Achalasia - Disorders of the oesophagus

Achalasia

Definition

Achalasia is a disordered contraction of the oesophagus of neuromuscular origin.

Aetiology

Degeneration is seen in the vagus nerve associated with a decrease in ganglionic cells in the Auerbach’s nerve plexus within the oesophageal wall. Chagas’ disease in South America is very similar where infection by Try-panosoma cruzi causes destruction of the myenteric plexus.

Pathophysiology

The neuromuscular damage causes disordered motility along the whole length of the oesophagus. On manometry there is aperistalsis and incomplete relaxation of the lower oesophageal sphincter in response to swallowing. The gastrooesophageal sphincter classically remains tightly closed and there is dilation of the oesophagus.

Clinical features

Patients present with progressive dysphagia, regurgitation and nocturnal aspiration. Retrosternal burning pain occurs in around a quarter of patients. Patients are often underweight.

Complications

Patients may aspirate and develop respiratory symptoms. Achalasia may predispose to oesophageal carcinoma even after successful treatment (incidence of 5–10%).

Investigations

A chest X-ray may reveal a fluid level behind the heart. Diagnosis is made by barium swallow, which reveals a markedly dilated ‘megaoesophagus’. There may be superficial mucosal erosions with a very narrow passage of barium (rat’s tail) into the stomach through the contracted lower oesophageal sphincter.

24-hour pH and manometry studies can differentiate achalasia from other oesophageal motility disorders.

Upper gastrointestinal endoscopy is performed to exclude a tumour. Classically there is a dilated oesophagus containing food debris. The gastrooesophageal junction may or may not be tight. A normal upper gastrointestinal endoscopy does not exclude the diagnosis of achalasia. Biopsy reveals inflammation and mucosal ulceration in the oesophagus secondary to bacterial overgrowth.

Management

Patients require longterm treatment with a proton pump inhibitor. Treatment is by repeated dilatation of the lower oesophageal sphincter with a hydrostatic balzloon and/or injection of botulinum toxin into the lower oesophageal sphincter. Surgical intervention is indicated in those who fail to respond; a 10–12 cm incision is made into the anterior wall of the oesophagus without breaching the mucosa (Heller’s cardiomyotomy). Laparoscopic techniques are also used. Gastro-oesophageal reflux is a complication with both procedures.