Achalasia

Achalasia is a disorder of esophageal motility characterized by esophageal aperistalsis and failure of the lower esophageal sphincter relaxation. The disease is progressive, resulting in gradual dilatation of the esophagus above the sphincter. Successful treatment of the disease by repeated esophageal bougienage was first described by Willis in 1674. Cardiomyotomy, the basis of modern surgical treatment for achalasia, was introduced by Heller in 1914. Despite advances in its treatment, the initiating factors and the underlying mechanisms of achalasia are still not well understood.

Achalasia is a rare condition that affects boys and girls equally. Achalasia may be primary (idiopathic) or secondary. Secondary achalasia shares clinical features with primary achalasia, but there is an identifiable cause. Primary achalasia has an estimated prevalence of 0.5–1 per 100,000 per year without a clear age predilection. Only less than 5% of all cases present before the age of 15 years. Epidemiology studies have revealed a small incidence peak in the 20–40 years age group. These, together with the rare occurrence of familial cases and syndromic associations, have led to the postulation of a possible hereditary factor for the disease. Recent work has also suggested a role for changes in neurotransmis-sion and cell signaling in the lower esophagus as a possible pathophysiological mechanism.