What causes ileitis

What is Ileitis?

Ileitis is a medical term that describes inflammation of the ileum. The ileum is the final section of your small intestine, situated between the jejunum (the middle section of the small intestine) and the large intestine (colon). It plays a crucial role in absorbing vitamin B12, bile salts, and other nutrients that haven't been absorbed by the jejunum.

Common Causes of Ileitis

Infectious Causes

Infections are among the most frequent culprits behind ileitis, especially acute cases. These can be caused by a variety of microorganisms:

• Bacterial Infections: Bacteria such as Salmonella, Shigella, Campylobacter, and Yersinia can infect the ileum, leading to inflammation. These infections often result from consuming contaminated food or water. Symptoms can include diarrhea, abdominal pain, fever, and sometimes vomiting.
• Viral Infections: Viruses like rotavirus and norovirus can also cause inflammation of the small intestine, including the ileum, although they often affect the entire gastrointestinal tract.
• Parasitic Infections: Parasites such as Giardia lamblia (causing giardiasis) and Cryptosporidium can infest the small intestine and lead to inflammation.

Inflammatory Bowel Diseases (IBD)

Chronic inflammation of the ileum is often a hallmark of Inflammatory Bowel Diseases (IBD), with Crohn's disease being the most prominent example.

• Crohn's Disease: This is a chronic autoimmune condition that can affect any part of the digestive tract, from the mouth to the anus. However, it most commonly affects the end of the small intestine (ileum) and the beginning of the large intestine (colon). Crohn's disease causes inflammation that can extend through the entire thickness of the intestinal wall, leading to symptoms like chronic diarrhea, abdominal pain, weight loss, fatigue, and sometimes complications like strictures (narrowing) or fistulas (abnormal connections).
• Ulcerative Colitis: While primarily affecting the colon, ulcerative colitis can sometimes involve the terminal ileum in a condition known as "backwash ileitis."

Other Causes

Beyond infections and IBD, other factors can contribute to ileitis:

• Medications: Certain medications, particularly Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) like ibuprofen and naproxen, can irritate the intestinal lining and, in some individuals, lead to inflammation of the ileum. This is sometimes referred to as NSAID enteropathy.
• Radiation Therapy: Patients undergoing radiation therapy for abdominal or pelvic cancers may develop radiation enteritis, which is inflammation of the small intestine caused by radiation damage. The ileum is frequently involved due to its location.
• Ischemia: Reduced blood flow to the ileum (ischemic ileitis) can cause inflammation and damage to the intestinal tissue. This is more common in older adults with cardiovascular issues.
• Allergies and Intolerances: While less common, certain food allergies or intolerances might trigger inflammatory responses in the gut, potentially affecting the ileum.
• Foreign Bodies or Obstructions: In rare cases, a swallowed foreign object or a blockage in the ileum can cause irritation and inflammation.

Symptoms of Ileitis

The symptoms of ileitis can vary depending on the underlying cause and severity, but commonly include:

• Abdominal pain, often in the lower right side
• Diarrhea (which may be bloody)
• Nausea and vomiting
• Loss of appetite
• Weight loss
• Fever
• Fatigue

Diagnosis and Treatment

Diagnosing ileitis typically involves a combination of medical history, physical examination, blood tests, stool tests, and imaging studies (like CT scans or MRI). Endoscopic procedures such as colonoscopy or upper endoscopy with ileoscopy may also be performed to visualize the inflammation directly and obtain biopsies. Treatment depends heavily on the cause, ranging from antibiotics for infections to anti-inflammatory medications and immunosuppressants for IBD, or lifestyle adjustments for medication-induced inflammation.