Achalasia

What is it?
 

Achalasia is a rare swallowing disorder affecting the oesophagus in about one in every 100,000 people aged 25 to 60 years. It is a chronic disorder which worsens with time, and never resolves by itself. Patients have an increased risk of esophageal cancer, especially with long-standing untreated achalasia.

Causes
 

There are two underlying problems in achalasia

The lower oesophageal sphincter (LOS) remains closed, preventing liquids or food entering the stomach. The LOS is a circular muscle at the bottom of the oesophagus which is normally closed but should relax to open during swallowing, to let food enter the stomach.

The cause of these two problems is unknown, but one theory is that the nerve cells which cause the LOS to relax are somehow destroyed. Nerve destruction may also underlie the absence of propulsion in the lower oesophagus itself.

Symptoms
 

Initially, symptoms are mild, and the disorder progresses very slowly so that patients often seek medical help when already in the advanced stages.

The main problem is difficulty swallowing – at first just solids, but later even liquids and saliva. Food and saliva thus accumulate in the oesophagus, which becomes progressively more distended.

Weight loss, heartburn, regurgitation of food, globus (a sensation of fullness or a lump in the throat) hiccups, difficulty burping and chest pain are other symptoms.

The symptoms are usually clear, but some tests are needed to confirm the diagnosis, and to distinguish it from other conditions which seem similar, such as gastroeosophagel reflux disease (GERD) and pseudo-achalasia, a rare condition in which a tumour can give similar symptoms.

Tests
 

There are four important investigations to confirm achalasia

• Chest X-ray this basic test may show absence of air in the stomach (due to LOS spasm) and a distorted oesophagus. It may also reveal other chest pathology, for example tumours, lung disease.
• Barium swallow this essential test involves swallowing a barium mixture during X-ray screening. This clearly shows the shape, size and contraction (or lack of it) of the oesophagus.
• ManometryThis measure pressures within the oesophagus via a small tube introduced through the mouth or nose. When the tube is correctly placed, the patient is asked to swallow. Pressure readings usually show three abnormalities:
  • high resting LOS pressure (almost in spasm)
  • no LOS relaxation after swallowing
  • no peristalsis (propulsive contractions) in the lower oesophagus.
• Endoscopy in a sedated patient, a flexible tube with a camera is inserted into the oesophagus. Residual food is confirmed, inflammation and distortion of the oesophagus, possible ulcer and fungal infection can all be detected. Any suspicious spots can be biopsied.

The scope can also be passed into the stomach to check for stomach cancer, whose symptoms can mimic achalasia.

Treatment
 

There are three main categories of treatment, none of which can cure the underlying problem, but will provide significant relief of symptoms

1. Medical
   To reduce the LOS pressure, two methods are available
   
   
   • Nitrates & calcium channel blockers relax the sphincter muscle, but long-term use is usually unacceptable to patients because of side effects like headache and low blood pressure. They also become increasingly ineffective with time.
   • Botulinum toxin injected into the LOS paralyses it temporarily, relieving the spasm. This is often used for short-term symptom relief, but its long-term usefulness is unknown. This may also be used as a diagnostic test if achalasia is suspected.

2. Oesophageal dilatation
   Under anaesthesia, a special tube with a collapsed balloon is positioned (under X-ray guidance) in the oesophagus, and gradually inflated to break the spasm of the LOS. In the process, some of the LOS muscle fibres are torn, which prevents spasm recurring in the future. Check X-rays immediately afterwards for oesophageal perforation.
   Success rate: A single dilatation can give relief to 60 – 85% of patients. The process may be repeated after a few years, but if more than three dilatations are needed, other options should be considered.
   Possible complications include oesophageal perforation and gastric reflux due to excess tearing of the LOS rendering it totally ineffective.

3. MyotomyThis means cutting muscle fibres of the LOS. This can be done as a normal operation (through the chest or abdomen), or via an endoscope. Surgical myotomy (often with an anti-reflux procedure at the same time) in experienced hands gives good results. Sustained relief is recorded in about 85 percent of cases at 10 years, and 65 percent at 20 years after the procedure. Complications are few, but the cost and long recovery time must be considered. Endoscopic myotomy has been done for some time, but no long-term follow-up studies are available for comparison with the outcome of a conventional surgical approach.

(Dr AG Hall, Health24, January 2008)