Esophageal disorders

MOTILITY DISORDERS AND DIVERTICULA

Oesophageal motility disorders

Achalasia

Pathology and aetiology
Achalasia (Greek ‘failure to relax’) is uncommon, it is due to loss of the ganglion cells in the myenteric (Auerbach’s) plexus, the cause of which is unknown. In South America, chronic infection with the parasite Trypanosoma cruzi causes Chagas’ disease, which has marked clinical similarities to achalasia. Histology of muscle specimens generally shows a reduction in the number of ganglion cells with a variable degree of chronic inflammation.
The physiological abnormalities are a non-relaxing LOS and absent peristalsis in the body of the oesophagus. With time, the oesophagus dilates and contractions disappear, so that the oesophagus empties mainly by the hydrostatic pressure of its contents. This is nearly always incomplete, leaving residual food and fluid. The ‘megaoesophagus’ becomes tortuous with a persistent retention oesophagitis due to fermentation of food residues , and this may account for the increased incidence of carcinoma of the oesophagus.

Clinical features

The disease is most common in middle life, but can occur at any age. It presents with dysphagia, although pain (often mistaken for reflux) is common in the early stages with heartburn. Patients often present late and, having had relatively mild symptoms, remain untreated for many years. Regurgitation is frequent, and there may be overspill into the trachea, especially at night.

Diagnosis

Achalasia may be suspected at endoscopy by finding a tight cardia and food residue in the oesophagus. Barium radiology may show hold-up in the distal oesophagus, abnormal contractions in the oesophageal body and a tapering stricture in the distal oesophagus, often described as a ‘bird’s beak’ . A firm diagnosis is established by oesophageal manometry. Classically, the LOS does not relax completely on swallowing, there is no peristalsis and there is a raised resting pressure in the oesophagus .

Treatment

Alone among motility disorders, achalasia responds well to treatment.
The two main methods are forceful dilatation of the cardia and Heller’s myotomy.
There is also Botulinum toxin endoscopic injection into the LOS. It acts by interfering with cholinergic excitatory neural activity at the LOS. The effect is not permanent, and the injection usually has to be repeated after a few months. For that its use is restricted to elderly patients with other comorbidities.
Drugs such as calcium channel antagonists have been used but are ineffective for long-term use. However, sublingual nifedipine may be useful for transient relief of symptoms .


Disorders of the body of the oesophagus
Diffuse oesophageal spasm is a condition in which there are incoordinate contractions of the oesophagus, causing dysphagia and/or chest pain. The condition may be dramatic, with marked hypertrophy of the circular muscle and a corkscrew oesophagus on barium swallow. These abnormal contractions are more common in the distal two-thirds of the oesophageal body.
There is no proven pharmacological or endoscopic treatment. Calcium channel antagonists, vasodilators and endoscopic dilatation have only transient effects. While the symptoms may be tolerated by most patients, sometimes the combination of chest pain and dysphagia is sufficiently severe that malnutrition begins. In these patients, extended oesophageal myotomy up to the aortic arch may be required.

Pharyngeal and oesophageal diverticula

Most oesophageal diverticula are pulsion diverticula that develop at a site of weakness as a result of chronic pressure against an obstruction. Symptoms are mostly caused by the underlying disorder unless the diverticulum is particularly large.
Traction diverticula are much less common. They are mostly a consequence of chronic granulomatous disease affecting the tracheobronchial lymph nodes due to tuberculosis, atypical mycobacteria or histoplasmosis. Fibrotic healing of the lymph nodes exerts traction on the oesophageal wall and produces a focal out pouching that is usually small and has a conical shape.

Zenker’s diverticulum (pharyngeal pouch) is not really an oesophageal diverticulum as it protrudes posteriorly above the cricopharyngeal sphincter through the natural weak point (the dehiscence of Killian). The exact mechanism that leads to its formation is unknown, but it involves loss of the coordination between pharyngeal contraction and opening of the upper sphincter. As the pouch enlarges, it tends to fill with food on eating. This leads to halitosis and oesophageal dysphagia.
Treatment can be undertaken endoscopically or can be done by open surgery involving pouch excision, pouch suspension and/or myotomy of the cricopharyngeus. All techniques have good results.

Mid-oesophageal diverticula are usually small pulsion diverticula of no particular consequence. The underlying motility disorder does not usually require treatment. Some pulsion diverticula may fistulate into the trachea, but this is more common with traction diverticula in granulomatous disease.

Epiphrenic diverticula are pulsion diverticula situated in the lower oesophagus above the diaphragm. They may be quite large, but cause few symptoms. They again probably reflect some loss of coordination between an incoming pressure wave and appropriate relaxation of the LOS. Large diverticula may be excised, and this should be combined with a myotomy from the site of the diverticulum down to the cardia to relieve functional obstruction.

Oesophageal infections

Bacterial infection of the oesophagus is rare, but fungal and viral infections do occur. They are particularly important in immunocompromised patients. Oesophagitis due to Candida albicans is relatively common in patients taking steroids (especially transplant patients) or those undergoing cancer chemotherapy. It may present with dysphagia or odynophagia. There may be visible thrush in the throat.
Endoscopy shows numerous white plaques that cannot be moved, unlike food residues. Biopsies are diagnostic. Treatment is with a topical antifungal agent.

Plummer–Vinson syndrome

This is also called the Paterson–Kelly syndrome or sideropenic dysphagia. Dysphagia is said to occur because of the presence of a post-cricoid web that is associated with iron deficiency anaemia, glossitis and koilonychia.
The classical syndrome is rarely complete. Some patients may have oropharyngeal leucoplakia, and this may account for an increased risk of developing hypopharyngeal cancer. Webs occur in the upper and middle oesophagus. Few require endoscopic dilatation.