Enteritis

Enteritis is inflammation of the small intestine that can cause diarrhea, abdominal pain, and fever. While most cases clear up on their own within a few days, understanding the different types and causes can help you know when to seek medical attention.

Table of contents

• What is enteritis?
• Symptoms and warning signs
• Causes and types
• Complications
• Diagnosis
• Treatment
• Prevention

What is enteritis?

Enteritis is inflammation of your small intestine^[1]. The small intestine is the part of your digestive system where most of the digestion and absorption of nutrients happens. When this organ becomes inflamed, it affects how your body processes food and can lead to uncomfortable symptoms.

The inflammation typically affects the inner lining of the small intestine, called the mucosa (the protective layer that lines the intestine from the inside)^[4]. When this lining becomes irritated and swollen, it causes changes in how your intestines work, leading to digestive problems.

Enteritis can occur alone, but it often happens together with inflammation in other parts of your digestive system. When it affects both your stomach and small intestine, it’s called gastroenteritis^[1]. When inflammation involves both the small intestine and large intestine (colon), it’s called enterocolitis^[4].

Most cases of enteritis are acute, meaning they come on suddenly and last only a few days^[2]. However, in some situations, enteritis can become chronic, lasting for weeks, months, or even longer^[5].

• Small intestine
• Stomach (when gastroenteritis occurs)
• Large intestine (when enterocolitis occurs)

Symptoms and warning signs

The symptoms of enteritis can begin anywhere from a few hours to a few days after you become infected or exposed to whatever is causing the inflammation^[3]. The specific symptoms you experience may vary depending on what’s causing your enteritis and how severe it is.

Common symptoms include abdominal pain and cramping, especially in the upper part of your belly and around your navel^[5]. You may experience frequent loose stools or watery diarrhea, which can sometimes be severe^[1]. The diarrhea may contain undigested pieces of food, and in some cases, you might see greenish material or even blood in your stool^[5].

Nausea and repeated vomiting are common, along with a loss of appetite^[2]. Many people also experience bloating and flatulence (gas). You may hear frequent rumbling sounds in your stomach^[5]. Fever can occur, particularly in cases of infectious enteritis, sometimes reaching 39 degrees Celsius (about 102 degrees Fahrenheit) or higher^[5].

When enteritis becomes chronic, symptoms are often related to problems with digestion and absorption of nutrients. These can include unstable bowel movements that tend toward diarrhea, weight loss and becoming thin, brittle hair and nails, and signs of vitamin deficiency (a condition where your body doesn’t have enough vitamins) such as anemia, sores in the corners of your mouth, and dry skin^[5]. Some people with chronic enteritis may develop an intolerance to milk^[5].

You should contact a healthcare provider if diarrhea doesn’t go away in 3 to 4 days, you become dehydrated, you have a fever over 38.3°C (101°F), you see blood in your stool, or you have severe belly pain^[15]. For infants and children, it’s especially important to watch for signs of dehydration (dangerous loss of body fluids), which include dry mouth, urinating less than normal or no wet diapers for 3 hours or more, no tears when crying, and changes in mental state such as irritability or lack of energy^[6].

Causes and types

Enteritis can be caused by many different factors. Healthcare providers have identified several main categories based on what triggers the inflammation.

Infectious enteritis

Infectious enteritis is the most common type and is caused by viruses, bacteria, or parasites^[9]. These germs are highly contagious and spread through contaminated food or water, or through contact with an infected person.

Viruses that commonly cause enteritis include norovirus, rotavirus, adenovirus, and astrovirus^[9]. Viral gastroenteritis is sometimes called the “stomach flu,” though it’s not actually caused by influenza viruses^[6]. In Germany, 90% of cases of infectious enteritis are caused by four main pathogens: Norovirus, Rotavirus, Campylobacter, and Salmonella^[1].

Bacteria that frequently cause enteritis include Salmonella, Shigella, Escherichia coli (E. coli), Campylobacter jejuni, Staphylococcus aureus, Clostridioides difficile (C. difficile), and Bacillus species^[2]. Campylobacter jejuni is one of the most common sources of infectious enteritis and the most common bacterial pathogen found in children two years old and younger with diarrhea^[1]. It has been linked to eating contaminated water and food, most commonly poultry and milk^[1].

Parasites such as Giardia, Cryptosporidium, and Cyclospora can also cause enteritis^[9].

Food poisoning is a common form of bacterial enteritis. You can get it after eating food or drinking water contaminated with bacteria^[2]. The bacteria can enter the food supply through improper food handling, poor hygiene, or during poultry and meat processing^[3]. Foods most often associated with food poisoning include raw poultry and meat, unpasteurized milk, raw shellfish, and fresh produce^[3].

Autoimmune and inflammatory enteritis

Some forms of enteritis are caused by autoimmune diseases, where your immune system mistakenly attacks your own body^[9]. Celiac disease is caused by an autoimmune reaction to gluten in genetically predisposed individuals^[1]. Crohn’s disease, also known as regional enteritis, can occur anywhere along the digestive tract, but the most common location is in the terminal ileum, which is the final segment of the small intestine^[1]. In 40% of cases, Crohn’s disease is limited to the small intestine^[1].

Other autoimmune causes include eosinophilic enteritis, a rare condition where certain white blood cells called eosinophils build up in the gastrointestinal tract and blood vessels, leading to polyp formation, tissue death, inflammation, and ulcers^[1].

Overuse of certain drugs can also inflame your intestines. These include nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen, certain antibiotics, alcohol, and cocaine^[9].

Radiation enteritis

Radiation enteritis occurs as a result of radiation therapy used to treat cancer^[7]. Radiation works by killing rapidly dividing cells, which destroys cancer cells but can also kill healthy cells in the protective lining of your mouth, stomach, and intestines^[2]. This leads to irritation and inflammation.

For most people, radiation enteritis is temporary and usually goes away several weeks after treatment ends^[7]. However, for some people, it may continue for months or years after radiation therapy, or it may develop long after treatment has ended^[7]. Chronic radiation enteritis can cause serious complications such as anemia, ongoing diarrhea, or bowel obstruction^[7].

Ischemic enteritis

Ischemic enteritis occurs when the blood supply to a portion of your intestines is blocked^[9]. This is an uncommon but potentially serious condition that can result in enteritis with all its typical symptoms.

Complications

The biggest risk with enteritis is dehydration caused by diarrhea and vomiting, especially when you can’t keep fluids down^[9]. Dehydration occurs when your body loses too much fluid and can lead to kidney and urinary problems as well as heart problems^[3].

Dehydration is particularly dangerous for certain groups of people. Infants and young children, older adults, pregnant women, and people with weakened immune systems or other serious health conditions are at higher risk^[6].

Symptoms of dehydration include excessive thirst, urinating less frequently or in lower amounts, dark-colored urine, fatigue, weakness, lethargy, dizziness, sunken eyes, lack of tears, and dry mouth^[3]. Infrequent passage of dark urine is a sign of dehydration, and you should be urinating at regular intervals with light and clear urine^[19].

In babies, diarrhea can cause severe dehydration very quickly^[15]. Other possible complications include long-term diarrhea that persists even after the initial infection has cleared^[15].

If enteritis lasts a long time, particularly in chronic cases, it can lead to more serious problems. These may include tissue changes that could increase cancer risk, small intestine bacterial overgrowth, and eating disorders^[1]. However, these serious complications are rare^[9].

Diagnosis

To diagnose enteritis, your healthcare provider will start by asking about your symptoms and recent exposures^[15]. They will want to know if you’ve recently eaten at a restaurant or social function where food might have been left at room temperature for long periods, if you’ve had recent travel, if you’ve been exposed to unclean water, or if anyone in your household has recently had stomach flu^[15].

Your provider will perform a physical examination to check for signs of dehydration and abdominal tenderness^[15].

Several tests may be used to identify what’s causing your enteritis. A stool culture or multiplex PCR test can look for the specific type of infection, though this test may not always identify the bacteria or other organisms causing the illness^[15]. Blood tests may be done to check for signs of infection or dehydration.

If symptoms persist or are severe, imaging tests such as a CT scan or MRI may be ordered^[15]. In some cases, your provider may recommend a colonoscopy or upper endoscopy to look at the small intestine directly and to take tissue samples if needed^[15]. These procedures involve inserting a flexible tube with a camera into your digestive tract.

For certain autoimmune forms of enteritis, specific blood tests or biopsies may be necessary to confirm the diagnosis.

Treatment

Mild cases of enteritis often don’t need testing or specific treatment^[15]. Most people with viral enteritis get better on their own with rest and plenty of fluids within a few days^[2].

The main goal of treatment is to prevent dehydration and replace lost fluids and electrolytes. You should sip liquids slowly rather than drinking large amounts at once, as drinking fluids too quickly can make nausea and vomiting worse^[19]. Take small sips often over a couple of hours. Sports drinks or oral rehydration solutions that contain electrolytes are particularly helpful^[19].

For children, oral rehydration solutions such as Pedialyte are recommended^[19]. Don’t use only water or only apple juice for children with enteritis.

If you can’t keep fluids down or show signs of severe dehydration, you may need medical care and fluids given through a vein (intravenous fluids)^[15]. This is often the case with young children.

When you start feeling better, ease back into eating slowly. Begin with small amounts of bland, easy-to-digest foods such as soda crackers, toast, gelatin, bananas, applesauce, rice, and chicken^[19]. Stop eating if your nausea returns. Avoid milk and dairy products, caffeine, alcohol, nicotine, and fatty or highly seasoned foods for a few days^[19].

Antidiarrheal medicines are sometimes used, but should be taken only under a healthcare provider’s guidance^[15]. In some cases, these medicines can actually make things worse.

If you take diuretics (water pills) or an ACE inhibitor and develop diarrhea, you may need to temporarily stop taking these medicines. However, never stop taking any medicine without first talking to your healthcare provider^[15].

Antibiotics may be needed for bacterial enteritis, but they’re not helpful for viral infections^[15]. In fact, using antibiotics carelessly for viral enteritis can lead to the condition becoming chronic^[5]. For specific bacterial infections, your provider will prescribe the appropriate antibiotic based on which bacteria is causing your illness.

People with Crohn’s disease often need to take anti-inflammatory medicines, though not NSAIDs, which can make enteritis worse^[15]. Your provider may also suggest taking a probiotic, as studies suggest some probiotics may help shorten the duration of diarrhea^[6].

Symptoms most often go away without specific treatment in a few days in otherwise healthy people^[15].

Prevention

Many cases of enteritis can be prevented by following good hygiene and food safety practices.

The most important prevention step is washing your hands thoroughly. Always wash your hands after using the toilet and before eating or preparing food or drinks^[15]. You can also clean your hands with an alcohol-based hand sanitizer containing at least 60% alcohol^[15].

When handling food, use only clean utensils for eating or handling foods, particularly when handling eggs and poultry^[15]. Cook food thoroughly, especially meat, poultry, and eggs. Use coolers to store food that needs to stay chilled and don’t leave food at room temperature for extended periods^[15].

If you’re unsure about water safety, boil water that comes from unknown sources, such as streams and outdoor wells, before drinking it^[15].

Vaccines are available for some causes of enteritis, including rotavirus vaccines for infants^[6].

If you’re caring for someone with enteritis, be especially careful about hygiene. Health care professionals and child care workers have an especially high risk of viral gastroenteritis, particularly if they don’t wash their hands thoroughly after dealing with soiled diapers, bedpans, or bathroom fixtures^[1].

Gastroenteritis cannot always be prevented, but proper hand washing, cleaning surfaces that may be infected with germs, and safe food preparation can significantly reduce your risk^[6].