From Volume 41, Issue 5, June 2014 | Pages 413-422
Dysphagia is defined as a ‘difficulty in swallowing’ and is commonly found in the general population, particularly in the elderly. This article gives an overview of the more frequently encountered swallowing disorders and provides advice on how to manage the dysphagic patient in the dental surgery.
Dysphagia is a medical term defined as a ‘difficulty in swallowing’ and can include saliva, liquids and foods of all consistencies.1 It derives from the Greek root dys meaning difficulty or disordered, and phagia meaning ‘to eat’. It describes difficulties in the oral preparation of food for swallowing or moving the bolus from the mouth to the stomach so may include difficulties in positioning of food in the mouth and oral movements. Dysphagia is distinguished from similar symptoms including odynophagia, which is defined as painful swallowing, and globus, which is the sensation of a lump in the throat.
Swallowing is a process by which food and liquid move from the mouth, down through the back of the throat, through the oesophagus and into the stomach. It is estimated that each individual swallows between 500 and 2000 times per day and it occurs during sleep and in utero.
Swallowing has been divided into three phases, which are defined by the position of the bolus at any one time:
In this phase, food is reduced to a bolus, chewed, mixed with saliva and then transported from the anterior to posterior oral cavity for passage into the pharynx.
This phase is characterized by involuntary acts and the activation of mechanisms which trigger peristaltic reflexes.2
The velopharyngeal opening completely closes, the hyoid and larynx ascend superiorly and the epiglottis downfolds. The tongue base makes contact with the pharyngeal wall to form a seal, then the top and bottom pharyngeal muscles start to contract. The hyoid-laryngeal complex continues to move superiorly and the laryngeal inlet closes. The epiglottis completely folds down to an inverted position and the vocal cords adduct. The cricopharyngeus muscle then relaxes and the upper oesophageal inlet opens.3 During the pharyngeal phase, which occurs rapidly, apnoea occurs to prevent food entering the airway.
The upper oesophageal sphincter opens and peristalsis carries the bolus through the oesophagus to the stomach. As the bolus reaches the stomach, the lower oesophageal sphincter opens. The oesophageal phase is much slower and may take 10-12 seconds.4
The reader is referred to a series of articles by Cadden and Orchardson in Dental Update for a more comprehensive description of the mechanisms of swallowing.5,6
It is believed that dysphagia is under-diagnosed; in 2007–2008 there were 22,510 patients admitted to hospitals in England and Wales with a primary diagnosis of dysphagia and its incidence increases with advancing age. One report suggests that 70–90% of older people have some degree of swallowing dysfunction.7 The increase in incidence may be due to conditions including cerebrovascular accidents (CVAs), Parkinson's disease or merely as a result of the ageing process, which is thought to influence all phases of swallowing negatively.8 One study found 40–60% of nursing home residents were found to have a diagnosis of dysphagia.9 It has been reported that 23–50% of individuals who sustain a CVA will develop dysphagia following the brain injury which may be permanent or temporary.10,11
People with learning disabilities have cognitive and physiological impairments which may result in dysphagia and a large proportion suffer from dysphagia.12 In 2004, the National Patient Safety Agency (NPSA) published a report ‘Understanding the patient safety issues for people with learning disabilities’13 which highlighted the risks of dysphagia. In the four years since the report was published, awareness of dysphagia has increased and the NPSA has received 605 reports of choking-related incidents involving adults with learning disabilities.14
Dysphagia may be described by its location:15
Dysphagia can be secondary to defects in any stage of the swallowing process so there are numerous causes. It is helpful to distinguish between the causes of oropharyngeal and oesophageal dysphagia.
In younger patients, dysphagia is most commonly caused by muscular disease, webs and rings. The most frequent causes of dysphagia in elderly patients are CVAs, Parkinson's disease and dementia (Table 1).
| Mechanical and Obstructive Causes |
| Traumatic injuries to the head or neck |
| Infections, eg dental abscess, tonsillitis, tuberculosis |
| Lymphadenopathy |
| Zenker's diverticulum (pharyngeal pouch) |
| Reduced muscle compliance (myositis, fibrosis) |
| Thyromegaly |
| Head and neck malignancies |
| Cervical osteophytes |
| Neuromuscular Causes |
| Central nervous system diseases, eg Parkinson's, CVAs, Dementia, Cerebral palsy, Amytrophic lateral sclerosis, Huntingdon's chorea, Multiple sclerosis |
| Contractile disturbances, eg Myaestheis gravis, Muscular dystrophy |
| Other Causes |
| Poor dentition |
| Xerostomia |
| Dry mouth |
The causes of oesophageal dysphagia may be divided into diseases causing narrowing of the lumen of the oesophagus, diseases which are caused by a physical obstruction to the oesophagus by lymph node enlargement or direct invasion, or diseases affecting the oesophageal smooth muscle or sphincters that interrupt the peristaltic wave (Table 2).
| Diseases Causing Internal Narrowing of the Lumen of the Oesophagus |
| Oesophageal tumours |
| Peptic strictures |
| Oesophageal webs and rings, eg Plummer Vinson syndrome |
| Chemical injury |
| Post-radiation therapy |
| Infectious/eosinophilic oesophagitis |
| Diseases Causing External Narrowing of the Lumen of the Oesophagus |
| Tumours, eg lymphomas/lung tumours |
| Infections, eg Tuberculosis |
| Cardiovascular, eg aortic aneurysm |
| Diseases Affecting Smooth Muscle |
| Achalasia |
| Scleroderma |
Many medications can cause dysphagia. They can be divided into:
Swallowing assessment may be divided into clinical examination and examination using instrumentation. Clinical examination can be carried out by clinicians, speech and language therapists or nurses in a hospital setting. The patient is presented with a small amount of food or water and the assessor watches for signs of dysphagia and aspiration. The signs include leakage of water from the mouth, facial weakness, poor muscular co-ordination, delayed pharyngeal/laryngeal elevation, choking, breathlessness and changes in voice quality after swallowing.16
The ‘gold-standard’ for swallowing assessment is videofluoroscopy (VFS),17 also known as the modified barium swallow. Radio-opaque barium liquid of varying consistencies is swallowed by the patient and moving images of the swallowing process are captured. The ‘swallow’ is recorded and can be played back at varying speeds to show the passage of the radio-opaque material through the oral cavity, pharynx and oesophagus. The motion picture produced will illustrate whether any of the barium has entered the airway. This procedure takes approximately 15 minutes and is available at most hospitals. It is carried out by speech therapists, radiographers and radiologists.
This examination has been developed over the last 20 years and has the advantage over VFS in that it does not expose the patient to radiation. It is carried out at the bedside and involves the insertion of a nasoendoscope to the level of the soft palate to give a view of the hypopharynx and larynx when the patient is eating. It requires a highly skilled operator and technical equipment.
Dynamics magnetic resonance imaging, commonly referred to as Cine MRI, is a new technique that has been used to visualize the dynamic structures of the oral cavity during swallowing.
Cine MRI directly visualizes the dynamics of swallowing of patients with oral and oropharyngeal cancer and has been shown to yield additional information compared to standard examination of swallowing. It is not intended to replace other swallowing evaluation techniques but is considered as a useful adjunct, showing particular tongue muscles, the floor of the mouth, tongue mobility and the extent and location of the tumour.18
Two scales have been described which are used to reflect the oral intake of patients with dysphagia:
This scale was developed to assess the oral intake of food and liquid in dysphagic patients who had suffered CVAs. It describes the functional level of the patient's actual daily oral intake of food or liquid.19 Patients are assigned a level of 1–7 relating to their degree of oral feeding. Levels 1–3 relate to varying degrees of non-oral feeding; levels 4–7 relate to varying degrees of oral feeding with non-oral supplementation (Table 3).
| Tube Dependent (Levels 1–3) | |
| Level | Oral intake |
| 1 | No oral intake |
| 2 | Tube dependent with minimal/inconsistent oral intake |
| 3 | Tube supplements with consistent oral intake |
| Total Oral Intake (Levels 4–7) | |
| Level | Oral intake |
| 4 | Total oral intake of a single consistency |
| 5 | Total oral intake of multiple consistencies requiring special preparation |
| 6 | Total oral intake with no special preparation, but must avoid specific food or liquid items |
| 7 | Total oral intake with no restrictions |
To score the functional oral intake using this scale, information is obtained from various sources including medical charts, dietary journals and patient/carer reporting. This scale is useful for documenting changes in oral feeding function following a CVA.
The food intake level scale is a scale described in 2012. It comprises a 10 point observer-rating scale to describe the severity of dysphagia20 (Table 4). Although the scale shows similarities to the FOIS, it is believed to be more sensitive to changes in the oral intake of food than the FOIS as it has 10 items rather than 7.
| No Oral Intake | |
| Level 1 | No swallowing training is performed except for oral care. |
| Level 2 | Swallowing training not using food is performed. |
| Level 3 | Swallowing training using a small quantity of food is performed. |
| Oral Intake and Alternative Nutrition | |
| Level 4 | Easy to swallow food less than the quantity of a meal (enjoyment level) is ingested orally. |
| Level 5 | Easy to swallow food is orally ingested in one or two meals, but alternative nutrition is used as a complement. |
| Level 6 | The patient is supported primarily by ingestion of easy to swallow food in three meals, but alternative nutrition is used as a complement. |
| Oral Intake Alone | |
| Level 7 | Easy to swallow food is orally ingested in three meals. No alternative nutrition is given. |
| Level 8 | The patient eats three meals by excluding food that is particularly difficult to swallow. |
| Level 9 | There is no dietary restriction, and the patient ingests three meals orally, but medical considerations are given. |
| Level 10 | There is no dietary restriction, and the patient ingests three meals orally (normal). |
Choking may occur during the normal process of swallowing. Choking occurs when the passage of air to the lungs is blocked by a foreign body and is a precursor to asphyxiation. Signs of choking include coughing, gagging, the inability to speak, breathe or cry, loss of consciousness and cyanosis.21 If the obstruction is not successfully removed, then asphyxiation and ultimately death may result.
Swallowing problems may lead to inhalation of either the oropharyngeal or gastric contents into the airway. If the oropharyngeal or gastric contents enter the lower respiratory tract or larynx (below the true vocal cords), then aspiration is said to have occurred.13 People without swallowing abnormalities routinely aspirate microscopic amounts of food and liquid but gross aspiration is abnormal and can lead to respiratory complications.
In addition to the syndromes listed above, dysphagia may lead to malnutrition, dehydration and a poor quality of life. Chadwick et al reviewed dysphagia in people with learning disabilities and stated that aspiration frequently leads to chest infections which are the leading cause of death in this group.13
Sialorrhoea (drooling) is described as the unintentional loss of saliva from the mouth and is frequently seen in patients with dysphagia. It is thought to be due to a tendency to swallow less frequently and weakness of the orofacial musculature rather than the production of excessive saliva. It is worsened by poor posture, impaired head control and excitability.
Sialorrhoea frequently leads to the development of dry, sore, inflamed skin in the mouth, chin and neck region, which may lead to infection. Dehydration may occur owing to the loss of fluid and eating may become difficult.
Interventions for treating dysphagia are often administered by speech and language therapists (SLTs). Basic interventions involve the modification of fluid and food consistencies, postural techniques, swallowing exercises, and stimulation of oral and pharyngeal structures. Local stimulation techniques include thermal and electrical stimulation. Transcranial direct current stimulation (TDCS) and transcranial magnetic stimulation (TMS) are also under investigation. Acupuncture techniques are used routinely in some countries and show some success.
A number of types of pharmacological agents (capsaicin, black pepper oil, cabergoline, angiotensin-converting enzyme (ACE) inhibitors, and nifedipine) have also been studied in patients, mostly with chronic dysphagia, but their effects are questionable.22
The nutritional intake of patients with dysphagia may be managed by using modified diet consistencies or tube feedings if swallowing is severely impaired. For the latter, tube feedings can be inserted into the nose and positioned in the stomach (nasogastric tube (NGT)), jejunum (nasojejunal tube (NJT)) or surgically placed in the stomach (percutaneous endoscopic gastrostomy (PEG)), radiologically inserted gastrostomy (RIG) tube feeding, or parenteral (intravenous (iv)) feeding.
Insertion of an NGT is relatively easy and readily reversed, but still carries significant risks, which have been highlighted by safety alerts from the UK National Patient Safety Agency.23 PEG insertion is an invasive procedure and can be complicated by bleeding, local infection, peritonitis, perforation, and aspiration leading to pneumonia and increased mortality in older stroke patients. PEG is more acceptable to patients and is more effective in the delivery of feed and maintaining nutritional status in long-term dysphagic patients, however, its insertion requires an invasive procedure carried out under general anaesthesia.
The dental team treating someone with dysphagia should be aware of the problems that may present:
The major concern when treating patients with dysphagia is the risk of aspiration during dental treatment which may lead to choking or aspiration pneumonia. In order to avoid this:
In addition to the dental management of the patient with dysphagia, the dental team should be aware of other problems that commonly arise in the dysphagic patient. These are:
Many attempts have been made to manage sialorrhoea and have met with varying success rates. Input may be required from speech and language therapists and occupational therapists (who work with patients to improve their swallowing mechanics and support their posture with devices such as the head-back wheelchair). Ear nose and throat surgeons may be required to identify and correct causes of airway obstruction which contribute to drooling and neurologists may assess the patient for particular neuropathies.
After a thorough assessment, treatments are usually offered in a stepwise fashion from non-invasive, non-surgical therapies to most invasive:
Transtympanic neurectomy is a process of denervation of the salivary glands. It is carried out through the middle ear where the chorda tympani and tympanic plexus pass through en route to the salivary glands. The procedure is quick and easy to perform under local anaesthesia. Salivary function returns within 6–18 months as the nerve fibres regenerate.
Submandibular duct relocation distally within the oral cavity may be performed or the submandibular gland(s) may be excised. Parotid ducts may be relocated or ligated.
The following instructions should be given to the carer/patient:
These are recommended for patients in nursing homes where suction is readily available. There are several examples on the market, such as the ‘Plak-vac’ (Trademark Medical, St Louis, Missouri) which is a re-usable combination yankauer sucker and toothbrush. It can be used with wall suction onwards or with portable suction pumps. The ‘Vac-U-Brush’ (PR Medical, Steamboat Springs, Colorado) is another alternative which is designed for use with portable suction units (Figure 2).
Single use suction toothbrushes called ‘Toothettes’ (Sage Products, Cary, Illinois) which attach to standard suction lines are available and commonly used in North America.
Kimberley Clark has developed an oral care system largely for use with the ventilated critically ill patient to reduce the incidence of ventilator associated pneumonia. Their system is called ‘KimVent VAP Solutions’ and consists of a variety of suction toothbrushes, swabs and suction catheters which may be interchanged, depending on which component is most suitable for individual patients.
Dentists will frequently see patients with dysphagia in their practice. Careful assessment is required but the majority of patients can receive dental treatment in a primary care setting with some modifications.
