1

What is dysphagia?

Dysphagia represents difficulty in swallowing and is subclassified into:

a)

oropharyngeal dysphagia;

b)

oesophageal dysphagia.

Dysphagia can also be classified according to whether the difficulty in swallowing relates to solids, liquids or both, as this may help identify the aetiology (neuromuscular or obstructive).

It is important to distinguish dysphagia from:

a)

odynophagia – which represents painful swallowing;

b)

globus – which represents the sensation of a lump in the throat but with no underlying organic defect.

2

What are the common causes of oropharyngeal dysphagia?

Neuromuscular disease:

a)

central nervous system – cerebrovascular accident (CVA), Parkinson’s disease, multiple sclerosis (MS);

b)

peripheral nervous system – peripheral neuropathy;

c)

skeletal muscle disease – polymyositis, cricopharyngeal achalasia;

d)

myasthenia gravis.

Obstructive lesions:

a)

internal structural lesion:

i)

malignant stricture;

ii)

benign stricture – post-surgical or traumatic inflammatory narrowing;

iii)

Zenker’s diverticulum;

iv)

oesophageal web.

b)

extrinsic compression:

i)

anterior mediastinal mass;

ii)

cervical spondylosis.

3

What are the common causes of oesophageal dysphagia?

Oesophageal motility disorders:

a)

primary – achalasia, diffuse oesophageal spasm, hypertensive lower oesophageal sphincter (LOS), nutcracker oesophagus, ineffective oesophageal motility (IOM);

b)

secondary – scleroderma, diabetes, oesophageal carcinoma.

Obstructive lesions:

a)

internal structural lesion:

i)

malignant stricture;

ii)

benign stricture – secondary to gastro-oesophageal reflux disease (GORD), radiation, corrosive agents, drugs (including non-steroidal anti-inflammatory drugs, doxycycline, trimethoprim);

iii)

oesophageal web;

iv)

oesophageal ring (Schatzki’s ring);

v)

foreign body;

b)

extrinsic compression:

i)

anterior mediastinal mass – thoracic goitre, lymphadenopathy;

ii)

vascular lesion – thoracic aorta, left atrium, aberrant vessel (dysphagia lusoria).

4

Which diagnostic tests are performed to investigate a patient with dysphagia?

Barium swallow (Figure 1) – which can detect obstructive lesions and motility disorders. Double-contrast studies can also identify mucosal lesions.

Videofluoroscopy – which can identify neuromuscular causes of dysphagia.

Oesophagogastroduodenoscopy (OGD) – which can best detect oesophageal mucosal abnormalities, including oesophagitis and infection (Figure 2).

Nasopharyngoscopy – which can detect obstructive lesions and is indicated for patients with oropharyngeal dysphagia.

Chest radiograph (CXR) – which may detect an air-fluid level or identify evidence of aspiration pneumonia.

Manometry – which can detect oesophageal motility disorders.

pH monitoring – which can detect GORD.

Swallowing electromyography (EMG) – which can identify neuromuscular causes of oropharyngeal dysphagia.

Computed tomography (CT) imaging – which can detect structural lesions, including oesophageal carcinoma.

5

What are the principles of management in a patient with dysphagia?

History, examination and investigations to identify and treat the underlying cause.

Reduce the risk of aspiration by dietary modification, with food introduced according to viscosity and texture, such as pureed foods.

Nutritional and fluid supplementation – to reduce the risk of malnutrition and dehydration, including calorie supplementation, intravenous fluids, nasogastric feeding, percutaneous endoscopic gastrostomy (PEG) and total parenteral nutrition (TPN).

Physiotherapy – exercises for patients with underlying neuromuscular aetiology of dysphagia to reduce the risk of aspiration and develop some neuromuscular pharyngeal tone.

Oesophageal dilation or stent placement.

6

How are oesophageal motility disorders classified?

Primary oesophageal motility disorder:

a)

disorder of inhibitory innervation (relaxation) – which consists of vagal preganglionic neurons and myenteric plexus postganglionic neurons, which release nitric oxide and vasoactive intestinal peptide (VIP):

i)

achalasia (inadequate LOS relaxation);

ii)

diffuse oesophageal spasm (DOS);

b)

disorder of excitatory innervation (contraction) – which consists of vagal preganglionic neurons and postganglionic neurons, which release acetylcholine and substance P:

i)

hypotensive – hypotensive LOS or hypotensive peristalsis (ineffective oesophageal motility [IOM]);

ii)

hypertensive – hypertensive LOS or hypertensive peristalsis (nutcracker oesophagus).

Secondary oesophageal motility disorder – which represents an oesophageal manifestation of a systemic disease:

a)

disorders of inhibitory innervation (relaxation):

i)

secondary achalasia – carcinoma, lymphoma, Chagas disease (Trypanosoma cruzi);

b)

disorders of excitatory innervation (contraction):

i)

hypotensive – myotonic dystrophy, metabolic neuromyopathy (diabetes mellitus, alcohol), drugs (anticholinergics).

More recently, the Chicago classification of oesophageal motility disorders has been used, since the introduction of high-resolution oesophageal manometry (see Chapter 6 – Oesophageal function tests).

7

What is achalasia?

Achalasia is an oesophageal motility disorder characterised by the absence of peristalsis in the oesophageal body (pathognomonic) and impaired relaxation of the LOS, in response to swallowing.

It is the commonest primary oesophageal motility disorder and is caused by degeneration of the postganglionic inhibitory neurons in Auerbach’s myenteric plexus, which release vasoactive intestinal peptide (VIP) and nitric oxide.

Achalasia has an incidence of 5-10 per 1,000,000, primarily affecting adults between 25-50 years of age, with an equal male to female distribution.

Secondary achalasia can be caused by local infiltrative degeneration of the myenteric plexus in patients with oesophageal carcinoma, lymphoma or Chagas disease.

Pseudoachalasia is defined as the presence of clinical symptoms or radiographic evidence of achalasia in a patient with normal manometric findings. It can be caused by external compression of the gastro-oesophageal junction (GOJ).

8

What are the clinical features of achalasia?

Dysphagia is the presenting symptom in the majority of patients (65%), initially to solid food and then progressively to liquids. Some patients compensate for retrosternal fullness with deliberately slow swallowing.

Regurgitation of undigested food, which may also result in nocturnal coughing and pulmonary complications.

Chest pain and heartburn.

Weight loss in advanced disease.

Patients with achalasia have an increased risk (5%) of developing squamous cell carcinoma in the mid-oesophagus (with a mean 20-year interval between the onset of dysphagia and the malignant change).

9

What are the investigative findings of a patient with achalasia?

Chest radiograph (CXR) (Figure 3) – which may demonstrate a mega-oesophagus with an air-fluid level in the posterior mediastinum and aspiration pneumonitis.

Barium swallow (Figure 4) – which has a sensitivity of 75% and may demonstrate:

a)

narrow tapering (‘bird’s beak’ appearance) in the distal oesophagus;

b)

dilation of the proximal oesophagus;

c)

absence of peristalsis;

d)

poor oesophageal emptying.

Oesophagogastroduodenoscopy (OGD) – which is usually normal in patients with achalasia but should be performed to rule out distal oesophageal carcinoma. The endoscope should pass normally through the LOS without resistance.

Oesophageal manometry (Figure 5) – which is the gold standard for the diagnosis with characteristic features including:

a)

absence of peristalsis;

b)

weak simultaneous contractions, which may be present in the body of the oesophagus;

c)

incomplete relaxation of the LOS (<50% of baseline pressure) with high resting LOS pressure (>26mmHg).

10

What are the principles of managing a patient with achalasia?

Relieving the functional obstruction by relaxing the LOS.

Symptom control.

Prevention of the complications of achalasia.

The therapeutic options include:

a)

pharmacological therapy – using sublingual nitrates, calcium channel blockers, phosphodiesterase inhibitors and anticholinergic agents;

b)

endoscopic therapies:

i)

balloon dilation of the LOS;

ii)

botulinum toxin injection into the LOS;

c)

surgical myotomy.

Long-term medication has limited utility and is reserved for patients with debilitating comorbidities.

11

What are the principles of endoscopic balloon dilation in a patient with achalasia (Figure 6)?

A 30-50mm pneumatic balloon is fluoroscopically positioned and inflated to stretch the LOS forcibly enough to allow oesophageal emptying but not to cause oesophageal perforation or gastro-oesophageal reflux.

At 2 years, there is an 80% success rate when the LOS pressure is reduced to <10mmHg after dilation.

Endoscopic balloon dilation is usually an effective treatment in older patients, as compared to younger patients where the response is often poor.

Repeat dilation is required in approximately 20% of patients, with the effectiveness reducing with each repeat dilation.

Complications include perforation (1-3%), with a low mortality risk (0.3%).