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Chronic Cough Diagnosis: Definitions, Differentials, Physical Exam & Functional Tests
Julia Casazza • Oct 30, 2023 • 35 hits
Affecting up to 5% of American adults, chronic cough is the most common reason patients visit their primary care physician. Many of these patients will end up with a referral to otolaryngology, even if the cause of their cough is gastrointestinal, pulmonary, or neurologic in nature. For this reason, all otolaryngologists should familiarize themselves with how to evaluate chronic cough. Dr. Karuna Dewan, laryngologist at Louisiana State University Health Sciences Center-Shreveport, sat down with BackTable to share pearls on evaluation of this common complaint.
This article features excerpts from the BackTable ENT Podcast. We’ve provided the highlight reel in this article, but you can listen to the full podcast below.
The BackTable ENT Brief
• A cough must persist for at least eight weeks before it is considered chronic.
• When taking a history on a chronic cough patient, pay attention to triggers of cough. While not always perfectly specific, understanding what triggers coughing can go a long way in determining the etiology of cough.
• Physical exam for a patient with chronic cough should include a head & neck exam, cardiopulmonary auscultation, and scope examination. Swallowing evaluation is also beneficial.
• About half of all patients reporting globus will have asymmetry between their vocal folds, which is visible on scope examination.
• Functional endoscopic evaluation of swallowing (FEES) and modified barium swallow tests evaluate swallow function. Modified barium swallow requires radiation exposure, whereas FEES does not.
• Any patient with concern for aspiration needs a chest x-ray to evaluate for silent pneumonia.
Table of Contents
(1) Chronic Cough: A Multidisciplinary Problem
(2) Taking a History for Chronic Cough
(3) Physical Exam for Chronic Cough
(4) Functional Tests for Chronic Cough
Chronic Cough: A Multidisciplinary Problem
Cough lasting eight weeks or longer is “chronic.” Physiologically, coughing is a response to laryngeal stimulation, so the goal of treatment is to reduce coughing to a tolerable level. When working up patients for this concern, Dr. Dewan emphasizes that cough can be respiratory, gastrointestinal, allergic, neurologic, or post-infectious in etiology. For this reason, she urges a multidisciplinary approach to chronic cough.
[Dr. Karuna Dewan]
Yes. Cough that's persistent longer than two months is by definition chronic cough. We're seeing a lot of people who had COVID or had a URI, like upper respiratory infection or some cold flu type thing, and they're still coughing. For up to two months, up to eight weeks, that can still be the remnants of that initial infection. After it's been two months, then we start to think that this has become a chronic condition. Chronic cough is pervasive. It's expansive. There are estimates that somewhere between 9% and 30% of the population suffer from chronic cough. It's the single most common reason adults go to see the primary care physician.
It becomes even more interesting because we know that cough has a function too. Cough has a basic function. You don't want to completely prevent cough because it has a positive effect also. It keeps the pulmonary alveoli open. It's used to expel things. If you're eating or drinking and something goes down the wrong way, you have to cough to get it up. Cough can be voluntary. We all cough to clear our throat very often.
Then cough is a response to stimulation in the larynx, in the throat, and in the lower respiratory tract. Stimulation, which can be foreign particles, can be an allergen, can be pretty much anything. We need to do what we often as physicians call pulmonary toilet to get that stuff out of our lungs. Entirely preventing cough is not the goal but really making it so that people can live a comfortable life in concert with the cough.
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Taking a History for Chronic Cough
As multiple organ systems can account for chronic cough, history-taking assists the otolaryngologist in determining the cause of cough. Patient-identified triggers for coughing provide particular insight into the cause of cough. Common clues (and the pathologies they suggest) include cold air (irritable larynx), swallowing (esophageal problems or mass lesions), environmental stimuli (allergies), eating (aspiration), nighttime awakenings (reflux), and exercise (asthma, subglottic stenosis, paradoxical vocal fold motion). When taking a medication history, pay attention to ACE inhibitors, which are well-known causes of cough; patients with ACE inhibitor-triggered cough likely require re-referral to their primary care physician for adjustment of their anti-hypertensive regimen.
[Dr. Gopi Shah]
When these patients come to you, what kinds of questions do you usually ask them? What are you looking for in your history? What is something that helps you tease out etiology, treatments, risk factors?
[Dr. Karuna Dewan]
In the diagnosis of chronic cough, the history, the HPI, is really important. I start with what makes you cough. Can you identify triggers? It's 50-50. Some patients will know exactly what makes them cough. Some patients will not know at all, but are there certain smells? Does exercise make you cough? Do you cough when you eat or drink or do you cough after you eat or drink? Is it change in temperature? A lot of people will say, "When the air conditioning hits me, I'll cough. When I sit in front of a fan, I'll cough." Is coughing triggered by talking or by laughing? Does something make your cough stop?
One of the key things that I like to ask is, "Do you wake up in the middle of the night coughing? Do you feel short of breath? Do you feel like your voice has changed?" For those people who cough when they eat or drink, "Do you feel like you also have difficulty swallowing? Are there some foods that you avoid because you think they're going to trigger a cough? Do you have seasonal allergies? Do you have allergies to pets? Have you seen an allergist?"
Then, of course, "What treatments have you tried? What has worked for you?" I like to ask people, "When did your cough start? Do you remember being sick when your cough started?" It's very common to hear, "I had this cold, flu, something, and everything else got better, but my cough never got better." "Do you smoke? Does someone in your home smoke?" Then, I ask them all these questions, and I usually ask them about their medication list, and then I will look at their medication list pretty carefully.
Physical Exam for Chronic Cough
Physical examination of the coughing patient should evaluate all organ systems potentially involved. Upon entering the room, watch how the patient breathes: are they hunched over in a tripod position? Is their breathing noisy? Cardiopulmonary auscultation is highly beneficial; certain physical exam findings hasten diagnosis, such rales, as heard in decompensated heart failure, wheezing in asthma, or crackles in interstitial lung disease. As always, perform a comprehensive head and neck exam, keeping in mind that sinonasal concerns (particularly allergic signs or enlarged adenoids) can trigger coughing associated with postnasal drip.
The comprehensive physical exam is followed by the scope exam. A plain flexible scope allow for assessment of structural problems (masses, lesions, leukoplakia, ulcers) and sinonasal factors. Stroboscopic exam visualizes mucosal wave. About half of all patients with globus sensation have asymmetric mucosal wave between their left and right vocal folds. This asymmetry causes patients to feel as if something is stuck in their throat.
[Dr. Gopi Shah]
All right. In terms of physical exam, tell me what your exam is like in clinic.
[Dr. Karuna Dewan]
I like to tell the residents, "Your exam begins the moment you walk in the room." When I walk in the room, I'm looking at this patient and I'm looking to see, are they on supplemental oxygen? Did they seem short of breath when they're talking to me? Did they seem short of breath when they were walking down the hallway towards the room? Does their voice sound wet? Do they cough while I'm taking the history? Because that's telling. Sometimes they'll say, "This cough is really killing me. It coughs all the time," but I talk to them for 20 minutes, and they don't cough. What is their body habitus? Are they thin? Are they obese? Are they sitting up straight or are they tripodding and hunched over? Do they have edema of their hands or feet that I can see?
I do a comprehensive head and neck exam essentially. Start at the top and look at their eyes, look in their ears, look in their nose. I'm looking in their nose to look for rhinorrhea, signs of allergies. I do a complete oral cavity and oropharyngeal exam, masses, lesions, ulcers, things like that. I listen to the heart and lungs, which I think is a lot of things that most ENTs don't do. I'm listening to their heart and lungs because people can cough when they have fluid overload. People can cough when they have asthma, when they have pulmonary fibrosis. I'm listening to hear for other sources.
Then everybody gets a scope exam and that's part of coming to see a laryngologist is I'm going to look at your larynx. I think it's really important that if somebody's been coughing for two months, that they get a laryngeal exam because too often we miss things that are-- we miss cancer. It's really important to look. I like cough and I think it's interesting. I show all my residents, and even a lot of the patients, this diagram. It has cough at the top, and it has six systems listed. Your cough can be cardiac in origin. Patients can have CHF, and you can tell that by looking at them, by looking at their hands or feet. Are they puffy? Do they have pitting edema?
It can be pulmonary in origin and that's part of why I listen to everybody's chest. I ask them about their smoking history. I ask them about their medications. It can be gastrointestinal in nature. As we know, branches of the vagus supply the esophagus, the pharyx. Really irritation anywhere between your teeth and your stomach can cause somebody to cough. You really owe it to the patient to examine that area. Cough can be nasal/sinus/allergy in origin. Cough can be laryngeal and I think that's why it's important to image the larynx. Then lastly, when we've eliminated everything else, cough can be neurogenic, and that's what we've alluded to a little bit and we'll get into a little bit more.
[Dr. Gopi Shah]
Now, thank you for going through that system-wise because that helps you think of the differential, right?
[Dr. Karuna Dewan]
Right. That's how I like to organize it so that I know I'm not missing something. I go in order. We've created a worksheet for the patients because when patients come to me, they've seen a smattering of people. Some come from pulmonology, some come from GI, some come from allergy. We've created this worksheet for the patients where they can fill out the date in which they had what tests. If they have the results, they can fill out the results so that when they come to me, I act almost like a secretary where I'm collating all this information from all the different specialists so we can try to figure out what's left, what still has been unturned.
Functional Tests for Chronic Cough
In addition to standard laryngologic examination, workup of chronic cough includes evaluation of the gastrointestinal, pulmonary, and neurologic systems. Functional endoscopic evaluation of swallowing (FEES) directly visualizes patient swallow without radiation. During FEES, clinicians visualize how patients swallow saliva and then foods (starting with purees and then working up to solid foods, all of which are dyed to aid in visualization). Based on FEES results, patients with esophageal dysphagia, including conditions such as strictures, achalasia, and Zenker’s diverticulum, can undergo transnasal esophagoscopy or modified barium swallow. If a neuromuscular esophageal problem, such as diffuse esophageal spasm, is suspected, esophageal manometry should be ordered. Any patient with concerns for aspiration needs a chest x-ray to evaluate for silent pneumonia.
[Dr. Gopi Shah]
All right. In terms of testing, and I think that we're better overall as ENTs whether it comes to hearing loss, to co-op, to getting targeted testing, tell us about the testing, what's out there, and how you decide what you're going to get in terms of the role of a chest X-ray versus a CT chest to, does this patient need a video swallow now that I've had my eating 10 and my TNE, or my FEES? Spirometry, are you getting that? Is that something that you do talk to palm about?
[Dr. Karuna Dewan]
It depends where on the differential we're looking. Like I said, about half of my practice is dysphagia. My workhorse tends to be a modified barium swallow. The modified barium swallow is done by a speech pathologist in radiology, and it's a dynamic study. Patients get a variety of bolus sizes and bolus consistencies, and they're administered by the speech pathologist. The nice thing about the modified barium swallow is they can also do treatment and exercises and things. They can practice things like the chin tuck, head turn for somebody with unilateral paralysis and see on fluoroscopy, does it help? Does it change the direction of bolus?
I order a modified barium swallow for those patients who I think they may have an esophageal problem essentially. I think they may have a narrowing at their UES. I think they may have achalasia. I'm basically looking to see, how does food move from the oropharynx into the esophagus and down the esophagus. I will order an esophagram, which is different, which is one consistency. It's just chugging essentially barium. I will order that for somebody who I think may have a Zenker's diverticulum. When I want to see maximum dissension of the esophagus or the PE segment, that's when I'll order an esophagram.
I order things. I will definitely refer to pulmonology, but I order pulmonary function testing in those patients that I think may have subglottic stenosis, may have PVFM. A lot of times it's COVID patients, patients who previously had COVID. They're waking up coughing. They feel short of breath. I want to know what their underlying lung status is too. For those patients, I will order pulmonary function testing. I don't do that terribly often because a lot of times patients have come to me from pulmonology. I will order a chest X-ray actually fairly often.
The chest X-ray is for a patient in the office that I've done a FEES for, and I can tell that they look like they're aspirating fairly often, but they say that they haven't been sick. They haven't had any pneumonias. They're also the patient who jus-- you tell them, "Hey, let's thicken your liquids," or, "Let's talk about maybe not drinking thin liquids," or, "Let's talk about doing some maneuvers." They don't really want to participate. They're like, "I'm doing fine." I like to get a chest X-ray so that we have something to talk about. Maybe they are doing fine.
There are plenty of people who are functional aspirators out there, but maybe they also have an undiagnosed pneumonia. Then we have an X-ray to talk about, to show them and say, "Look, there's stuff in your lungs. I'm worried about what's going to happen to you. I don't want you to get sick. Let's change your diet." I'm very fortunate in our Voice and Swallow Center here that we also have a dietician who works with us very closely. When it comes to modifying diets and suggesting alternative things for people, we have a very facile dietician who's really helpful.
Dr. Karuna Dewan
Dr. Karuna Dewan is an otolaryngologist / head and neck surgeon with Ochsner LSU Health in Shreveport, Louisiana.
Dr. Gopi Shah
Dr. Gopi Shah is a practicing ENT at UT Southwestern Medical Center in Dallas, TX.
Cite This Podcast
BackTable, LLC (Producer). (2023, June 20). Ep. 116 – Chronic Cough in Adults [Audio podcast]. Retrieved from https://www.backtable.com
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