Background

The term ‘achalasia’ comes from Greek, meaning ‘failure to relax’. It was first used by Sir Arthur Hurst early in the 20th century, although the clinical features were first described in 1697 by Thomas Willis. It is conventionally defined by the absence of peristalsis (this does not mean the absence of contractions) in association with a lower oesophageal sphincter (LOS) that fails to relax completely. High-resolution pressure topography recognises this classic type (type I) but also considers two other types of achalasia, where there can be either pan-oesophageal pressurisation to more than 30 mmHg with at least 20% of swallows (type II) or preserved fragments of distal peristaltic activity or premature (spastic) contractions with at least 20% of swallows (type III).² These last two types probably represent the entity usually referrred to as ‘vigorous achalasia’ when seen on conventional manometry. Primary or idiopathic achalasia needs to be considered separately from secondary achalasia. While symptoms may be similar, the presence of a specific aetiology can influence management. These secondary causes are discussed later in this chapter.

Primary achalasia

This is an uncommon condition with an incidence in the Western world that is probably less than 1 case per 100  000 people per year.³ It is due to progressive loss of ganglion cells in the myenteric plexus of unknown cause. The neural loss is somewhat selective as there is particularly severe loss of inhibitory nitrergic neurotransmission.^4,5 This process is often accompanied by an inflammatory infiltrate that has led to many theories regarding aetiology. While there is circumstantial evidence of viral exposure and autoimmune phenomena, neither provides a satisfactory explanation for all patients.⁵

Clinical features

The disease is most common in middle life, but can occur at any age. It typically presents with dysphagia and characteristically this affects fluids as well as solids. Symptom severity varies from day to day and patients often develop tricks to assist oesophageal emptying, such as Valsalva manoeuvres or air swallowing. Many admit to having been ‘slow eaters’ for many years. In patients who have remained untreated for many years, regurgitation is frequent and there may be overspill into the trachea, especially at night. In the early stages, achalasia may present with retrosternal discomfort and this may lead to a mistaken diagnosis of gastro-oesophageal reflux disease (GORD). Chest pain is common in achalasia and particularly so in those individuals said to have ‘vigorous achalasia’.

There are few physical signs that point specifically to any underlying motility disorder, including achalasia. There are two important areas of physical examination that should be carefully evaluated as positive findings will play an important part in management. A careful examination of the respiratory system is essential. Recurrent chest infections due to episodes of aspiration from an oesophagus that is unable to clear itself may lead to acute and chronic signs as pulmonary performance deteriorates. It is not rare for these patients to be labelled as asthmatic. The other important area is to make a careful assessment of the patient’s nutritional state. Insidious nutritional failure is easily missed in patients with a long history, although it is rare to see this in achalasia, where regular filling of the oesophagus with food and an upright posture eventually create a hydrostatic pressure that will overcome the LOS, allowing the oesophagus to partially empty.

Investigations

Most patients with dysphagia are offered endoscopy as their first investigation. While achalasia may be suspected at endoscopy by finding a tight cardia and food residue in the oesophagus, early or vigorous achalasia is easily missed as the oesophagus is not dilated and still contracts.

Barium radiology may show hold-up in the distal oesophagus, dilatation of the oesophageal body, peristaltic dysfunction and a tapering stricture in the distal oesophagus, often described as a ‘bird’s beak’. The gastric gas bubble is usually absent, because most patients cannot swallow air through their non-relaxing LOS. It should, however, be emphasised that, like endoscopy, these typical features of well-developed achalasia are often absent and radiology is frequently passed as normal.

A firm diagnosis can only be made by oesophageal manometry. High-resolution techniques suggest that conventional manometry, however, only diagnoses about a quarter of patients with achalasia on the basis of the classic features of a hypertensive lower oesophageal sphincter that does not relax completely on swallowing, aperistalsis of the oesophageal body and a raised resting pressure in the oesophagus (Fig. 16.1). The other two variants can be separated by the Chicago classification and this may be clinically relevant. Limited evidence suggests that patients with type II achalasia with pan-oesophageal pressurisation do respond well to treatment, but this seems not to be the case for type III.²

Treatment

Most patients with achalasia respond well to treatment. There is no reliable drug therapy. Patients can be treated by endoscopic botulinum toxin injection into the LOS, but the two main methods are forceful (pneumatic) dilatation of the cardia and operative cardiomyotomy. Very rarely, patients require oesophagectomy.