Achalasia: investigation and management.

Achalasia, characterised by the absence of peristalsis and failure of relaxation of the lower oesophageal sphincter, is an uncommon degenerative condition that results in dysphagia. If left untreated it can lead to aspiration, oesophageal perforation, oesophagitis and malnutrition. It has a range of immune, allergic, viral and genetic aetiological causes.