to determine if a patient’s swallowing and cough reflexes are appropriately intact to prevent a devastating aspiration event before oral feeding is resumed.
Accurate assessment of individuals with aspiration due to oropharyngeal dysphagia is critically important. Unrecognized dysphagia can lead to serious health consequences for patients, including dehydration, malnutrition, aspiration pneumonia, and even death. When a patient presents with complaints of dysphagia in the setting of a chronic cough, it is important to determine if those complaints are consistent with oropharyngeal or esophageal dysphagia and not presumed to be due to reflux disease. In this chapter, we will review assessment of oropharyngeal and esophageal swallowing in patients with chronic cough.
Patients with swallowing problems and chronic cough will often be treated at minimum by an otolaryngologist and a speech-language pathologist (SLP). Patients in the hospital with new-onset dysphagia will typically have a screening first to evaluate for swallow impairment (see the following bulleted list). Conversely, in the outpatient setting, patients find their way to either an SLP or an otolaryngologist, depending on referral patterns. The team approach to these complicated and medically ill patients is important for both diagnosis and intervention. Additional specialties that are often involved with the treatment of dysphagia with concomitant chronic cough include pulmonologists, gastroenterologists, and neurologists.
When a patient presents with chronic cough, dysphagia symptoms should be explored and pursued further if necessary. High-yield questions include:
■ Do you have any problem swallowing solid foods?
■ Do you experience choking or aspirating on liquids?
■ Are you losing weight?
■ Do you have to avoid any specific foods?
■ Have you ever received radiation treatment to the head and/or neck?
■ Do you have any history of respiratory infections, including pneumonia?
■ Do you have any history of head and neck surgery?
■ Do you ever regurgitate your food?
A positive response to any of these questions can suggest dysphagia that warrants workup to determine any contribution of dysphagia to the patient’s chronic cough. The otolaryngologist should always perform flexible laryngoscopy for the patient with chronic cough or dysphagia, as it will show anatomic changes that may explain the issues, such as a laryngeal mass, large glottic gap with or without vocal fold paralysis, or a large amount of pooling in the pyriform sinuses. If clinical suspicion is high, further testing is needed regardless of the findings on the first endoscopy.
The first step in making an accurate assessment of oropharyngeal dysphagia is screening. In the document “Preferred Practice Patterns for the Profession of Speech-Language Pathology,” the American Speech-Language-Hearing Association (ASHA) defines dysphagia screening as “a pass/fail procedure to identify individuals who require a comprehensive assessment of swallowing function or a referral for other professional and/or medical services.”4 Screening is typically performed by the SLP in the office or by other allied health care providers such as nurses in the hospital setting. The individual being screened is deemed to be either at risk or not at risk for oropharyngeal dysphagia.
Screening tools are meant to be quick and efficient, and to save time and money by identifying individuals who are at risk for dysphagia and aspiration and who may require further assessment. A screening allows the clinician to identify individuals who truly need a full, more expensive and time-consuming evaluation and prevents unnecessary utilization of these resources for individuals who do not.
Many approaches to screening have been suggested. Some suggest a screen should include a question-only approach. Although it was originally intended as an outcomes tool, there is evidence that the Eating Assessment Tool (EAT-10)5 can be used as a tool for predicting aspiration risk.6–8 Other approaches to screening include presentation of one or more boluses. What those boluses are and what bolus volumes are included differ. Many screenings incorporate water swallow tests,9–13 although bolus size varies among the different water screenings. Some utilize up to 10 small boluses of 3 to 5 mL of water,9, 14, 15 while others incorporate larger volumes of water of as much as 90 to 100 mL.10–13 A recent systemic review and meta-analysis of screening methods that incorporated a water swallow test revealed high specificity but low sensitivity for small bolus volumes, whereas water swallow tests incorporating consecutive sips of larger bolus volumes (90–100 mL) demonstrated higher sensitivity but lower specificity.16 In clinical practice and due to higher sensitivity, the large bolus screening appears to be a better screening tool through which people who actually have aspiration do not go undetected.
If a patient passes a valid, reliable, sensitive screen, a full swallowing evaluation, such as an instrumental assessment of swallowing (ie, modified barium swallow), is not needed and the patient is safe to begin receiving medications, liquids, and food without the need for further assessment. A failed screening indicates further assessment is needed. In the case of dysphagia, a patient who fails a valid and reliable screening should be referred to an SLP for further assessment.
CLINICAL SWALLOW EVALUATION
The clinical swallow evaluation (CSE) is often the next level of evaluation in the assessment of individuals at risk for oropharyngeal dysphagia. According to ASHA,17 the CSE allows the SLP to:
■ Integrate information from interview/case history, review medical records, and make observations from a physical exam
■ Observe and assess integrity and function of the structures in the upper airway and digestive tract
■ Identify the presence of and observe the characteristics of dysphagia based on clinical signs and symptoms
■ Identify clinical signs and symptoms of esophageal dysphagia or gastroesophageal reflux disease (GERD)
■ Determine the need for an instrumental exam (more objective assessment of swallow)
■ Determine if the patient is an appropriate candidate for treatment and/or management
■ Recommend an appropriate route of nutritional management
■ Recommend clinical interventions
Indications for a Clinical Swallow Evaluation
It is important for the SLP to understand what prompted the referral for a CSE and what the referring provider’s primary concern is regarding the patient. If a screening has been administered, failure results in referral for clinical or instrumental assessment. In other cases, the physician may refer directly to the SLP without the patient completing a prior screening. Referral for a CSE may be based upon the patient’s medical diagnosis or the patient’s nutritional status.
Often the patient’s complaints prompt the physician referral to an SLP for a CSE. Patients may complain of frequent coughing or choking during meals, feeling as if food or liquid gets stuck when they attempt to swallow, or prolonged meal times. They may also complain of pain associated with swallowing, odynophagia, or food or liquid coming out of their nose when they attempt to swallow. Any of these complaints may indicate an underlying swallowing problem and should result in referral for a CSE.
Components of the Clinical Swallow Evaluation
The first step in the evaluation is a thorough chart review. The chart review assists the clinician in formulating a hypothesis regarding the nature of the patient’s swallowing difficulty.
In the case of patients with chronic cough, it is particularly important to note any current or previous illnesses that correspond with onset of dysphagia symptoms, such as a recent upper respiratory infection. If the patient has a history of frequent upper respiratory illness, chronic aspiration should be considered as a possible cause. Presence of pneumonia or a history of pneumonia are highly predictive of aspiration risk.17 History of upper respiratory infection or respiratory failure necessitating intubation or tracheotomy should be noted. Repeated intubations or extubations, or traumatic intubations or extubations, can lead to laryngeal irritation or vocal fold motion impairment, with chronic cough occurring as a result of aspiration or penetration in the face of glottic incompetence. Additionally, clinicians should note whether the patient has a history of gastroesophageal reflux and if the patient is on medications to control reflux symptoms. Laryngopharyngeal reflux (LPR) can result in irritation to the larynx and hypopharynx and, more importantly, is postulated to cause protective upper esophageal sphincter hyperfunction that results in a feeling of difficulty swallowing. LPR is discussed in detail in Chapter 4.
Surgical history should also be reviewed. Specifically, previous surgery to the head and neck, including tracheostomy or surgical resection of head and neck cancer, should be noted. Surgeries can result in anatomical alterations that lead to changes in swallow physiology. Previous history of feeding tube placement may indicate a history of dysphagia or malnutrition.
The chart review should also include a review of current medications. Certain medications can adversely affect swallow function, either as a normal side effect of the drug or as a complication of the therapeutic action of the drug.31, 19 Medications that affect smooth or striated esophageal muscle function may cause dysphagia. Dysphagia resulting from a complication of the therapeutic action of a medication includes viral or fungal esophagitis in patients treated with immunosuppressive drugs or cancer therapeutic agents, or medications that can depress the central nervous system, such as benzodiazepines. Additionally, some medications such as nonsteroidal anti-inflammatory drugs (NSAIDS) can cause esophagitis, stricture formation, or esophageal ulceration with chronic use, leading to dysphagia symptoms.20 Other medications may cause xerostomia (dry mouth) and interfere with oral transit of the bolus, result in laryngeal irritation, particulate retention, and lead to chronic cough. Clinicians should also note if patients have been prescribed angiotensin-converting enzyme inhibitors (ACE inhibitors), as chronic cough may occur as a side effect in up to 10% of individuals taking these medications, and occurs more frequently in women than in men.21
The next step in clinical assessment is a thorough case history. The aim of the case history is to assist the clinician in formulating a hypothesis regarding the underlying pathophysiology causing the patient’s symptoms. The information gathered during the case history can be invaluable in determining the appropriate means of assessing swallowing function, for instance fluoroscopy or endoscopy, and in determining whether other professions, such as gastroenterology or neurology, should be consulted.
Common patient complaints include coughing, choking or strangling with food or liquids, food or liquids sticking in the throat, difficulty chewing, and prolonged mealtimes. In a patient with a history of chronic cough, it is particularly important to ask if coughing increases during or after eating or drinking. Increased coughing during eating can indicate penetration or aspiration of food or liquid; increased coughing after meals can indicate reflux, esophageal dysmotility, or a cervical diverticulum. Additionally, patient complaints of feeling as if food sticks, difficulty swallowing solid foods (often breads or steak), or difficulty swallowing liquids of extreme temperatures (either hot or cold) may indicate an esophageal phase issue rather than an oropharyngeal swallowing difficulty.22
History of Symptoms
Clinicians should also ask patients about the timeline of their dysphagia. Questions should include duration of dysphagia symptoms, whether the patient experienced any illnesses at the time dysphagia symptoms began, and if symptoms vary depending upon time of day. Patients reporting symptoms that are worse upon awakening and/or shortly thereafter may be experiencing gastroesophageal reflux, whereas those reporting a progression of their symptoms throughout the day or throughout the course of a meal may be experiencing muscle weakness or fatigue related to an underlying neurological condition. Changes in vocal quality that accompany the onset of the patient’s dysphagia can point to vocal fold pathology and warrant a closer look with laryngovideostroboscopy. For example, oropharyngeal sensation issues that lead to hypopharyngeal pooling and spill over into the larynx with a resultant “wet” sounding voice.
Oral Mechanism Examination
Another critical component of the CSE is the oral mechanism examination. Integrity of the lips, tongue, face, hard and soft palate, dentition, oral health, and jaw should be assessed at rest and during functional movement. The oral mechanism examination can help the clinician form hypotheses regarding the nature of the patient’s swallowing disorder. The oral mechanism examination provides a means of assessing the integrity of the cranial nerves involved in swallowing and may indicate which aspects of swallow function are impaired. The cranial nerves involved in swallowing are the trigeminal (V), facial (VII), glossopharyngeal (IX), vagus (X), and hypoglossal (XII).
In patients with chronic cough, assessment of vagal nerve function is particularly important. The glossopharyngeal nerve and the vagus nerve are often damaged together. Thus, integrity of these nerves can be assessed simultaneously. Clinicians should observe the velum (soft palate) at rest and during elevation (ie, while saying “Ah”). Vocal quality can indicate functionality of these nerves. Breathy vocal quality may indicate unilateral or bilateral vocal fold dysfunction that places the patient at increased risk for aspiration due to decreased airway protection during swallowing. There are a number of studies indicating the presence of dysphonia, including breathiness, harshness, or hoarseness, is predictive of aspiration.31, 24 Others have suggested reduced pitch elevation is predictive of dysphagia due to co-existing sensation issues associated with a superior laryngeal neuropaty.25 Clinicians may also want to elicit a gag response from their patients to assess integrity of CNs IX and X. Integrity of the patient’s voluntary cough can be used to assess glossopharyngeal and vagus nerve function. Objective measures of voluntary cough, using tools such as a pneumotachograph, have high sensitivity and specificity for detecting aspiration risk.26 Smith-Hammond found significant reductions in peak expiratory airflow in patients with dysphagia following stroke. Individuals with severe aspiration exhibited the lowest peak expiratory airflows during a voluntary cough.27 Additionally, peak expiratory flow rates are reduced in patients with Parkinson’s disease who aspirate compared to those who do not aspirate.31, 29 Finally, cough peak flow can be used to predict pulmonary complications resulting from aspiration in individuals with dysphagia.30
One method of assessing integrity of the cough reflex is cough reflex testing, in which the patient is asked to actively or passively inhale a solution containing either tartaric acid, citric acid, or capsaicin. Integrity of either a natural cough response or a suppressed cough response is assessed. Abnormal or reduced cough response following inhalation of these solutions has been found to predict risk of pneumonia in individuals with stroke in some studies but not in others.31–35
When administering a CSE, a standardized protocol of bolus administration is recommended. Standardization of bolus types, numbers of boluses, and bolus amounts allows for comparison of patient behavior across trials. Additionally, it ensures consistency across clinicians and across facilities. Typically, a CSE will include presentation of a thin liquid (often water), a pureed or pudding-type bolus, and a solid consistency. Boluses of each may be presented in varying amounts, often progressing from very small amounts and progressing to larger amounts that are considered to be more reflective of typical patient behavior (eg, cup sips of thin liquids or self-fed pudding or solid boluses). Patients are observed for any signs/symptoms of oropharyngeal dysphagia.
Oral phase issues that may be observed include reduced lip seal resulting in spillage of the bolus from the oral cavity, inefficient or ineffective mastication of solid textures, and residue within the oral cavity. Little information about integrity of the pharyngeal phase of swallowing can be gleaned from the CSE. Structures in the pharynx, such as the base of tongue, posterior pharyngeal wall, valleculae, and pyriform sinuses, cannot be visualized without the aid of instrumentation such as an endoscope or X-ray. On the other hand, signs and symptoms of aspiration can be detected during a CSE. Cough is one of the most reliable signs of aspiration.26, 27, 38 Wet vocal quality immediately post-swallow has also been suggested to have predictive value for detecting aspiration.31, 38 However, clinicians do not reliably perceive wet vocal quality when material is present in the larynx during phonation, and judgment of vocal quality lacks sensitivity and specificity for detection of aspiration.31, 40 Thus, clinicians should consider referring for or performing videostroboscopy if the voice is abnormal but should be cautious in making judgments of aspiration risk based solely on changes in vocal quality. The likelihood that a patient is going to present with overt signs/symptoms of aspiration appears to be dependent on bolus volume. Presentation of small bolus volumes of 1 to 5 mL lack sufficient sensitivity for detection of aspiration, and patients who aspirate silently may not be identified if only small bolus volumes are presented. Larger bolus volumes of 90 to 100 mL have high sensitivity for detection of aspiration, and patients who aspirate silently when presented with small bolus volumes are less likely to do so when they take larger bolus volumes.31, 41 Despite the ease of use and clinical utility of the CSE, a recent review paper showed that the sensitivity and specificity of water swallow tests compared to the standard of radiographic or endoscopic imaging was 71% and 90%, respectively, for single sip volumes, 91% and 53% for consecutive 90 to 100 mL trials, and 86% and 65% for progressively increasing volumes of water.41
If the patient exhibits no overt signs or symptoms of aspiration or dysphagia, and if the patient is medically stable, the clinician may wish to recommend an oral diet. If overt signs or symptoms of aspiration or dysphagia were observed during the CSE, an instrumental assessment such as videofluoroscopy or endoscopy is recommended.
The videofluoroscopic swallow study (VFSS), also called the modified barium swallow (MBS), is a radiographic procedure during which swallowing is viewed in real time. It is considered the criterion standard for evaluating the oral, pharyngeal, and cervical esophageal phases of swallowing. The purpose of the VFSS is to determine underlying swallow pathophysiology resulting in the patient’s symptoms of dysphagia and to determine appropriate treatment options. Patients are given a series of barium sulfate-infused boluses, ranging from thin liquid to solid, and swallowing is observed in the lateral and anterior-posterior views. As with the CSE, a standardized protocol is recommended. Because videofluoroscopy is a radiographic procedure, it is a time-limited examination. Fluoroscopy time is typically limited to 5 minutes or less.
During the VFSS, structural movements including tongue movement, velar elevation, hyoid superior and anterior movement, laryngeal elevation, epiglottic retroflexion, base of tongue retraction, pharyngoesophageal segment opening, and pharyngeal stripping wave are observed. Additionally, timing of swallowing events, including oral transit times, initiation of the pharyngeal swallow, pharyngeal transit times, and duration of cricopharyngeal opening are viewed. Clinicians should note presence of residual material in various locations including the lateral sulci, base of tongue, posterior pharyngeal wall, valleculae, and pyriform sinuses as well as the patient’s response to the residue. In some instances, very small amounts of residual material remaining in the pharynx after the swallow will create a sufficient irritant to elicit the patient’s urge to cough or clear his or her throat. Penetration, defined as liquid or food entering the laryngeal vestibule but not spilling below the vocal folds, and/or aspiration, defined as liquid or food spilling below the vocal folds, should be noted as should the underlying pathophysiologic problem that led to the finding. Again, the patient’s response or lack thereof to penetration or aspiration should be reported. Of particular importance is whether the patient responds with cough or throat clear to aspiration, an event known as “silent aspiration” when there is no response.
One common finding on the VFSS is the presence of a cricopharyngeal (CP) bar at the pharyngoesophageal segment. A CP bar is defined as an unremitting prominence of the CP muscle during a swallow when it should relax as seen in lateral view on radiographic imaging (Figure 7–1). The CP bar is thought to be significant when it occludes more than 50% of the lumen when filled with contrast and relates to its reduction of maximal dimensions of the upper esophageal sphincter (UES), causing presumed increased intrabolus pressure upstream to the UES.42
Figure 7–1. VFSS view of a cricopharyngeal bar in an individual after radiation treatment for head and neck cancer.