Oesophageal motility disorders
What are oesophageal motility or motor disorders?
The purpose of the oesophagus (gullet) is to transport food and liquids from the mouth to the stomach where they can be digested. Efficient and effective progress of food and liquids down the oesophagus requires a well coordinated pattern of sequence of movements to drive the food down from above and also to clear acid and bile, which can be refluxed up from the stomach.
A problem or disorder of the peristalsis or incomplete relaxation of the lower oesophageal sphincter can cause an oesophageal motor or motility disorder.
Achalasia is an ooesophageal motor disorder which was first described over 300 years ago. Achalasia accounts for most cases of oesophageal motor disorders. The annual incidence is roughly 1 to 2 per hundred thousand.
Achalasia can affect individuals of all ages, but is most often diagnosed in early to mid adult life.
The syndrome of oesophageal motility disorder also occurs in Chagars disease and sometimes is present along with the pseudo-obstructive syndrome of the intestine. Cancer can produce a paraneoplastic neural dysfunction and lead to achalasia. Oesophageal amyloidosis may also cause a form of achalasia.
Cause of achalasia
The aetiology or cause of achalasia is a failure or impairment of inhibitory neural control of the lower or distal oesophagus. This is the universal abnormality. The syndrome can also probably be caused by nerve damage at several other sites. The typical finding is of degeneration of myenteric inhibitory neurones which in the early stages is associated with inflammation in the tissues of the oesophagus.
The symptom that occurs in everyone with achalasia, or an oesophageal motility disorder, is difficulty swallowing solid food. This is known medically as dysphagia with solids. People with achalasia will complain that solid food such as bread, typically, will get stuck as it passes down the gullet. A very common symptom of achalasia is regurgitation. Interestingly the regurgitated food tastes bland because it has not entered the stomach. Some patients complain of a cramping chest pain particularly during an early phase of the disorder where increased contractions of the oesophagus occur.
The way that the symptoms develop over time varies from patient to patient. For example in some patients the symptoms can remain unchanged for many years, but in other patients the symptoms progress and worsen with increasing problems with regurgitation over several years. This is thought to be as a result of the development of a dilated oesophagus. If a dilated oesophagus results, and leads to problems with regurgitation, then lung problems and respiratory difficulties secondary to inhaled or aspirated oesophageal contents can result.
It is common for there to be a delay in making the diagnosis of idiopathic achalasia. On average there is a delay of two years from presentation of the first symptoms to diagnosis. There is especially likely to be a delay in diagnosis if oesophageal dilatation does not develop. The enlargement or dilation of the oesophagus can vary in degree from a very minor increase in size of the tube to an enormously enlarged oesophagus which can come to resemble the large intestine or colon.
Investigation of the disorder with a barium swallow will show oesophageal retention of barium with a gastro-oesophageal junction that tapers in a smooth fashion to a closed sphincter. There may be seen during the barium swallow occasional spurts of barium flow through the lower oesophageal sphincter into the stomach. If there is no dilatation of the oesophagus then the barium swallow may be reported as normal.
The only sensitive diagnostic test for achalasia or esophageal motility disorders is oesophageal manometry. It is quite common for manometry to be clearly diagnostic of achalasia when a barium study has been reported as normal.
It is important to distinguish between idiopathic achalasia (and achalasia-like states) and constriction or narrowing of the gastro-oesophageal junction by an infiltrating or encasing malignancy (cancer) at the cardia (the cardia is the medical or anatomical term for the part of the stomach that is attached to the esophagus). This diagnosis can be difficult to make. Therefore patients should be assessed carefully for any symptoms or signs suggestive of cancer and if there is any suggestion of malignancy, than upper gastrointestinal endoscopy should be performed and biopsies (tissue samples) of the lower oesophagus and cardia should be taken. A computer tomography scan is a useful investigation in this situation.
There are four ways of treating achalasia.
- Treatment with medication that relaxes the lower oesophageal sphincter.
- Mechanical disruption of the lower oesophageal sphincter by balloon dilatation.
- Mechanical disruption of the lower oesophageal sphincter by surgical myotomy.
- Pharmacological poisoning of the remaining excitedly nerves to the lower oesophageal sphincter with botulinum toxin.
Specialists in this area report that the results of lowering the sphincter pressure with drugs such as beta adrenergic agonists and calcium antagonists compare poorly with mechanical disruption of the lower oesophageal (LES) sphincter and by treatment with botulinum toxin.
Oesophagomyotomy is highly effective as a treatment. This surgical procedure is increasingly carried out as a laparoscopic or thoracoscopic procedure. Oesophagomyotomy is however associated with approximately a 5 to 10% risk of troublesome gastro-oesophageal reflux disease.
Balloon dilatation is an attractive treatment option because of its simplicity and low-cost. However the downside is that it often needs to be repeated and the results seem to vary from practitioner to practitioner. In some hands the procedure fails in up to 40% of patients, especially those who are younger.
Injection of the lower oesophageal sphincter with botulinum toxin is carried out during endoscopy of the oesophagus. This treatment is the most recently developed treatment. Botulinum toxin works by reducing the nervous activity of residual exciter in nerves and has the effect of reducing the lower oesophageal sphincter pressure. In the short term, the results are similar to balloon dilatation, but the procedure usually has to be repeated within 1 to 2 years. The toxin is also relatively expensive. However this is a simple, low risk procedure and is best used in patients who have significant other medical problems which make them unfit for oesophagomyotomy or lower oesophageal sphincter dilatation.
If a patient has oesophageal dilatation with their oesophageal motor disorder then it is important to treat the condition promptly to prevent worsening of the problem. If the oesophagus becomes badly or grossly dilated and the medical morbidity is high and the condition is very difficult to treat. It is possible to improve oesophageal emptying with effervescent drinks.
If the condition is effectively treated before major dilatation of the oesophagus is present, then the prognosis is excellent. Achalasia does carry a very significantly increased risk for cancer of the oesophagus up to many years later. This increased risk has been reported to vary from 2 to 7% in authoritative medical studies. There is no apparent lowering of this cancer risk with treatment. The average length of time from diagnosis of achalasia to development of cancer of the oesophagus has been estimated to be 28 years. It is therefore sensible for patients with achalasia to have regular screening endoscopy for cancer of the oesophagus. There is no need for patients with to follow a GERD diet unless they develop acid reflux or heartburn problems after treatment with oesophagomyotomy.