Medical Speech Pathology

Curiosity, Dialogue, and Knowledge

Introduction to Dysphagia


Dysphagia

Introduction

Dysphagia involves impaired execution of the oral, pharyngeal, or esophageal stages of swallowing. This may include problems chewing the food, preparing the bolus, initiating the swallow, propelling the bolus through the pharynx, or passing the food through the esophagus.

There are many causes of dysphagia:

Strokes (most common) especially brain stem and anterior cortical strokes often result in poor motor control of swallowing structures

Oral and pharyngeal tumors

Various neurological diseases such as Parkinson’s disease, ALS, MS, Myasthenia Gravis, Muscular Dystrophy, or Dystonia

Surgical or radiation treatment of oral, pharyngeal, and laryngeal cancers

Traumatic brain injury or cervical spine disease

Cerebral palsy

COPD and other pulmonary diseases

Genetic factors- autonomic imbalance, sensory deficits or motor dyscoordination

Side effects of certain prescription drugs

 

Feeding Disorder vs. Swallowing Disorder

Feeding and swallowing are related but are different activities. Feeding is the transportation of food from the plate to the mouth and disorders may be due to motor impairments or severe cognitive impairments. On the other hand, swallowing is the transportation of food from the mouth to the stomach. Swallowing is divided into 4 phases, the oral preparatory phase, oral phase, pharyngeal phase, and esophageal phase.

 

The 4 Phases of Swallowing

Oral Preparatory Phase

This is when the food is placed in the mouth and is masticated. Food is formed into a rounded mass of food that is ready to be swallowed called a bolus. Structures which assist this process include the lips, cheeks, tongue, teeth, and jaw.

 

Disorders of the Oral Preparatory Phase Include:

Problems chewing food because of reduced range of lateral and vertical tongue movement

Reduced range of lateral mandibular movement

Reduced buccal tension

Poor alignment of the mandible and maxilla

Difficulty forming and holding the bolus

Abnormal holding of the bolus

Slippage of food into the anterior and lateral sulci

Aspiration before the swallow due mostly to weak lip closure and lack of bolus control

Reduced tongue movement and inadequate tongue and buccal tension

 

Oral Phase

This phase begins with the anterior-to-posterior tongue action that moves the bolus posteriorly. The phase ends as the bolus passes through the anterior faucial arches when the swallow reflex is initiated.

 

Disorders of the Oral Phase Include:

Anterior, instead of posterior, tongue movement and generally weak tongue movement

Reduced range of tongue movement and elevation

Reduced labial, buccal, and tongue tension and strength

Food residue in various places suggesting an incomplete swallow

Premature swallow of bolus and aspiration before swallow

 

Pharyngeal Phase

This phase consists of the dual voluntary and reflexive actions of the swallow. Reflexes are triggered by the contact the food makes with the anterior faucial pillars. The pharyngeal phase involves velopharyngeal closure, laryngeal closure by the superior and anterior motion of the elevated larynx which causes the epiglottis to fold over the airway, reflexive relaxation of the cricopharyngeal muscle for the bolus to enter, and reflexive contractions of the pharyngeal constrictors to move the bolus down. (While this phase is primarily reflexive, there is volitional control of the movements of the larynx).

 

Disorders of the Pharyngeal Phase Include:

Difficulties in propelling the bolus through the pharynx and into the pharyngoesophageal sphincter (PES) segment

Delayed or absent swallowing reflex

Nasal regurgitation of the bolus due to mistiming of the velum or velar weakness/insufficiency

Food coating on the pharyngeal walls, food residue in valleculae, on top of airway, in the pyriform sinuses, and throughout the pharynx that can be subsequently aspirated into the lungs (residue is a symptom the cause of which can be multifactorial)

Reduced pharyngeal peristalsis (the constricting and relaxing movements of the pharynx) and pharyngeal paralysis/paresis (usually unilateral from stroke)

Inadequate closure of the airway leading to aspiration during or after swallow

Reduced movement of the base of the tongue

Reduced laryngeal movement

Cricopharyngeal dysfunction

 

Esophageal Phase

This phase is not under voluntary control. It begins when the bolus arrives at the orifice of the esophagus. The bolus is propelled through the esophagus by peristaltic action and gravity into the stomach. Bolus entry into the esophagus results in restored breathing and a depressed larynx and soft palate.

 

Disorders of the Esophageal Phase Include:

Difficulty passing the bolus through the cricopharyngeus muscle and past the seventh cervical vertebra

Backflow of food from esophagus to pharynx

Reduced esophageal contractions

Formation of a diverticulum (a pocket which collects food)

Development of a tracheoesophageal fistula (a hole between the trachea and the esophagus)

Esophageal obstruction (e.g. a tumor, or foreign body)

N.B.- If this is your first exposure to this material, the ability to see the anatomy in motion via a Modified Barium Swallow Study or through a Fiberoptic Endoscopic Evaluation of Swallowing will be highly beneficial; so, I am putting a link here to both of these types of studies.  Enjoy!

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