EGJOO is a disorder in which the muscles of the esophagus (swallowing tube) do not function in a coordinated fashion so that swallowed material does not pass easily into the stomach. EGJOO often causes symptoms of swallowing difficulties and chest pain. The cause of EGJOO and its optimal treatment are not clear. The investigators research team suspects that EGJOO might be caused by an allergy that involves the esophagus, and that treatment with medications called corticosteroids might improve function of the esophageal muscles. The purpose of this study is to learn how corticosteroid therapy affects the muscles of the esophagus in patients suffering with EGJOO.

Esophagogastric junction outflow obstruction (EGJOO) is an esophageal motility disorder with a heterogeneous etiology. The optimal treatment for EGJOO is not known, and proper management of the condition remains disputed. Similar to patients with achalasia, patients with EGJOO exhibit poor relaxation of the lower esophageal sphincter (LES) with swallowing. Unlike patients with achalasia, however, those with EGJOO have some intact peristalsis in the esophageal body. Achalasia treatments (pneumatic dilation, Heller myotomy, per-oral endoscopic myotomy [POEM]) attempt to destroy LES muscle contraction function with myotomy inflicted by balloon distention (pneumatic dilation), diathermic needle-knife (POEM), or scalpel (Heller myotomy). With POEM and Heller myotomy, the incision extends into muscle of the esophageal body. These same interventions have been used to treat EGJOO, but an effective, non-invasive therapy that does not involve muscle disruption would be preferable, especially since EGJOO patients have evidence of esophageal body peristalsis that might be destroyed by achalasia myotomy techniques. The investigators Center for Esophageal Diseases has recently described a possible allergic etiology for achalasia and EGJOO in a study in which the investigators found profound mast cell degranulation in the LES muscle in all of 13 patients with these disorders who were treated with Heller myotomy. The investigators have also published reports outlining the investigators rationale for considering an allergic etiology for achalasia and EGJOO. Now, an extension of this work is to assess whether corticosteroid therapy, which can improve allergic conditions, can correct the esophageal dysfunction in EGJOO to the point that invasive and irreversible myotomy treatments might not be required. The proposed study will enroll subjects with clinically significant EGJOO on the achalasia-variant spectrum, and treat them with a 14-day course of oral, systemic corticosteroid therapy. The investigators aim to describe the symptomatic and manometric response to corticosteroid therapy, and hypothesize that the investigators findings might establish that a subset of patients with EGJOO have a reversible form of esophageal muscle dysfunction. Although long-term treatment with corticosteroids has unacceptable toxicity, identification of a reversible form of EGJOO with a short course of steroid therapy would suggest a therapeutic role for other, less toxic, allergy-directed therapies.

Inclusion Criteria: Adult patients age 18 years or older with the following clinical and diagnostic criteria will be eligible for study inclusion:

• EGJOO manometric diagnosis based on CC v4.0 criteria
• Primary symptom of dysphagia and/or non-cardiac chest pain
• Additional objective evidence of obstruction on Timed Barium Esophagram and/or EndoFLIP
• The treating physician has determined that invasive therapy (botulinum toxin injection, pneumatic dilation, POEM, or Heller myotomy) is indicated.

Exclusion Criteria:

• History of prior foregut surgery
• History of esophageal botulinum toxin injection within 6 months of study enrollment
• Presence of hiatal hernia > 2 centimeters
• Presence of esophageal mass
• Obstructing esophageal stricture or ring on endoscopy
• Reflux esophagitis (LA Grades B-D)
• Subjects on current immunosuppression or immune modulating therapy
• Chronic opioid use
• Previously diagnosed extrinsic compression of the gastroesophageal junction
• Concomitant Eosinophilic Esophagitis with uncontrolled mucosal disease who have not tried at least one standard therapy
• Contraindication to the use of oral corticosteroids
• History and/or current diagnosis of Diabetes