Terminal ileitis is inflammation of the terminal segment of the small intestine called the ileum. It is considered acute if it has been progressing for less than 7 days. The causes of ileitis are diverse. They include infectious, inflammatory, tumoral, medicinal or even vascular origins. The infectious origin is the most frequent. The typical symptoms of acute ileitis may be partly reminiscent of an attack of appendicitis. Many acute ileitis heal spontaneously. The treatment, which varies widely, depends on the disease in question.

Terminal ileitis is inflammation of the terminal segment of the small intestine called the ileum. An ileitis can be acute, that is to say which evolves for less than 7 days, or chronic.

The causes of ileitis are diverse.

Infectious origin

While no cause is found in nearly 33% of patients, bacterial infections are the most common causes of acute ileitis. They can affect more than 30% of patients consulting for acute ileitis.

• Yersiniose : the most frequent bacterial ileitis, it represents nearly 40% of infectious causes. Infection with Yersinia enterolitica (the most frequent) or Yersinia pseudotuberculosis occurs through the ingestion of contaminated food (raw vegetables, cold meats, dairy products);
• Salmonellosis (6,5 to 25,6%): Salmonella enteridis infections are contracted by ingesting contaminated food (undercooked chicken, unpasteurized dairy products);
• Infections Campylobacter jejuni (24,5 to 35%): Campylobacter jejuni infections are also contracted by ingesting contaminated food (undercooked chicken, unpasteurized dairy products);
• Intestinal tuberculosis : rare in Western countries, it can be present in a patient coming from a highly endemic area, an immunocompromised patient or a patient living in precarious sanitary conditions. Mycobacterium tuberculosis is the mycobacterium most often implicated, but in certain populations, especially in immunocompromised patients, Mycobacterium bovis infections by ingestion of unpasteurized dairy products may be encountered;
• Many other pathogens can give ileitis such as Clostridium difficile, Cytomegalovirus, Histoplasma capsulatum, Cryptococcosis, Actinomycosis. Anisakiasis is a cause of intestinal inflammation in consumers of raw fish.

Inflammatory origin

 Inflammatory causes include:

• Crohn’s disease, which affects nearly 12% of patients. Almost two thirds of patients with Crohn’s disease have ileal involvement;
• appendicitis and appendicular complications;
• perforation of a colonic diverticulum;
• spondyloarthropathies such as ankylosing spondylitis, reactive arthritis, psoriatic arthritis. Spondyloarthropathies are associated with inflammatory lesions preferentially in the terminal ileum in 67% of patients.

Vascular ileitis

Ileitis can also have vascular causes such as:

• acute and chronic mesenteric arterial and venous ischemia, especially in patients over 50 years of age, with a history of cardiovascular disease (heart failure, coronary artery disease, arterial occlusive disease, cardiac arrhythmias, etc.) or cardiovascular risk factors (family history, high blood pressure, smoking, diabetes);
• vasculitis: periarteritis nodosa, Churg & Strauss syndrome, Wegener’s disease, rheumatoid purpura, systemic lupus erythematosus, Behçet’s disease. This is a rare cause of ischemic ileitis.

Drug ileitis

Non-steroidal anti-inflammatory drugs (NSAIDs) are the most common drugs that cause ileitis. Other drugs can cause ileitis such as:

• oral contraceptives;
• l’ergotamine ;
• digoxin;
• diuretics;
• antihypertensive drugs.

 Various causes

9% of patients have rarer or non-digestive causes, such as:

• tumors (small bowel adenocarcinoma, lymphoma and lymphosarcoma, small bowel carcinoids, metastases);
• gynecological causes such as tuboovarian cyst or abscess, ovarian tumor, endometriosis, ovarian torsion, or ectopic pregnancy.

The typical symptoms of acute ileitis may be partly reminiscent of an attack of appendicitis. They understand :

•  abdominal pain, in the lower right part of the abdomen;
• transit disorders such as diarrhea;
• fever.

Many acute ileitis heal spontaneously. The treatment, which varies widely, depends on the disease in question.

In cases of non-severe strictly digestive infection, antibiotic treatment is not necessary, as it does not significantly reduce the duration of the disease.

In severe forms, defined by more than 6 bloody stools per day, with symptoms evolving for more than a week, high fever, immunosuppression, in an elderly patient or with significant comorbidities, antibiotic therapy should be prescribed which will reduce the duration and severity of infections. Quinolones are generally effective against the three bacteria most often responsible for acute ileitis, namely Yersinia, Salmonella and Campylobacter.