Hypereosinophilic gastrointestinal disorders are immune-mediated conditions caused by increased accumulations of eosinophils in the gastrointestinal tract
Eosinophils are white blood cells released during the allergic inflammatory response and during parasitic infections. When excessive amounts of eosinophils are present, the toxic granular proteins that they release can cause damage and disease. Disorders associated with increased levels of eosinophils are known as hypereosinophilic disorders. Hypereosinophilc disorders may be autoimmune conditions; alternately, they may develop in people with autoimmune disorders and in some cases they may be confused with autoimmune diseases.
Hypereosinophilic disorders include a number of immune-mediated gastrointestinal conditions associated with increased levels of eosinophils in the gastrointestinal tract. Normally, the gastrointestinal tract, excluding the esophagus, has 200 times more eosinophils than levels present in the bloodstream. However, in the hypereosinophilic conditions, eosinophil levels are greatly increased and are also present in the esophagus.
Hypereosinophilic conditions include: immunoglobulin (IgE)-mediated food allergy, eosinophilic esophagitis (inflammation of the esophagus), inflammatory bowel disease, allergic colitis, gastro-esophageal reflux, and eosinophilic gastrointestinal disease (EGID), which is also known as eosinophilic gastroenteritis.
Pathology in the Eosinophilic Gastrointestinal Diseases
Eosinophilic inflammatory disorders are inflammatory disorders that affect the lining of all or a portion of the gastrointestinal tract. The white blood cells lining the gastrointestinal tract in these disorders are primarily eosinophils. Eosinophilic gastrointestinal disorders are diagnosed by biopsy, which shows the presence of increased gastrointestinal eosinophils.
Symptoms of Eosinophilic Gastrointestinal Disease
Eosinophilic gastrointestinal disease is often confused with other gastrointestinal disorders, including irritable bowel syndrome because the symptoms in all of these gastrointestinal disorders are non-specific. Symptoms include difficulty swallowing, nausea, pain, vomiting, diarrhea, bleeding, and constipation. In addition, this condition is often (but not always) accompanied by allergies to various foods. Increased levels of eosinophils in the blood (eosinophilia) may also be noted in patients with EGID.
Symptoms depend on the intensity and location of the inflammation in the gastrointestinal tract. For instance, difficulty swallowing is associated with involvement of the esophagus.
Eosinophilic Esophagitis
Eosinophilic esophagitis occurs when the esophagus is the only area of the inflammatory tract affected by eosinophil gastrointestinal disease. Eosinophilic esophagitis is usually caused by exposure to airborne allergens.
Relationship to other Conditions
There is a strong association between EGID and other atopic or allergic hypersensitivity-mediated diseases. For example, in one study, over half of the patients had rhinoconjunctivitis; over one third had wheezing; and nearly three fourths had a family history of atopic disease. Also of interest is the fact that nearly 10% of those with EGID had a family member who required esophageal dilatation. Initial genetic studies have shown that EGID is a polygenic disease with multiple influences on inheritance.
Treatment
Treatment for the hypereosinophilic gastrointestinal disorders consists of prednisone or other immunosuppressants to reduce inflammation and an elimination or elemental diet designed to eliminate esxposure to food allergens.
Resources:
Mark T. O'Hollaren, The Hypereosinophilic Syndromes, Medscape, 2005.
Philip Putnam, What is the Difference Between IBD, IBS and EGID? EO Solutions, Newsletter of the American partnership for Eosinophilic Disorders (APFED), Volt VI, Issue 21, Summer 2007.
