Achalasia

• Disease Site
• Incidence
• Predisposing Factors
• Macroscopic Features
• Microscopic_Features
• Natural History
• Clinical History
• Clinical Examination
• General Investigation
• Specific Investigations
• Prognosis
• Treatment Overview
• References

Disease Site

Achalasia is a disorder of the oesophagus (the tube that carries food from the mouth to the stomach). The oesophagus is less able to move food toward the stomach and the valve from the oesophagus to the stomach does not relax during swallowing. This relaxation is needed to allow food to enter the stomach.

To the right is a picture of the gastroesophageal junction valve that usually relaxes to allow passage of food, and then closes to prevent reflux. As seen in this image, the sphincter is very tightly closed and thus would not adequately allow the passage of food.

Incidence

It affects men and women equally between the ages of 30-60. It can also occur in infancy and childhood. The incidence is 1 in 100,000/year.

Predisposing Factors

Most commonly the cause is unknown (idiopathic). However, achalasia can also develop as a result of damage to the nerves to the oesophagus. This is seen in chronic Chagas disease – a condition common in South America which is caused by the Trypanosoma cruzi parasite.

Macroscopic Features

A dilated oesophagus above the lower oesophageal sphincter. The wall of the oesophagus may be thickened (due to increased muscle in the wall) or thinned (from the pressure of the distension). There is also diminished myenteric ganglia (nerve fibres) and secondary damage to the mucosa (lining).

Microscopic Features

Microscopy of the lower segment may reveal ulceration and inflammation with fibrosis.

Natural History

Achalasia is a progressive disease meaning patients will gradually experience increasing difficulty when swallowing. Medical treatment may alleviate symptoms but they do not provide a long term solution.

Most patients require surgical intervention. Those who are treated early (before marked dilation) may avoid complications of oesophageal ulceration, oesophageal candidiasis, and aspiration pneumonia. There is also a slight increase in the risk of oesophageal carcinoma (cancer of the oesophagus).

With successful myotomy (surgery dividing the abnormal muscle in the lower sphincter of the oesophagus), patients are able to gain weight and lead a normal life. Some will develop gastro-oesophageal reflux, especially after surgery, which responds to medical treatment. Some recommend endoscopic monitoring due to the increased risk of oesophageal carcinoma.

Clinical History

Difficulty swallowing (dysphagia) is often intermittent (occurring every now and then), but becomes progressive. It affects solids and liquids equally, as opposed to other causes which more commonly affect solids first, then liquids.

Patients may develop other symptoms, such as:

• Regurgitation: Undigested foodstuffs (especially during sleep);
• Halitosis (bad breath);
• Retrosternal chest pain.

Complications are:

• Nutritional: Progressive weight loss;
• Respiratory: Repeated bouts of aspiration may lead to the development of interstitial pneumonitis and subsequent pulmonary fibrosis;
• Oesophageal erosions;
• Squamous cell carcinoma (late complication).

Clinical Examination

There are no specific findings on examination. Some patients may lose weight and appear emaciated. The presence of an irregular pulse or signs of congestive heart failure (especially right sided) may suggest chronic Chagas’ disease.

General Investigation

• A chest x-ray may show an enlarged oesophagus or a “fluid-level” behind the heart but it is not an accurate test for diagnosing achalasia.
• An endoscopy can be done to exclude other causes of dysphagia – such as a benign stricture secondary to reflux disease or a carcinoma (malignancy or cancer).

Specific Investigations

A Barium swallow (an x-ray of the throat and oesophagus) shows abnormal motility, a dilated oesophagus above a smooth, narrow distal stricture (“rat-tail”) as indicated in the image below. The oesophagus above the blockage (at the sphincter) has dilated due to gradual stretching by retained food.

Manometry is used to measure oesophageal motility. It shows absence of peristalsis of the oesophagus as well as failure of the lower oesophageal sphincter to relax.

Prognosis

Surgery often results in longer lasting relief of symptoms, while dilation alone (done at endoscopy) often results in only temporary improvement in symptoms. There is a slightly increased risk of oesophageal cancer.

Treatment Overview

Dilatation (widening) of the lower oesophagus during an endoscopy is satisfactory in over 80% of patients. This treatment can be complicated in some cases with aspiration pneumonia, reflux, re-stenosis (recurrence of the achalasia) and, in rare cases, oesophageal rupture.

Surgery

Heller’s operation – the surgical division of the abnormal muscle layer in the lower oesophagus. Often a Nissen fundoplication (the strengthening of the “valve” between the stomach and the oesophagus by wrapping the upper portion of the stomach, or fundus, around the bottom of the oesophagus) is done at the same time due to the high incidence of post-operative reflux oesophagitis.

References

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5. Kumar P, Clark M (eds). Clinical Medicine (5th edition). Edinburgh: WB Saunders Company; 2002. [Book]
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8. MedlinePlus [online]. Achalasia [cited 19 September 2018]. Available from: URL link
9. Raftery AT. Churchill’s Pocketbook of Surgery (2nd edition). London: Churchill Livingstone; 2001 [Book].