Posted on 18 Feb 2011 19:20
Achalasia is a disorder of the esophagus, the tube that carries food from the mouth to the stomach. It is characterized by enlargement of the esophagus, impaired ability of the esophagus to push food down toward the stomach (peristalsis), and failure of the ring-shaped muscle at the bottom of the esophagus, the lower esophageal sphincter, to relax.
The lower esophageal sphincter (LES) is a ring shaped band of muscle fibers located at the distal end of the esophagus where it meets the stomach. After food enters the stomach this ring of muscle contracts and creates a mechanical barrier to keep food and digestive acids from re-entering the esophagus. Normally, through peristaltic action initiated after swallowing, this ring relaxes to allow the food and fluids to pass through to the stomach. For people with achalasia, the LES does not relax very well. The failure of LES relaxation is due to damage to the nerves of the esophagus.
Achalasia is a rare disorder that is more common in older and middle-aged adults, which, although it can occur at any age, is usually diagnosed between 25 to 60 years of age. Although there have been some advances in understanding the physical cause of achalasia, its etiology is still unknown. Therefore, treatment is still entirely palliative 1,21
Principal Symptoms of Achalasia
- Reflux (regurgitation of food, fluids, and acids)
- Chest pain, which may increase after eating or may be felt in the back, neck, and arms
- Dysphagia - Difficulty swallowing food and liquids
- Difficulty belching
- Unintentional weight loss 1,2
Achalasia treatment is purely palliative. It is aimed at reducing the tone of the overactive LES, relieving any obstruction to food and liquids transiting the esophagus, and helping the esophagus to empty by gravity. The basic methods for this are muscle relaxants, chemical denervation (interruption of nerve supply by botulism toxin, for example), pneumatic dilation, or surgical myotomy. These methods vary in their level of invasiveness and risk of adverse effects. The general therapies are:
- Botulinum toxin (Botox) Injection. These injections are given to relax the sphincter muscles throught the action of the toxin
One injection of BT has been reported to relieve symptoms is almost 80% of patients. Fifty percent of these may remain symptom-free for up to six months. Others will need repeated injections or other treatment options.
However, overall, BT is recommended to be most effective in elderly patients, in whom dilation or surgery represent a high risk, or in patients with co-morbid illnesses who are not candidates for PD or myotomy and eventually an antibody is built up against the toxin, making it less effective.
- Long-acting nitrates or calcium channel blockers. These types of medications are mooth muscle relaxants that act by reducing LES pressure.
Nifedipine is one example of a calcium channel blocker that is well stuided for the treatment of achalasia, available in a sublingual formulation which helps it absorb rapidly and work quickly. Studies show that it takes 20 to 45 minutes for sublingual nifedipine to reach maximum effect so patients are advized to take the medication 30 to 45 minutes before meals and at bedtime. The efficacy of nifedipine is inconsistent in clinical studies, varying from 0% to 75%, with side effects reported by up to 30% of the patients.
Sublingual isosorbide dinitrate is an example of a nitrate that is effective in decreasing LES pressure in achalasia patients. This results in symptom improvement in 53% to 87% of patients. This medication works quicker than nifedipine but does not last as long thus patients are advised to take sublingual Isordil® 10 to 15 minutes before meals.
Other pharmacological agents that have been used are anti-cholinergics (atropine, dicyclomine, cimetropium, bromide), beta-adrenergic agonists (terbutaline), and theophyllin.
Unfortunately these agents rarely help longterm and are now only used in patient for whom pneumatic dilation or surgery is not possible. They can, however, be used while planning a more effective treatment.
- Pneumatic dilation (PD) is the most effective non-surgical treatment option for patients with achalasia. This procedure uses the air balloons to dilate the esophageal lumen and disrupt the circular muscle fibers of the LES. This is an outpatient procedure but there is still a small risk of perforation.
- Surgery (called an esophagomyotomy), may be used to decrease the pressure in the lower sphincter. Surgical management of achalasia involves performing a Heller myotomy (HM), combined with an antireflux procedure (Toupet or Dor).
Since there have been advances in pneumatic dilation and laparoscopic Heller myotomy, these two are the primary options for most patients with achalasia. Botulinum injection is more effective and usually reserved for the elderly or for those who cannot undergo pneumatic dilation or surgery. 1,2
Can Achalasia be Prevented?
There is nothing you can do to prevent the causes of achalasia since we do not know exactly what causes it. However, treatment can prevent the symptoms of the condition and so help protect you from longterm complications.