Eosinophilic gastroenteritis: epidemiology, diagnosis and management

Gastrointestinal eosinophilia

Gastrointestinal eosinophilia, a broad term for abnormal eosinophil accumulation in the gastrointestinal tract, involves many different disease identities. These diseases include primary eosinophil associated gastrointestinal diseases, gastrointestinal eosinophilia in hypereosinophilic syndrome, and all gastrointestinal eosinophilic states associated with known causes. Each of these diseases has its unique features but there is no absolute boundary between them. All three groups of gastrointestinal eosinophila are described in this article, although the focus is on primary gastrointestinal eosinophilia.

Evaluation and differential diagnosis of marked, persistent eosinophilia

Hypereosinophilic syndromes (HES) are a group of heterogeneous disorders many of which remain ill-defined. By definition, the HES must be distinguished from other disorders with persistently elevated eosinophilia with a defined cause. Although marked eosinophilia worldwide is most commonly caused by helminth (worm) infections, the diagnostic approach must include noninfectious (nonparasitic) causes of marked eosinophilia as well.

Los granulocitos eosinófilos: de residentes habituales de la mucosa gastrointestinal normal a protagonistas agresivos de la gastroenteritis eosinofílica

Because of their biological affinity for normal gastrointestinal (GI) mucosa, eosinophilic granulocytes are "normal residents" in the mucosa. This physiological GI eosinophilia translates into a state of "permanent normal inflammation", which means that the mucosa's local immune system is constantly confronted by dietary proteins and indigenous microorganisms. This eosinophilic infiltration of the GI mucosa is increased, reactively, in the course of local inflammatory processes, collagenosis, infections (especially helminthic infections), vasculitis, neoplasms and IgE-dependent allergic reactions to food. Lastly, GI eosinophilia that is clearly aggressive, both because of its intensity and its persistence, is what characterizes eosinophilic gastroenteritis. In the present article, we summarize the ethiopathogenic and clinico-epidemiological features of this process, as well as its position within the field of immunopathologic food intolerance.

Quantity and distribution of eosinophils in the gastrointestinal tract of children

There are a lack of data on the quantity and location of eosinophils in the gastrointestinal tract of healthy individuals. Accordingly, we examined gastrointestinal biopsies obtained during endoscopic evaluation of pediatric patients. Biopsies were previously interpreted as having no diagnostic abnormality. The presence of extracellular eosinophil constituents and the quantity of eosinophils in atopic versus nonatopic individuals was determined. In the esophagus, eosinophils were present in only 2.7% of high-power fields (hpf), with a mean value of 0.03+/-0.10 eosinophils/hpf (mean+/-standard deviation) and a maximum of 1 eosinophil/hpf. Examination of the antrum and fundus revealed similar numbers of eosinophils in the lamina propria (1.9+/-1.3 and 2.1+/-2.4 eosinophils/hpf, respectively), with no eosinophils observed in the surface epithelium. In the small intestine, there were 9.6+/-5.3 (maximum, 26 eosinophils/hpf) and 12.4+/-5.4 eosinophils/hpf (maximum, 28 eosinophils/hpf) in the intercryptal lamina propria of the duodenum and ileum, respectively. The number of eosinophils in the surface epithelium and crypt epithelium was minimal. In the large intestine, the highest concentration of eosinophils was observed in the cecum (20.3+/-8.2 eosinophils/hpf; maximum, 50 eosinophils/hpf), and there were lower concentrations in the transverse and sigmoid colon (16.3+/-5.6 and 8.3+/-5.9 eosinophils/hpf, respectively). The percentage of fields demonstrating extracellular eosinophil granules in all gastrointestinal segments was 70% to 93%, and extracellular granules were most numerous at the edge of the biopsy (P<0.05). Atopic and nonatopic patients had comparable numbers of eosinophils. These data establish baseline gastrointestinal eosinophil values in pediatric patients without apparent pathological disease.

Las esofagogastroenteritis eosinofílicas dentro del espectro de las alergias alimentarias

Under normal conditions, the digestive tube immune system is capable of establishing an effective plan of tolerance to food that is eaten daily by the human beings. However, this tolerance plan sometimes fails and in the final steps of this immunological dysreaction, other cellular elements, usual residents of the digestive mucous, such as eosinophil granulocytes, generally participate, together with the main cells of this system. This is the case, among others, of the so-called EGE-Eos. The authors summarize the spectrum of pathogenic options of these immunological food intolerances that range from those in which "all" depend on a specific IgE (GI food anaphylaxis) and those others in which "nothing" depends on this reagin (celiac sprue). An intermediate position would be occupied by the EGE-Eos in which there seems to be overlapping of immune reactions of cellular character together with a certain role of the IgE. These pathogenic pathways frequently cross a tangle of cellular and molecular events that cannot be untangled with either an image or one thousand words.

Eosinophilic esophagitis: A newly established cause of dysphagia

Eosinophilic esophagitis has rapidly become a recognized entity causing dysphagia in young adults. This review summarizes the current knowledge of eosinophilic esophagitis including the epidemiology, clinical presentation, diagnostic criteria, pathophysiology, treatment, and prognosis. An extensive search of PubMed/Medline (1966-December 2005) for available English literature in humans for eosinophilic esophagitis was completed. Appropriate articles listed in the bibliographies were also attained. The estimated incidence is 43/10⁵ in children and 2.5/10⁵ in adults. Clinically, patients have a long history of intermittent solid food dysphagia or food impaction. Some have a history of atopy. Subtle endoscopic features may be easily overlooked, including a “feline” or corrugated esophagus with fine rings, a diffusely narrowed esophagus that may have proximal strictures, the presence of linear furrows, adherent white plaques, or a friable (crepe paper) mucosa, prone to tearing with minimal contact. Although no pathologic consensus has been established, a histologic diagnosis is critical. The accep-ted criteria are a dense eosinophilic infiltrate (>20/high power field) within the superficial esophageal mucosa. In contrast, the esophagitis associated with acid reflux disease can also possess eosinophils but they are fewer in number. Once the diagnosis is established, treatment options may include specific food avoidance, topical corticosteroids, systemic corticosteroids, leukotriene inhibitors, or biologic treatment. The long-term prognosis of EE is uncertain; however available data suggests a benign, albeit inconvenient, course. With increasing recognition, this entity is taking its place as an established cause of solid food dysphagia.

Gastric motor dysfunction: is eosinophilic mural gastritis a causative factor?

Delayed gastric emptying caused either by gastric motor dysfunction or by gastroparesis is a profoundly debilitating disorder. When unresponsive to medical therapy, patients may undergo radical surgery including near-total gastro-oesophageal, with varied symptomatic improvement. We describe two patients who presented with symptoms consistent with gastro-oesophageal reflux, unresponsive to medical management. After fundoplication both developed symptoms of profound gastric motor dysfunction and subsequently proceeded to near-total gastro-oesophageal with symptomatic improvement. Histological examination of both excised gastric specimens revealed eosinophilic mural gastritis. To our knowledge, these are the first cases to demonstrate the association of mural eosinophilia and symptomatic gastric motor dysfunction. We propose that patients with gastric motor dysfunction, refractory to medical management, progress to laparoscopy and mural biopsy before gastrectomy. This would allow histological analysis of the gastric wall, and in the event of a positive finding of mural eosinophilic gastritis would allow a trial of medical therapy that could include an eosinophilic stabilizer such as the leukotriene D4 receptor antagonist montelukast or intravenous corticosteroid therapy, which may alleviate the symptoms.

Eosinophilic gastroenteritis

Eosinophilic gastroenteritis despite its uncommon occurrence is one of the most important primary eosinophilic gastrointestinal disorders, and most commonly presents with abdominal pain. The terminology is, however, misleading because all levels of the gastrointestinal tract from the esophagus to the rectum may be affected. A history of atopy and allergies is present in 25-75% cases. The heterogeneity in the clinical presentations of EG is determined by the site and depth of eosinophilic infiltration. Eosinophilic intestinal inflammation also occurs secondarily in the gastrointestinal tract in inflammatory bowel disease, autoimmune diseases, as reactions to medications, infections, hypereosinophilia syndrome, and after solid organ transplantation. Recent investigations providing an insight into the pathogenesis of eosinophilic gastroenteritis support a critical role for allergens, eosinophils, Th-2 type cytokines, and eotaxin in mediating eosinophilic inflammation. The diagnosis is confirmed by demonstrating prominent tissue eosinophilia on histopathology. Treatment recommendations based on data extrapolated from retrospective, uncontrolled studies, and expert opinion support the use of restricted diets, corticosteroids, leukotriene receptor antagonists, and mast cell stabilizers. Many unanswered questions remain with regard to the natural history, optimal duration of therapy, safer steroid-sparing long-term treatment agents, and the means of reliable and non-invasive follow-up.

Gastrointestinal food allergy: new insights into pathophysiology and clinical perspectives

Adverse reactions to food that result in gastrointestinal symptoms are common in the general population; while only a minority of such individuals will have symptoms due to immunologic reactions to foods, gastrointestinal food allergies do exist in both children and adults. These immune reactions are mediated by immunoglobulin E-dependent and -independent mechanisms involving mast cells, eosinophils, and other immune cells, but the complexity of the underlying mechanisms of pathogenesis have yet to be fully defined. Knowledge of the spectrum of adverse reactions to foods that affect the digestive system, including gastrointestinal food allergy, is essential to correctly diagnose and manage the subset of patients with immunologically mediated adverse reactions to foods. Potentially fatal reactions to food necessitate careful instruction and monitoring on the part of health care workers involved in the care of individuals at risk of anaphylaxis. New methods of diagnosis and novel strategies for treatment, including immunologic modulation and the development of hypoallergenic foods, are exciting developments in the field of food allergy.

Sonography in diagnosis and follow-up of serosal eosinophilic gastroenteritis treated with corticosteroid

An 18-year-old patient presented with abdominal pain, nausea, and low-grade fever. Sonography showed ascites in the region of the terminal ileum, and the presence of peritoneal nodules suggested peritoneal inflammation. Cytologic analysis of ascites revealed numerous eosinophils. Sonographic visualization of nodular peritoneal deposits associated with eosinophilic ascites permitted the diagnosis of the serosal form of eosinophilic gastroenteritis. The absence of mucosal and muscular involvement in the bowel wall was confirmed by endoscopy and CT. Two weeks of 20 mg/day oral prednisolone led to relief of the patient's symptoms, with normalization of laboratory parameters and sonographic findings.

The pathobiology of eosinophilic gastroenteritis of childhood: is it really the eosinophil, allergic mediated, or something else?

Over the past decade clinicians have witnessed a dramatic rise in the prevalence of eosinophilic gastrointestinal diseases. Diverse symptoms, a broad range of endoscopic findings, and varying histopathologic features pose several questions: Do eosinophils represent an allergic response? What mechanisms drive eosinophils to specific mucosal targets? How do eosinophils affect the gastrointestinal tissues? Recent clinical and basic studies are investigating the pathogenesis of eosinophilic gastrointestinal diseases. This review highlights the literature concerning the mechanisms that govern these diseases, with a specific focus on diseases of gastrointestinal columnar epithelia (eosinophilic gastroenteritis and eosinophilic colitis). The roles of specific chemokines, such as eotaxin, and the data supporting the involvement of eosinophil granule proteins in disease states, are discussed.

Clinical efficacy and pharmacokinetics of montelukast in dyspeptic children with duodenal eosinophilia

BACKGROUND

Montelukast, a competitive cysteinyl leucotriene-1 receptor antagonist, reduces airway eosinophilia in asthmatics. We evaluated the effect of this drug in children with eosinophilic duodenitis, defined histologically as duodenal mucosa with peak eosinophil count of more than 10 eosinophils/hpf.

METHODS

Forty children and adolescents (6-18 yr) with dyspepsia and duodenal eosinophilia were enrolled in a double blind, randomized, placebo-controlled, cross-over study of monteleukast therapy. Subjects were randomized to receive either 10 mg montelukast or an identical placebo once daily and were evaluated on day 14 for symptomatic and biochemical responses. Subjects were also randomized to one of two blood sampling schemes to evaluate montelukast pharmacokinetics.

RESULTS

Using a post treatment global pain assessment, a positive clinical response was observed in 62.1% of patients receiving montelukast compared with 32.4% on placebo (p < 0.02). Pain assessment score deteriorated in 45% of montelukast responders (5/11) after cross-over to placebo and improved in 62% (8/13) of placebo non-responders on cross-over to montelukast. In patients with peak duodenal eosinophil counts between 20-29/hpf (n=19), a positive pain assessment response was observed in 84% of patients receiving montelukast compared to 42% receiving placebo (p < 0.01). Response rate did not differ by age, gender or histologic findings at baseline. Pharmacokinetic analysis yielded parameter estimates for absorption rate constant (Ka), apparent volume of distribution (Vd/F) and elimination rate constant (Kel) of 0.42 h, 0.19 L/kg and 0.26 h, respectively. The relative extent of systemic drug exposure was comparable to that observed in previous pediatric investigations with similar weight-adjusted montelukast doses. Neither dose nor calculated drug exposure were associated with the level of post treatment pain assessment or the change in biochemical markers.

CONCLUSIONS

These data suggest a beneficial role for montelukast in the treatment of pediatric patients with dyspepsia associated with duodenal eosinophilia.

The physiological and pathophysiological roles of eosinophils in the gastrointestinal tract

Eosinophils and the gastrointestinal tract interact in an intimate and enigmatic relationship. Under healthy conditions, the presence of eosinophils is limited almost exclusively to the digestive tract mucosa where they exert several effector and immunoregulatory functions. While their precise function in the gastrointestinal tract is not completely understood, it is likely that, together with different T cell subsets, eosinophils are involved in maintaining the immunologic homeostastis across the mucosal barrier under resting conditions. Eosinophils also play a role in several inflammatory conditions, such as intestinal infections, hypersensitivity reactions, primary eosinophilic inflammations and several other chronic intestinal disorders. Depending on the responsible trigger, their effects may be beneficial or detrimental. Here, we discuss the available information regarding the physiological and pathological functions of eosinophils within the gastrointestinal tract.

Chronic eosinophilic ascites in a very young child

A case of chronic eosinophilic ascites with onset in early infancy is described. An intensive diagnostic work-up ruled out other known causes of ascites in childhood. The final diagnosis was made at 2 years of age when a large number of eosinophils was detected in the ascitic fluid. The outcome was complicated by an ex vacuo intraperitoneal haemorrhage. Steroids were able to control the disease only after complete aspiration (1600 ml) of the ascitic fluid. On discontinuation of treatment, peritoneal inflammation recurred indicating steroid-dependency.

CONCLUSION

eosinophilic ascites, a very rare disorder in children, should be considered in the differential diagnosis of even very young children presenting with ascites.