Enteritis

Enteritis
Severe diffuse enteritis of the duodenum.
Specialty	Gastroenterology
Symptoms	Abdominal pain, diarrhea, vomiting[1]
Complications	Dehydration[2]

Enteritis is inflammation of the small intestine.^[3] Symptoms may include abdominal pain, diarrhea, and vomiting.^[1] Occasionally bloody stool or a fever may be present.^[4] Complications may include dehydration.^[2]

The most common cause is food that contains bacteria or viruses (food poisoning).^[1][2] Other causes may include medications including antibiotics, NSAIDs, and chemotherapy, radiation therapy, autoimmune conditions including Crohn's disease and celiac disease, lymphoma, portal hypertension, ischemia, and vasculitis.^[2][3][4] Initially testing is not required; however, if it persists stool culture, endoscopy, or CT scan may be performed.^[2] Subtypes include duodenitis, jejunitis, and ileitis depending on the specific part of the small intestine affected.^[5][6] When the stomach is also inflamed, it is referred to as gastroenteritis.^[3]

Treatment depends on the cause.^[4] Often no specific treatment is required.^[2] Fluids, electrolytes, and antidiarrheals may be used.^[2] Oral rehydration solution is often recommended.^[4] Generally most cases resolve within a few days.^[2]

Signs and symptoms[edit | edit source]

Symptoms may include abdominal pain, cramping, diarrhea, dehydration, fever, nausea, vomiting and weight loss.

Causes[edit | edit source]

Infectious[edit | edit source]

In Germany, 90% of cases of infectious enteritis are caused by four pathogens, Norovirus, Rotavirus, Campylobacter and Salmonella.^[7] Other common causes of infectious enteritis include bacteria such as Shigella and E. coli, as well as viruses such as adenovirus, astrovirus and calicivirus. Other less common pathogens include Bacillus cereus, Clostridium perfringens, Clostridium difficile and Staphylococcus aureus.^[8]

Campylobacter jejuni is one of the most common sources of infectious enteritis, and the most common bacterial pathogen found in 2 year old and smaller children with diarrhoea.^[9] It has been linked to consumption of contaminated water and food, most commonly poultry and milk.^[10][11] The disease tends to be less severe in developing countries, due to the constant exposure which people have with the antigen in the environment, leading to early development of antibodies.^[9]

Rotavirus is responsible for infecting 140 million people and causing 1 million deaths each year, mostly in children younger than 5 years.^[12][13] This makes it the most common cause of severe childhood diarrhoea and diarrhea-related deaths in the world.^[12] It selectively targets mature enterocytes in the small intestine, causing malabsorption, as well as inducing secretion of water. It has also been observed to cause villus ischemia, and increase intestinal motility.^[13] The net result of these changes is induced diarrhoea.

Enteritis necroticans is an often fatal illness, caused by β-toxin of Clostridium perfringens.^[14] This causes inflammation and segments of necrosis throughout the gastrointestinal tract. It is most common in developing countries, however has also been documented in post-World War II Germany.^[14] Risk factors for enteritis necroticans include decreased trypsin activity, which prevent intestinal degradation of the toxin, and reduced intestinal motility, which increases likelihood of toxin accumulation.^{[citation needed]}

Autoimmune[edit | edit source]

Crohn's disease – also known as regional enteritis, it can occur along any surface of the gastrointestinal tract. In 40% of cases, it is limited to the small intestine.^[12]

Coeliac disease – caused by an autoimmune reaction to gluten by genetically predisposed individuals.^[12]

Eosinophilic enteropathy – a condition where eosinophils build up in the gastrointestinal tract and blood vessels, leading to polyp formation, necrosis, inflammation and ulcers.^[15] It is most commonly seen in patients with a history of atopy, however is overall relatively uncommon.^[16]

Vascular[edit | edit source]

Ischemic enteritis is uncommon compared to ischemic colitis due to the highly vascularised nature of the small intestine,^[17] allowing for sufficient blood flow in most situations. It develops due to circulatory shock of mesenteric vessels in the absence of major vessel occlusion, often associated with an underlying condition such as hypertension, arrhythmia or diabetes.^[17] Thus it has been considered to be associated with atherosclerosis.^[18] Surgical treatment is usually required due to the likelihood of stenosis or complete occlusion of the small intestine.^[17] Ischemic damage can range from mucosal infarction, which is limited only to the mucosa; mural infarction of the mucosa and underlying submucosa; to transmural infarction of the full thickness of the gastrointestinal wall. Mucosal and mural infarcts in and of themselves may not be fatal, however may progress further to a transmural infarct.^[12] This has the potential for perforation of the wall, leading to peritonitis.^{[citation needed]}

Radiation[edit | edit source]

Inflammation of the gastrointestinal tract is common after treatment with radiation therapy to the abdomen or pelvis.^[19] It is classified as early if it manifests within the first 3 months, and delayed if it manifests 3 months after treatment. Early radiation enteritis is caused by cell death of the crypt epithelium and subsequent mucosal inflammation, however usually subsides after the course of radiation therapy is completed. Delayed radiation enteritis is a chronic disease which has a complex pathogenesis involving changes in the majority of the intestinal wall.^[19][20]

Diagnosis[edit | edit source]

Condition	Organ
Gastritis	stomach
Gastroenteritis	stomach and small intestine
Colitis	large intestine
Enterocolitis	large and small intestine

Diagnosis may be simple in cases where the patient's signs and symptoms are idiopathic to a specific cause. However, this is generally not the case, considering that many pathogens which cause enteritis may exhibit similar symptoms, especially early in the disease. In particular, campylobacter, shigella, salmonella and many other bacteria induce acute self-limited colitis, an inflammation of the lining of the colon which appears similar under the microscope.^[12]

A medical history, physical examination and tests such as blood counts, stool cultures, CT scans, MRIs, PCRs, colonoscopies and upper endoscopies may be used in order to perform a differential diagnosis.^{[16][8][14][21]} A biopsy may be required to obtain a sample for histopathology.

Treatment[edit | edit source]

Mild cases usually do not require treatment and will go away after a few days in healthy people.^[12][8] In cases where symptoms persist or when it is more severe, specific treatments based on the initial cause may be required.^{[citation needed]}

In cases where diarrhea is present, replenishing fluids lost is recommended, and in cases with prolonged or severe diarrhoea which persists, intravenous rehydration therapy or antibiotics may be required.^[22] A simple oral rehydration therapy (ORS) can be made by dissolving one teaspoon of salt, eight teaspoons of sugar and the juice of an orange into one litre of clean water.^[23] Studies have shown the efficacy of antibiotics in reducing the duration of the symptoms of infectious enteritis of bacterial origin, however antibiotic treatments are usually not required due to the self-limiting duration of infectious enteritis.^[8]

Word orgin[edit | edit source]

The word enteritis (/ˌɛntəˈraɪtɪs/) uses combining forms of entero- and -itis, both New Latin from Greek, respectively from ἑντερον (enteron, small intestine) and -ιτις (-itis, inflammation).^{[citation needed]}

See also[edit | edit source]

• Enteropathy
• Staphylococcal enteritis

References[edit | edit source]

External links[edit | edit source]

Classification	ICD-10: A02-A09, K50-K55 ICD-9-CM: 005, 008, 009, 555-558 MeSH: D004751
External resources	MedlinePlus: 001149