another are related to the transmission of disease causing microbes, which spread through the oral-fecal route; ingesting water or food contaminated with feces, person-to-person contact, or direct exposure to contaminated feces. Children are particularly vulnerable to gastroenteritis because of a lack of immunity. Risk is increased in the developing world where transmission is increased due to poor hygiene, crowded living conditions, and poor nutrition. Although adults are less susceptible as a result of acquired immunity, the risk of gastroenteritis increases again as your immune system weakens with age. This means elderly people are more susceptible especially if living close together in nursing homes where infections spread easily.
Behaviors that increase the likelihood of transmission, also increase the risk of gastroenteritis. These include failing to breastfeed your baby (up to 12 months of age provides the best protection), using a baby bottle to feed your baby (these easily become contaminated as they are difficult to clean), storing cooked food at room temperature for several hours before eating it (this allows the bacteria to multiply), storing drinking water that could become contaminated before you drink it, or drinking water that is contaminated at source, not washing your hands properly after using the washroom, or before preparing or handling food, and not disposing of feces hygienically, particularly baby diapers. In addition you increase your risk of gastroenteritis, also known as “food poisoning”, by eating certain higher risk foods including raw or undercooked meat or poultry, unpasteurized milk or cheese, eggs, fruit, and vegetable juices.
Finally, like the flu virus, the microbes that cause gastroenteritis are seasonal, which means you are more vulnerable at certain times of the year than others. Places that have a wet and dry season tend to have outbreaks during the wet season, while regions with four seasons are more likely to have outbreaks in the winter.

How likely are you to get gastroenteritis?

Gastroenteritis occurs all over the world and can affect anyone of any age and any race. Worldwide, an estimated three to five billion children under the age of five experience acute viral gastroenteritis,1 and a total of around 1.5 million people (children and adults) die from this condition, annually.2
Rotavirus is the most common cause of gastroenteritis in children, while norovirus is more common in adults and accounts for the vast majority of outbreaks in developed countries. Localized epidemics occur due to the ability of some microbes, including norovirus, to spread rapidly from one person to the next when groups of people are in close quarters, such as in hospitals and nursing homes, and because it is possible to be infectious even after the diarrhea has stopped increasing the chances of spreading it to someone else. Parasitic gastroenteritis is more common in the developing world, and your chances of getting it are higher if you travel to regions where it is more prevalent. Other environments where parasites commonly flourish include daycares and disaster zones.

Can gastroenteritis be prevented?

The best way to prevent gastrointestinal disease is to take simple precautions that reduce the likelihood you will introduce disease causing microbes into your mouth. These include washing your hands thoroughly, particularly after using the toilet, and ensuring your children do too. Avoiding sharing eating utensils, and using separate personal items like toothbrushes and towels. Disinfecting hard surfaces around your home, and keeping your distance if you or a family member has an infection. It is also a good idea to wash all fruit and vegetables, and cook meat and poultry all the way through, to kill any harmful bacteria that may be lurking there.
In addition to these hands on strategies, there are currently two rotavirus vaccines approved by global health agencies. The World Health Organization has recommended all national vaccination programs offer the rotavirus vaccine to prevent infection in babies and young children. Many developed countries now offer this vaccine, but unfortunately developing countries have had more difficulty making it available, due to the lack of infrastructure and resources that are needed to offer wide spread access.

Diagnosis and treatment of gastroenteritis

Diagnosis of gastroenteritis is generally based on your symptoms, a physical exam, and knowledge of outbreaks of infectious disease in your community. However, if your symptoms are very severe, or if you are showing signs of dehydration, you may need to provide a stool sample to help rule out other possible causes of illness.
Most cases of gastroenteritis get better on their own, within a week or so. Treatment initially consists of self-care measures, such as making sure you stay hydrated, and avoiding eating or drinking anything that might upset your stomach even more; for example, spicy food, or alcohol. If your symptoms are very severe, you may need to take antidiarrheal or antiemetic medications to reduce diarrhea and vomiting. There are no specific medications for treating viral gastroenteritis; however, you may be given antibiotics if a specific causative microbe has been identified. Antibiotics are only effective against bacterial infections and are often avoided as much as possible in order to prevent the development of antibiotic resistant strains of bacteria. In very severe cases, you may need to go to hospital for intravenous fluids and nutrition, and to avoid more serious complications.

Weź pod uwagę:

  • Gastroenteritis is a major cause of disease worldwide. The CDC in America has found that from 1999 to 2007, the annual number of deaths due to gastroenteritis more than doubled from 7,000 to 17,000, and that it was mainly adults over 65 years of age who died.4 It turns out that Clostridium difficile, or C. diff, bacterium was responsible for the majority of these deaths, and that this coincided with the emergence of an antibiotic resistant strain of Clostridium difficile. As most antibiotic resistance develops because of inappropriate use of antibiotics, this demonstrates the importance of only taking antibiotics as prescribed by a healthcare provider, and always completing the prescribed course of antibiotics.
  • The rotavirus vaccine was first made available in the United States in 2006. By 2012, hospitalization rates for acute gastroenteritis in US children under five years of age had dropped by 55%, and hospitalization for gastroenteritis due to rotavirus infection itself was rare.5 Almost 75% of eligible children in the US have now been vaccinated with the rotavirus vaccine, and efforts to increase vaccine coverage are ongoing.

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