Approach Considerations
History and physical examination alone may not be adequate to make a diagnosis in cases of silent aspiration. Further diagnostic tests, such as the following, should be performed as needed:
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Transnasal esophagoscopy: Especially useful in cases of esophageal diverticula or tumor [41]
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Cervical auscultation: Permits the clinician to assess pharyngeal swallow by listening to stereotypical sounds through a stethoscope; cervical auscultation may be a useful bedside tool, especially in the absence of other diagnostic tools
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Blood tests: Including thyroid-stimulating hormone, vitamin B-12, and creatine kinase; may be useful, especially in neurogenic dysphagia
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Imaging studies: May include videofluoroscopy, CT scanning, MRI, chest radiography
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Endoscopic examination
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Esophageal pH monitoring: The criterion standard for diagnosing reflux disease; a nasogastric probe is inserted into the patient's esophagus to record pH levels, and these are compared with the patient's record of symptoms over 24 hours to determine whether acid reflux contributes to the patient’s symptoms
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Pulmonary function tests
The above list of tests is not exhaustive, and further tests may be required if there is a need to follow up on other associated findings during the initial evaluation. Consultations with and further evaluations by an ear, nose, and throat (ENT) surgeon and a speech-language therapist also may be necessary.
Imaging Studies
Chest radiography
Chest radiography is a simple assessment for pneumonia. The image below shows aspiration of liquid barium into the distal bronchus.
Delayed posteroanterior chest image shows aspiration of liquid barium into the distal bronchus.
Ultrasonography
Ultrasonography is used to evaluate soft-tissue dynamics during the oral and pharyngeal phases of swallowing, looking at tongue function and laryngeal/hyoid elevation. Ultrasonography is useful in diagnosing childhood tongue incoordination and could be combined with fiberoptic endoscopic examination of swallowing (FEES) to diagnose extramural and submucosal lesions that FEES alone may not detect.
CT scanning and MRI
CT scanning and MRI provide excellent definition of structural abnormalities, particularly when they are used to evaluate patients with suspected CNS causes of dysphagia.
Videofluoroscopy
Videofluoroscopy is designed to study the anatomy and physiology of the oral, pharyngeal, and esophageal stages of deglutition. It is considered the standard for identifying patients who have the potential to develop pneumonia and for diagnosing aspiration and swallowing problems. [42] It is also used in determining dietary and compensatory strategies. (The terms videofluoroscopic swallowing study [VFSS] and modified barium swallow [MBS] often are used interchangeably.) [43]
Although some clinical researchers believe that it is possible to identify patients with the potential to develop pneumonia by interpreting findings of bedside tests, most agree that discrepancies exist between findings of bedside tests and videofluoroscopy. [44]
Splaingard and colleagues reported that only 42% of patients who had aspiration on videofluoroscopy were diagnosed as aspirators by speech/language pathologists conducting bedside evaluations. [42] This finding indicated that bedside results are not sufficient for evaluating the frequency of aspiration. In general, 40-70% of patients have silent aspiration, which does not manifest specific symptoms.
If a patient undergoing a VFSS aspirates or if he/she retains food after swallowing, the next step is to evaluate the quantity of retained food, the mechanism of retention or aspiration, and the patient's response. In general, various food consistencies, volumes, postural techniques, and swallowing maneuvers to enhance swallowing efficiency or safety are tested during the study, and clinical decisions (eg, changing food viscosity, finding appropriate swallowing postures or maneuvers) are made.
This study is expensive because of the special expertise, equipment, and facilities required. (See the images below of videofluoroscopic swallowing findings.)
Lateral projection of the videoprint of a videographic swallowing study shows the epiglottis (E), pyriform sinuses (P), tongue (Tg), trachea (Tr), and vallecula (V).
Lateral projection of the videoprint of a videographic swallowing study shows residues on the vallecula (Vr) and pyriform sinuses (Pr) and a small amount of aspirated liquid barium in the trachea (As).
Anterior projection of the videoprint of a videographic swallowing study shows residues on the vallecula (Vr) and pyriform sinuses (Pr).
Lateral projection of the videoprint of a videographic swallowing study shows supraglottic penetration.
Lateral projection of the videoprint of a videographic swallowing study shows subglottic aspiration.
Scintigraphy
Scintigraphy has limited value in evaluating pharyngeal swallowing disorders. This test is useful in quantitative and qualitative evaluation of subglottic aspiration, esophageal motility disorders, and gastroesophageal reflux. [45]
Oropharyngeal transit time can be measured through time-activity curves constructed from a specific region of interest (ROI) of the mouth, pharynx, and esophagus. Peaks and nadirs of the first derivative curve correspond to peak emptying or filling rates of the respective regions.
Scintigraphic examination of dysphagia entails having the patient swallow a technetium-99m (99m Tc) sulfur colloid bolus in order to label oral secretions. Neck and chest imaging is subsequently performed to detect aspirations.
Endoscopy
FEES
An FEES is used to evaluate any structural abnormalities in the nasopharynx, laryngopharynx, and hypopharynx and is particularly useful when a VFSS is not feasible (eg, in critically ill patients unable to tolerate any risk of aspiration, patients in intensive care units who cannot be transferred to the fluoroscopy room, or patients who require prompt evaluation). [43]
The FEES uses a transnasal laryngoscope, and swallowing is directly evaluated by using measured quantities of food colored with blue liquid dye. It is a sensitive technique for detecting premature bolus loss, laryngeal penetration, tracheal aspiration, and pharyngeal residue. Because pharyngeal contraction obstructs the lumen, the FEES does not demonstrate the motion of essential food pathway structures or show the food bolus during the swallow.
Gastroesophageal endoscopy
Gastroesophageal endoscopy enables the best assessment of the esophageal mucosa. Endoscopy has the added benefits of permitting the detection of infection and erosions and of enabling biopsy.
Reflex Cough Test
For the reflex cough test, a 20% solution of L-tartaric acid is dissolved in 2 mL of sterile normal saline. Using a nasal nebulizer, the patient inhales the solution, which stimulates cough receptors in the vestibule of the larynx and initiates the laryngeal cough reflex.
The laryngeal cough reflex protects the laryngeal aditus from significant aspiration and reduces the risk of respiratory complications (eg, pneumonia). An impaired laryngeal cough reflex may permit laryngeal penetration and increase the risk of aspiration pneumonia. An acute cerebrovascular accident often appears to affect the protective cough reflex.
Using a reflex cough test, Addington and colleagues were able to identify which patients with stroke were unlikely to subsequently develop aspiration pneumonia (specificity, 100%). [46]
Electromyography
Electromyography (EMG) is of limited use clinically. It is employed mainly in research to evaluate individual myoelectric function.
Swallowing electromyography
Mechanical upward-downward movement of the larynx is detected by using a piezoelectric sensor while submental integrated EMG activity is recorded during dry and wet swallowing. EMG activity of the cricopharyngeal muscle of the upper esophageal sphincter also can be recorded. [47]
In patients with muscular disorders, laryngeal elevators are involved, whereas the cricopharyngeal sphincter is intact. In patients with clinical signs of involvement of the corticobulbar fiber (eg, patients with ALS and pseudobulbar palsy), discoordination between paretic laryngeal elevators and the hyperreflexic cricopharyngeal sphincter is present.
EMG can be used for muscle selection and for performing injections of botulinum toxin in patients with dysphagia caused by cricopharyngeal muscle spasm or hypertonicity.
Laryngeal electromyography
Laryngeal EMG can help the clinician to diagnose oropharyngeal dysphagia of peripheral nerve origin (eg, from recurrent laryngeal or superior laryngeal nerve injury).
Manometry
Manometry is performed to assess motor function of the esophagus. A catheter with several electronic pressure probes is passed into the stomach to measure esophageal contractions and to define upper and lower esophageal responses to swallowing. Manometry reveals definitive abnormalities in only 25% of patients with nonobstructive lesions; therefore, its clinical use in oropharyngeal dysphagia is limited.
Manometric fluoroscopy consists of manometry combined with VFSS. It is used to check the pressure gradient of the pharynx and the pharyngoesophageal junction.
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Lateral projection of the videoprint of a videographic swallowing study shows the epiglottis (E), pyriform sinuses (P), tongue (Tg), trachea (Tr), and vallecula (V).
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Lateral projection of the videoprint of a videographic swallowing study shows residues on the vallecula (Vr) and pyriform sinuses (Pr) and a small amount of aspirated liquid barium in the trachea (As).
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Anterior projection of the videoprint of a videographic swallowing study shows residues on the vallecula (Vr) and pyriform sinuses (Pr).
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Lateral projection of the videoprint of a videographic swallowing study shows supraglottic penetration.
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Lateral projection of the videoprint of a videographic swallowing study shows subglottic aspiration.
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Delayed posteroanterior chest image shows aspiration of liquid barium into the distal bronchus.
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Oroesophageal tube feeding can be used by patients who decline to be enterally fed through a nasogastric or gastrostomy tube.
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Oral preparatory phase of normal swallowing.
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Oral propulsive phase of normal swallowing.
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Pharyngeal phase of normal swallowing.
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Esophageal phase of normal swallowing.
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- Overview
- Presentation
- DDx
- Workup
- Treatment
- Approach Considerations
- Pharmacologic Treatment
- Dietary Modification
- Hydration
- Oral Hygiene and Dental Care
- Exercise
- Facilitation Techniques
- Compensatory Techniques
- Enteral Feeding
- Cricopharyngeal Myotomy
- Other Maneuvers and Techniques
- Surgery for Chronic Aspiration
- Treatment of Tracheostomy-Associated Dysphagia
- Evaluating Recovery From Dysphagia
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