Achalasia is a disease of unknown aetiology which is characterized by aperistalsis in the body of the oesophagus and failure of relaxation of the LOS on initiation of swallowing.
Degenerative lesions are found in the vagus as well as a decrease in ganglionic cells in the nerve plexus of the oesophageal wall.
The disease can present at any age but is rare in childhood. The incidence is about 1 : 100000 per year. Patients usually have a long history of intermittent dysphagia for both liquids and solids. Regurgitation of food from the dilated oesophagus may be induced by the patient or may occur spontaneously, particularly at night, and aspiration pneumonia may result. Occasionally food gets stuck but patients often learn to overcome this by drinking large quantities, thereby increasing the head of pressure in the oesophagus and forcing the food through. Severe retrosternal chest pain occurs particularly in younger patients with vigorous non-peristaltic contraction of the oesophagus. The dysphagia in these patients can be mild and the pain misdiagnosed as cardiac in origin. Weight loss is usually not marked.
A CHEST X-RAY may show a dilated oesophagus, with an occasional fluid level, behind the heart. The fundal gas shadow is not present.
A BARIUM SWALLOW will show dilatation of the oesophagus, lack of peristalsis and often synchronous contractions. The lower end gradually narrows (beak deformity); this appearance is due to failure of the sphincter to relax.
OESOPHAGOSCOPY is necessary to exclude a carcinoma at the lower end of the oesophagus, as this can produce a similar X-ray appearance. When there is marked dilatation, extensive cleansing is necessary to remove food debris in.order to obtain a clear view. In achalasia the oesophagoscope easily flops through the apparent narrowing without resistance.
MANOMETRY is used to measure oesophageal motility. It shows aperistalsis of the oesophagus as well as the failure of relaxation of the LOS . Chagas’ disease (American trypanosomiasis, damages the neural plexus of the gut and produces a similar clinical picture.
The LOS is dilated forcibly using a pneumatic bag (passed under X-ray control) so as to weaken the sphincter. This is successful in 80% of cases. Surgical division of the muscle at the lower end of the oesophagus (cardiomyotomy or Heller’s operation) is now being performed laparoscopically. Reflux oesophagi tis complicates both procedures and the aperistalsis of the oesophagus remains. In older patients, nifedipine (20 mg sublingually) can be tried initially.
There is an increased incidence of 5-10% of carcinoma of the oesophagus in both treated and untreated cases.