Dysphagia

Overview of dysphagia

Incidences of strokes, cardiovascular disorders or neurological disorders give rise to a myriad of systemic disorders that may have long-lasting impacts. In the majority of the cases, musculoskeletal disorders are the inevitable outcomes of these diseases. They usually affect elders and children, men and women alike.

Dysphagia is one such disease that is marked by a difficulty in swallowing. A population-based study conducted by the International Association of Logopedics and Phoniatrics has shown that the global prevalence rate of dysphagia is 13.5%. They have also estimated that around 29-64% of the stroke patients are likely to suffer from dysphagia. Studies also show that 24-34% people having multiple sclerosis and 81% people with Parkinson’s disease have a tendency to develop dysphagia. Clearly, the current global burden is alarming and needs to be addressed.

What is dysphagia?

The term “dysphagia” is derived from two Greek words- “dys” meaning bad or disordered and “phag” meaning eating. In medical terms, dysphagia is a condition where a person experiences difficulties in swallowing. This condition mainly arises due to obstruction of the oropharyngeal or oesophageal passage during eating or swallowing. There are instances where the patient cannot control the content of food or saliva inside the mouth. Some patients may not be able to consume food at all, while some others may have trouble swallowing liquids and certain foods safely. Persistent dysphagia may lead to nutritional deficiencies and other illnesses. 

What are the different stages of swallowing?

The swallowing of food and liquids is divided into three distinct stages-

Oral stage: This is the very first phase where the food enters the buccal cavity and undergoes mastication. Bolus formation occurs in this phase.

Oropharyngeal phase: The following processes occur in order-

• The soft palate is raised and the nasopharynx is closed
• Larynx and the hyoid bones move in the upward direction
• The epiglottis moves backward and closes
• Relaxation and opening of the upper oesophageal sphincter occurs
• The tongue now pushes the bolus into the esophagus
• Contraction of pharynx occurs
• The upper sphincter shuts
• The larynx opens again

Oesophageal phase: This is the third and the final stage in the food ingestion process. It encompasses the following sub-stages-

• Sequential contraction of the esophagus
• Relaxation of the lower oesophageal sphincter muscles
• Transfer of the bolus to the stomach

Abnormalities in any of the above processes may lead to some major problems in swallowing.

What are the different types of dysphagia?

Dysphagia has two main categories namely- oropharyngeal and oesophageal dysphagia. Both the types will be discussed in separate sections.

Oropharyngeal dysphagia

It occurs due to problems in the oropharyngeal muscles and is also known as “high” dysphagia. In younger people, this type occurs due to dysfunctions of the muscles, nerves and the structures of the oral cavity, upper oesophageal sphincter, and the pharynx. In the elder patients, this condition is triggered by problems of the central nervous system like stroke, Parkinson’s disease, and dementia.

What are the main causes of Oropharyngeal dysphagia?

The factors that induce Oropharyngeal dysphagia can be classified into two categories-

Mechanical causes: 

• Infections like retropharyngeal abscess
• Enlarged thyroid gland
• Lymphadenopathy
• Zenker diverticulum
• Muscular problems (Eg: Myositis, Fibrosis)
• Eosinophilic esophagitis
• Malignancies in the head and neck
• Hard fibrotic strictures
• Oropharyngeal malignancies and neoplasms
• Cervical osteophytes

Neuromuscular causes: 

• Diseases of the central nervous system such as Parkinson’s disease, cerebral palsy, bulbar palsy, stroke, amyotrophic lateral sclerosis and cranial nerve palsy
• Contractile dysfunctions like oculopharyngeal muscular dystrophy, myasthenia gravis and a few others

What are the clinical manifestations of Oropharyngeal dysphagia?

The main clinical symptoms of Oropharyngeal dysphagia are as follows-

• Problems starting the process of swallowing
• Difficulties in repetitive swallowing
• Nasal regurgitation
• Constant coughing and drooling
• Speaking in a nasal tone
• Loss of cough reflex
• Choking
• Diplopia (double vision)
• Problems in speech (dysarthria)
• Bad breath or halitosis (present in Zenker’s diverticulum)
• Recurrent pneumonia

Oesophageal dysphagia

In this type, the problems in swallowing arise from the main body of the oesophagus, lower oesophageal sphincter or the cardia of the stomach.

Under what conditions may oesophageal dysphagia arise?

Following are the conditions that precipitate oesophageal dysphagia-

Intraluminal factors: Acute dysphagia may occur in this case due to the presence of foreign particles.

Mediastinal diseases: These diseases cause oesophageal constriction. Three main complications seen in this case are-

• Tumours (Eg: Lymphoma)
• Infections (Eg: Tuberculosis)
• Cardiovascular conditions (Eg: vascular compression)

Mucosal diseases: Narrowing of the lumen occurs due to fibrosis, inflammation or neoplasia. The conditions commonly observed in this case are-

• Peptic contraction
• Oesophageal rings and webs
• Oesophageal tumours
• Chemical or radiation injury
• Infectious or eosinophilic oesophagitis
• Tumour or granulous overgrowth

Neuromuscular diseases: It affects the oesophageal smooth muscles. The common complications are-

• Oesophageal spasms
• Connective tissue disorders

What are the main symptoms of oesophageal dysphagia?

The main clinical manifestations of oesophageal dysphagia are given below-

• Peptic constriction
• Oesophageal neoplasia
• Esophageal webs and rings
• Scleroderma
• Spastic motility disorders
• Esophageal motility disorders
• Functional dysphagia

Diagnosis ,treatment, & prevention 

The major diagnostic tests the doctors prescribe for dysphagia are as follows-

• Video fluoroscopy
• Upper endoscopy
• Fiberoptic endoscopic evaluation of swallowing (FEES)
• Pharyngoesophageal high-resolution manometry
• Automated impedance manometry
• Water swallow test
• Transnasal oesophagoscopy
• pH monitoring

Nasogastric and endoscopic tubes are often used for the treatment of dysphagia.

After the evaluation by a speech-language pathologist, the treatment plan can be formulated depending on the underlying cause and type of dysphagia. Based on the type of dysphagia, the following treatment can be done:

Oropharyngeal dysphagia

• Exercises- Certain exercises can be learned that help to regain the coordination between the swallowing muscles. This can stimulate the nerves which trigger the swallowing reflex and treat dysphagia.
• Positioning- A correction might be required in the way food is placed in the mouth, the position of the head and the body during swallowing. These changes can make the swallowing process easier.
• Swallowing techniques- In case of neurological problems such as Parkinson’s disease and Alzheimer’s disease, certain swallowing techniques and exercises can help in overcoming dysphagia.

Esophageal dysphagia

• Esophageal dilation- this is performed in case of esophageal stricture or the stiffness of the esophageal sphincter. This can be done by passing a balloon attached to an endoscope, which helps in expanding the width of the esophagus. Flexible tubes can be used to dilate or stretch the esophagus.
• Surgical intervention- in conditions such as achalasia, esophageal tumor or pharyngoesophageal diverticulum, a surgical correction might be required to make the esophagus patent. Some of the surgical procedures are laparoscopic Heller myotomy, esophageal dilation by means of an endoscope, and stent placement surgeries.
• Medications- In case of GERD (Gastro-Esophageal Reflux Disease), oral medications are prescribed to lessen the acid production in the stomach. Corticosteroids can be prescribed for eosinophilic esophagitis. Smooth muscle relaxants are recommended in case of esophageal spasm.

In cases of severe dysphagia, a liquid diet might be advised or the use of a feeding tube (in hospital settings) is recommended. This can help in preventing malnutrition and dehydration due to dysphagia.

Prevention is mainly by getting the underlying cause diagnosed and treated promptly. Regular health check-ups also help in early diagnosis of developing health conditions which might cause dysphagia in future. Any infection in the oral cavity or throat must be treated promptly. A balanced diet should be taken and substances causing acid reflux should be avoided.

1. http://swallowingdisorderfoundation.com/national-dysphagia-awareness-month-facts/
2. http://www.cdss.ca.gov/agedblinddisabled/res/VPTC2/9%20Food%20Nutrition%20and%20Preparation/Dysphagia_Fact_Sheet.pdf
3. https://jhu.pure.elsevier.com/en/publications/swallowing-disorders
4. https://www.healthline.com/health/difficulty-in-swallowing
5. https://www.mayoclinic.org/diseases-conditions/dysphagia/diagnosis-treatment/drc-20372033
6. https://www.asha.org/public/speech/swallowing/SwallowingAdults.htm