Snapshot A 41-year-old man presents to the clinic complaning of substernal chest pain and regurgitation of undigested food. He also reports having difficulty swallowing both solid and liquids. A barium esophgram demonstrates a dilated proximal esophagus with a narrow tapering. Introduction Motor disorder of the distal esophagus secondary to progressive degeneration of the Aurbach plexus (ganglion cells in the myenteric plexus) Epidemiology incidence of 1.6 cases per 100,000 individuals demographics occurs equally among men and women diagnosis occurs between ages of 25 and 60 years risk factors Chagas disease other diseases such as scleroderma (see etiology) Etiology the etiology of primary/idiopathic achalasia is unknown secondary achalasia occurs due to diseases that cause esophageal motor abnormalities Chagas disease: protozoan parasite Trypanosoma cruzi destroys intramural ganglion cells other diseases include amyloidosis, sarcoidosis, scleroderma, neurofibromatosis, Fabry disease, and eosinophilic esophagitis. Pathogenesis inflammation and degeneration of neurons of the Aurbach’s plexus the cause of the degeneration is unknown but may be autoimmune as suggested by the association with variants in the HLA-DQ regions in affected patients and the presence of antibodies to enteric neurons primarily leads to loss of nitric oxide-producing, inhibitory neurons that affect the relaxation of esophageal smooth muscle results in loss of normal relaxation of the lower esophageal sphincter (LES) and rise in basal sphincter pressure results in aperistalsis Prognosis disease is progressive without treatment that ultimately leads to end-stage achalasia characterized by esophageal tortuosity, angulation, and megaesophagus (diameter >6 cm) Presentation Symptoms dysphagia for solids and liquids regurgitation difficulty belching vomit heartburn/substernal chest pain weight loss Imaging Radiography may demonstrate mediastinal widening Barium esophagram not a sensitive test for achalasia, as it may be interpreted as normal in up to 1/3 of patients positive findings include 1) dilation of the proximal esophagus 2) “bird-beak” appearance at the esophageal sphincter 3) aperistalsis 4) delayed emptying of barium Upper endoscopy may reveal dilated esophagus that contains residual material esophageal mucosa usually appears normal often performed after esophageal manometry to rule out malignancy Esophageal manometry gold standard - required to establish diagnosis high-resolution manometry (vs. conventional manometry) allows for categorization of the achalasia subtype, which can guide management findings include increased LES pressure, inability of the LES to relax, decreased peristalsis, and diffuse esophageal spasm Differential Gastroesophageal reflux disease (GERD) distinguishing factor regurgitated food is typically sour tasting in GERD due to the presence of gastric acid will have nonspecific findings on manometry Pseudoachalasia due to malignancy distinguishing factor may have the same manometry findings but can be differentiated from achalasia via upper endoscopy Cardiovascular dysphagia distinguishing factor compression of the anterior esophagus by enlarged left atrium of the heart normal manometry findings Treatment Medical management Botulism toxin injections High initial success but have more frequent relapses and a shorter time to relapse compared to operative treatments often second-line therapy offered to patients who are high risk for complications pharmacological treatments (e.g., nifedipine, nitrates, or calcium channel blockers) are often ineffective and are limited by side effects indicated in patients who fail treatment with botulism toxin Operative preferred option for patients who have average surgical risk though the efficacy of treatments decreases over time 1/3 to ½ of patients will require repeat treatment within 10 years endoscopic balloon dilation of LES Cure rate of 80% Complication of perforation in <3% of patients myotomy with fundoplication Similar outcomes to that of dilation peroral endoscopic myotomy (POEM) new endoscopic technique that allows for myotomy of more proximal esophageal muscle Complications Esophageal carcinoma ↑ risk of esophageal squamous cell carcinoma secondary to chronic irritation from food stasis ulceration and bleeding