Epidemiology

• Achalasia tends to present in adult life between the ages of about 25 and 40 years with less than 5% occurring in children.
• A study of achalasia in Cardiff between 1926 and 1977 found an incidence of 4-6 per million.^[2]
• One of the study authors also looked at Nottingham between 1966 and 1983 and found an incidence of 0.5-1 per 100,000.^[3]

Presentation

• The most common presenting feature is dysphagia. This affects solids more than soft food or liquids.
• Regurgitation may occur in 80-90% and some patients learn to induce it to relieve pain.
• Chest pain occurs in 25-50%. It occurs after eating and is described as retrosternal. It is more prevalent in early disease.
• Heartburn is common and may be aggravated by treatment.
• Loss of weight suggests malignancy (may coexist).
• Nocturnal cough and even inhalation of refluxed contents is a feature of later disease.
• Examination is unlikely to be revealing although loss of weight may be noted. Rarely, there may be signs of an inhalation pneumonia.

Investigations

• Chest X-ray(CXR):
  • May possibly show signs of inhalation.
  • The classical picture of a CXR in achalasia shows a vastly dilated oesophagus behind the heart, but this is rarely seen in practice.
  • The gastric air bubble may be small or absent.
    
    
    
• Barium swallow:
  • Usually precedes endoscopy when investigating dysphagia as it is very easy to perforate a malignancy with an endoscope.
  • The barium swallow in achalasia is characteristic. The oesophagus is dilated, and contrast material passes slowly into the stomach as the sphincter opens intermittently. The distal oesophagus has a narrow segment and the image resembles a bird's beak. This is in contrast to the rat's tail appearance of carcinoma of oesophagus. In the early stages radiology can be normal.
• Manometry of the oesophagus:
  • Manometry is the gold standard for diagnosis of achalasia.^[4]
  • May show diagnostic features; there is a high resting pressure in the cardiac sphincter, incomplete relaxation on swallowing and absent peristalsis.
  • If manometry is normal but clinical symptoms or radiological evidence suggest achalasia, a condition called pseudoachalasia may be present. Causes include oesophageal and gastric malignancies and other tumours involving the distal oesophagus.^[5] Endoscopy with biopsy and CT can be helpful.
• Lower oesophageal pH monitoring:
  • May also be required to exclude gastro-oesophageal reflux disease (GORD) which often occurs with achalasia. If present it should mitigate against treatment by pneumatic dilatation (which causes about a 30% incidence of GORD).^[6]
• Endoscopy should be performed to exclude malignancy.

Differential diagnosis

• Other causes of dysphagia, including:
  • Carcinoma of oesophagus.
  • Oesophageal stricture.
  • Carcinoma of stomach, possibly involving the lower oesophagus.
  • Gastro-oesophageal reflux.
  • Plummer-Vinson syndrome (Patterson Brown-Kelly syndrome).
• A rare form may present in children in the first 6 months of life.^[7] The Rozycki syndrome is deafness associated with short stature, vitiligo, muscle wasting, and achalasia.^[8] Allgrove's syndrome is familial dysautonomia, glucocorticoid insufficiency, and defective tear formation.^[9]
• A condition rather like achalasia can develop as a complication of American trypanosomiasis (Chagas' disease). There is no aganglionic segment in this or in achalasia associated with diabetes and certain malignancies.

Management

• Calcium-channel blockers and nitrates may reduce pressure in the lower oesophageal sphincter but they are effective in only about 10% of patients and tend to be reserved for those who are unable to tolerate other forms of treatment.
• The best treatment is pneumatic dilatation. A balloon is inserted into the lower oesophagus via an endoscope and it is inflated to rupture the muscle of the oesophagus whilst leaving the mucosa intact. The success rate is 70-80% with a 5% rate of perforation. If a perforation occurs, emergency surgery is needed to close the perforation and perform a myotomy. About half of all patients will require more than one dilatation. Around a third of patients will develop significant gastro-oesophageal reflux. Pneumatic dilatation may be as effective as surgery.^[10]
• Endoscopic injection of botulinum toxin can be used but only 30% of patients have satisfactory relief at the end of 1 year.^[11] The injection can also produce an inflammatory reaction that will make surgery difficult. The technique is best reserved for the elderly and infirm who cannot tolerate dilatation or surgery.^[12]
• The Heller myotomy is the best treatment for those who are fit. Considering the usual age of presentation, that should be most patients. The operation can be performed via the laparoscope.^[13] The muscle fibres of the lower oesophagus are divided in a longitudinal direction for about 5 cms, about 1.5 cm above the stomach. The success rate is 85-95% but 10-15% suffer reflux.
• Operative failure may be met by repeat operation, dilatation or, in extreme circumstances, oesophagectomy.

Complications

• Untreated achalasia may lead to nocturnal inhalation of material lodged in the oesophagus and aspiration pneumonia.
• Treatment may cause perforation of the oesophagus.
• Treatment may lead to gastro-oesophageal reflux.
• Carcinoma of oesophagus:
  • Between 2% and 7% of patients with achalasia have carcinoma of oesophagus.
  • Longstanding disease increases the risk.
  • Presumably potential carcinogens are held in the oesophagus instead of being moved along.
  • Malignancy can develop even after treatment.
  • The best way to screen such patients for malignant change is uncertain as even in patients being observed, the mortality after malignant change is very high.^[14]