eosinophilic esophagitis

A first step in addressing EoE should be to eliminate primary GERD or PPI responsive esophageal eosinophilia. This is done by using proton pump inhibitors (PPI’s) at doses of 20-40 mg, 1-2/daily for 8-12 weeks in adults and 1 mg/kg per dose, twice daily for 8-12 weeks in children. This treatment is effective when esophageal eosinophilia is due to GERD.

There is a subset of patients with primary EoE and secondary GERD. These patients may or may not meet conventional pH criteria for diagnosing reflux. In these patients, PPI’s alone are not sufficient to treat EoE.

Dietary management is a mainstay of EoE treatment. It is extremely effective in children, with near-complete resolution of symptoms and histological abnormalities. Strict use of amino acid based formula, dietary restriction based on extensive allergy testing, and elimination of most likely allergens have all been used. Elemental therapy is the most effective. Food tolerance is unlikely to be achieved, even after long term elimination. Methods at achieving food tolerance in EoE patients have not been well studied.

Corticosteroids are effective in adults and children, but disease almost always recurs even stopped. Systemic steroids should be used in emergencies only due to the host of long term problems associated with chronic use. Topical steroids are usually effective, but steroid resistance has been reported and local fungal infections can occur. Fluticasone and oral viscous budesonide have been effective in studies. Budesonide can potentially reverse esophageal fibrosis.

Some medications used to manage mast cells, which are often elevated in EoE patients, have been trialed for EoE. Cromolyn sodium has not apparent therapeutic effect for EoE patients. Leukotriene receptor antagonists might be effective at high dosages, but this is unclear. One study on TNF-a blocker did not show benefit. Disappointingly, clinical response to anti IL-5 was variable. Anti-IL-5, anti-IL-13 and anti-eotaxin are possible future therapies.

Food impaction, in which food is retained in the esophagus, requires emergency intervention. This has been found to occur in 11-55% of EoE adults across multiple studies.

Esophageal rings are commonly found in EoE patients and inherently imply stricturing. Strictures larger than 1 cm are found in 11-31% of adults with EoE. 10% of adults have narrow caliber esophagus.

19 patients with EoE have reported perforations that were spontaneous or not due to dilation. Of 14 of these, two suffered full perforations, in which esophageal or gastric contents were found in the chest cavity. Surgical intervention was required. The remaining 12 patients had partial perforations, in which limited air or contrast media moved into the mediastinum from the esophagus. Five patients had partial perforations following endoscopy without dilation. Of the 19 total, 7 needed surgery. None were fatal.

Three instances of circumferential intramural dissection have been noted, and many cases of intramural tearing, either spontaneous or subsequent to endoscopy. Intramural tears are deep lacerations reaching the esophageal submucosa. Circumferential intramural dissection occurs where the esophageal lumen comes away from the esophageal wall in a way that affects a contiguous ring.

There is no evidence that esophageal cancer or generalized EGID results as a complication or progression of EoE. Six patients have reported concurrent Barrett esophagus. However, merely having EoE is not predictive for Barrett esophagus.

Dilation is still considered controversial in the management of EoE with high grade stricturing. This is in part because of a study done before 2008 that found that in a group of 84 adults, 5% suffered perforation and 7% hospitalized for chest pains following the procedure. These rates are much higher than in patient groups who underwent dilation for non-EoE reasons. However, three more recent retrospective studies reported lower rates of complications. Of 404 patients who underwent 839 dilations, only 3% of procedures resulted in perforations – a rate of 0.8%. Perforations were partial and did not require surgery. Chest pain occurred in 5%. One patient had major bleeding that required intervention. Dilation can induce long lasting relief from dysphagia when high grade stricturing is present. Many patients have reported a preference for periodic stricturing rather than daily medication or food elimination.

References:

Liacouras, Chris A., et al. Eosinophilic esophagitis : Updated consensus recommendations for children and adults. J Allergy Clin Immunol 2011, pp. 3-20.

Furata, Glenn T., et al. Eosinophilic esophagitis in children and adults: a systematic review and consensus recommendations for diagnosis and treatment. Gastroenterology 2007; 133:1342-1363.

Diagnosis of EoE can be difficult. Endoscopy with biopsy is the only reliable method currently available. Often in these patients, the esophagus may look unremarkable, so biopsies are recommended regardless of gross appearance. 2-4 biopsies from the proximal and distal esophagus should be collected. Biopsies of the gastric antrum and duodenum may also be taken to rule out other conditions.

Fibrosis of the lamina propria is present in most biopsies of both child and adult patients. Though less prevalent, this finding is still found sometimes in GERD cases. Basal zone hyperplasia, elongation of rete pegs and dilated intercellular spaces are EoE associated findings. Additionally, mast cells are increased in biopsies from EoE patients more so than GERD patients. IgE bearing cells are found more often in EoE than GERD.

There is some dispute over whether the peak value (the cell count in the single high powered field with the most eosinophils) is more representative than the average value (the average of cell counts in several high powered fields.) Some studies have found a correlation between eosinophil count and symptom presentation, while others have not. There are also some patients with active eosinophilic inflammation in the esophagus with few symptoms.

Other diagnostic methods should be included to rule out other conditions.   Esophageal manometry and pH testing in EoE children demonstrated that dysfunctional peristalsis correlated with difficulty swallowing. Esophageal manometry with pressure topography can reveal abnormal pressurization patterns in EoE that are not found in GERD. Endoscopic ultrasound has shown thickening of both the muscles and the mucosa in EoE. Impedance planimetry, a method that measures both pressure and volume changes, has recorded significant changes in compliance and distensibility of the esophageal wall in EoE patients. Barium contrast swallow testing was normal in 12/17 children with EoE, including four who had required endoscopy for food impaction. X-ray can detect stricturing of the proximal cervical esophagus. Some studies have linked motility issues to EoE, while others have found the opposite.

pH testing is usually undertaken to exclude GERD. In multiple studies, transnasal and wireless capsule pH measuring systems have shown variability in acid pH. When coupled with impedance testing, pH testing seems to correlate better with symptoms, but this has not been fully investigated yet. In children, both acid and non-acid reflux is comparable to controls.

40-50% of EoE patients have an increase in circulating eosinophils. When EoE is effectively treated with topical corticosteroids, peripheral eosinophilia has been shown to decrease. One study noted that in EoE patients, esophageal eosinophils display HLA DR, which means that they act as antigen presenting cells. Antigen presenting cells recruit other cells in the immune system and generate a strong inflammatory response.

Periostin, an extracellular matrix protein, is increased in the esophagus of EoE patients. Importantly, it correlates with eosinophil levels in EoE patients. Expression of eotaxin 1 and 3 is also increased in EoE. Fibroblast growth factor 9, IL-13, IL-15 and TGFB-1 can be elevated in both EoE and GERD.

A crucial finding in EoE research was the characterization of a signature transcriptome, which measures which genes the cells are using and which proteins they are making. This transcriptome is distinct from nonspecific chronic esophagitis, which has a peak eosinophil count or 6 or fewer eosinophils/hpf. Studies have demonstrated that the transcriptome can distinguish from GERD. Eotaxin 3 is hugely overexpressed in EoE patients. IL-13 is also overexpressed, with data to indicate that it may be the key regulator in EoE disease processes. In patients who have successfully achieved symptom remission, abnormal gene expression has returned to normal. However, some genes in epithelial cells continue to be expressed abnormally, which may factor into relapse.

Genetic studies have revealed that the first genome wide susceptibility locus for EoE is at 5q22. The study that found this common variable included 550,000 common genetic variants collected from various institutions. In this susceptibility locus lie genes associated with thymic stromal lymphopoietin (TSLP), a cytokine that influences behavior of Th2 cells. In a second study that looked at 53 potential genes that affected allergic or epithelial responses, or both, the TSLP gene was also identified as a susceptibility locus for EoE. This continued to be true when the data was controlled for atopic conditions. The TSLP receptor gene on the X chromosome has also been tied to EoE in male patients. These findings make a strong case for EoE as a Th2 mediated disease.

Another genetic factor found to be overrepresented in EoE patients was a common deletion variant in the filaggrin gene, 2282del4. This mutation has been associated strongly with atopic dermatitis. However, even in EoE patients who don’t have atopic dermatitis, this genetic variant is found more frequently than in the general population.

References:

Liacouras, Chris A., et al. Eosinophilic esophagitis : Updated consensus recommendations for children and adults. J Allergy Clin Immunol 2011, pp. 3-20.

Furata, Glenn T., et al. Eosinophilic esophagitis in children and adults: a systematic review and consensus recommendations for diagnosis and treatment. Gastroenterology 2007; 133:1342-1363.

Eosinophilic esophagitis (EoE) is a well studied, well defined eosinophilic disease localized to the esophagus. With a few exceptions, it is usually diagnosed pathologically by a peak value of 15 eosinophils/hpf in esophagus biopsy samples. Currently, endoscopy with biopsy evaluation is the only diagnostic for EoE considered accurate, but patient symptoms must be considered to make a diagnosis.

EoE patients are mostly male, with three times more males than females affected. Most patients are atopic, with a history of other allergic conditions. EoE usually presents in childhood or in third or fourth decade of life, but can onset at any time.

Adult EoE patients present with more uniform symptoms. They have dysphagia (difficulty swallowing), food impaction and upper abdominal pain. About 15% of dysphagia cases are caused by EoE. Food impaction requiring endoscopic intervention occurs in 33-54% of EoE adults. Children with EoE have less specific symptoms and are more likely to have vomiting and generalized abdominal and chest pain.

As mentioned above, other atopic conditions are commonly found in EoE patients. 50-60% of EoE patients have had at least one atopic condition. 40-75% have allergic rhinitis, 14-70% have asthma and 4-60% have eczema.

15-43% of EoE patients have immediate IgE mediated food hypersensitivity reactions. Food induced anaphylaxis is more likely in EoE patients than in other populations. Furthermore, a history of IgE mediated food allergy is correlated with EoE in both adults and children.

Most EoE patients are sensitized to food allergens or aeroallergens as determined by skin prick testing or serum IgE values. Local IgE production and FceRI positive cells (cells that can be activated by IgE) are elevated in biopsies from EoE patients. Six separate articles have documented seasonality in symptom severity and presentation in EoE.

High amounts of eosinophils in the esophagus (esophageal eosinophilia) can be caused by a number of conditions in addition to EoE. This includes the broader classification of EGID, GERD, Celiac disease, Crohn’s disease, hypereosinophilic syndrome, achalasia, drug hypersensitivity, vasculitis, pemphigoid vegetans, connective tissue disease, graft versus host disease, and infection. It is necessary to effectively rule out these other conditions before diagnosing EoE, and this can be difficult. Particularly, it can hard to distinguish between EoE and GERD.

Some studies have reported that significant eosinophil driven inflammation occurs in the proximal esophagus of adults with EoE but not with GERD. Surface layering of eosinophils is more typical of EoE than GERD. Some reports indicate that extracellular eosinophilic granules, including eosinophil peroxidase, major basic protein and eosinophil derived neurotoxin, are more indicative of EoE than FERD.

The cut off of 15 eosinophils/hpf is also problematic for diagnosing EoE. Surface layering and microabscesses are only found when 15/hpf are present. Additionally, basal zone hyperplasia is 44% more likely with 15/hpf and over 100% more likely with 20/hpf. Some studies have found that a large proportion of adults meeting this threshold actually have GERD. Further confusing the issue, there is a growing subpopulation of GERD excluded patients diagnosed with EoE that demonstrate a response to PPIs. This situation is increasingly being referred to as PPI responsive esophageal eosinophilia rather than EoE.

References:

Liacouras, Chris A., et al. Eosinophilic esophagitis : Updated consensus recommendations for children and adults. J Allergy Clin Immunol 2011, pp. 3-20.

Furata, Glenn T., et al. Eosinophilic esophagitis in children and adults: a systematic review and consensus recommendations for diagnosis and treatment. Gastroenterology 2007; 133:1342-1363.