Non-pharmacological treatment for chronic cough valuable while new treatments in the pipeline

While promising new treatments for chronic cough are in the pipeline, no licensed treatments are currently available.That means non-pharmacological treatments remain an extremely valuable tool, attendees at the Canadian Respiratory Conference in Toronto in April were told by leading experts. Defined as a cough lasting eight weeks or more, chronic cough is particularly challenging to diagnose and treat because it often has multiple possible causes and can be due to more than one condition, said conference speaker Dr. Imran Satia, an expert in the field of chronic cough and assistant professor at McMaster University for the department of medicine, respirology. Cough is the most frequent symptom seen by both primary care physicians and respiratory specialists. For patients, chronic cough can be frustrating or even disabling, significantly impacting their quality of life.Naming the coughDr. Satia summarized the different kinds of chronic coughs and the challenges of naming and treating them and spoke about advances in research and potential treatments.“Out of those patients with chronic cough, there'll be a proportion you will treat and their cough will get better. We call those people explained chronic cough,” he said, noting that the cause is often nasal disorders, asthma, bronchitis or gastroesophageal reflux disease.“Unfortunately, there's a group of people who have what we call refractory chronic cough or (those with) unexplained chronic cough. In refractory chronic cough, you've been able to identify an underlying disease, you've carefully treated this disease, but the cough still persists,” he said. “If you investigate the patient and can't find an underlying disease, and they have normal methacholine, normal blood count, normal CT scan, and there’s literally nothing else that you can identify, we often call that unexplained chronic cough.”Dr. Satia pointed out that this nomenclature can be confusing, and frustrating for patients. “I say to a patient, ‘You've had a chronic cough for 15 years. We investigated and we can't find a cause.’ And the patient says, ‘So doctor, what's wrong with me?’ And I say, ‘Your diagnosis is unexplained chronic cough.’ They'll look at you in an unusual way and think you are not very good,” he said.Studies show that refractory or unexplained chronic cough can indicate a neurophysiological disorder, Dr. Satia said. “So I would see one of our aims as a community is to give some kind of pathophysiological diagnostic label, something like cough factor, sensitivity syndrome, neurogenic cough, apathetic cough, something that tells you something about pathology rather than saying you have refractory or unexplained chronic cough.”Read: Managing mild and very mild asthma in preschoolers, children and adolescentsDr. Satia explained the pathology behind refractory and unexplained chronic cough. Research shows that the underlying mechanism is something sometimes called cough hypersensitivity syndrome: The nerves that control cough, like the vagus nerve, which innervates the lungs and the throat and sends signals to the brain and that system have become hypersensitive and hyperresponsive.“We think the reason people are coughing is that there's something wrong with this pathway, either the peripheral vagus nerve here or the central mechanism. That’s why new therapies are designed to suppress those neuronal responses.”With limited options in the treatment paradigm for refractory or unexplained chronic cough, P2X3 receptor antagonists have shown great promise in clinical trials, he said.Gefapixant is a medication that has completed clinical development from phase 1 to phase 3 and is currently under regulatory review by the European Medicines Agency, the U.S. FDA, MHRA and Health Canada. Another p2x3 antagonist called camlipixant has shown promise in phase 1 and phase 2, with phase 3 trial currently ongoing.Currently the off-label treatments that are used for chronic cough are morphine, pregabalin, gabapentin and almotriptan. “They're not licensed but we use them. If you have access to good speech therapists, then that's another very good option to try and desensitize the central nervous system.”Speech-language pathologistSpeech-language pathologist (SLP) Kim Smith, of Grimsby, Ont., spoke at the conference on how SLPs and other healthcare practitioners can offer a viable non-pharmacological treatment for chronic cough.SLPs work in tandem with other medical practitioners, ensuring underlying causes of cough are ruled out or treated.The treatment begins with thorough assessments, including detailed patient histories and interviews to understand the nature of the cough, whether it is reflexive or voluntary. She investigates cough triggers (e.g., talking, laughing, fumes), the urge to cough and sources of irritation. She performs laryngeal exams to detect tension or irritation and may use laryngoscopy for further diagnosis and visual feedback. She assesses for paradoxical vocal fold motion, other voice disorders, and respiratory patterns. Education about the physiology and function of the cough and larynx is crucial for patient understanding and motivation.“The first and most important thing is that we need to be sure we've ruled out or treated underlying causes of cough. So we want to make sure there's nothing sinister or scary going on,” she said.There are several key pieces to successful treatment, according to Smith.EducationEducation about the physiology and function of the cough and larynx is crucial for patient understanding and motivation. “Educating patients on the cough and irritation cycle and that feedback loop, that cough begets irritation, irritation begets cough, and so on and so on and so on is important. A big piece is helping patients understand that a cough is not always necessary, and so by the time they’ve reached me, hopefully, their physician has told them that this cough is not helping them in any way.”Cough suppressionCough suppression techniques are central to SLP treatment and involve increasing patient awareness of the urge to cough, using distraction or suppression strategies (e.g., hard swallowing), and respiratory retraining (e.g., lower abdominal breathing). Desensitization training helps patients suppress coughs in the presence of irritants. “Anecdotally, the most beneficial or effective suppression technique is a hard swallow. Essentially what we're doing here is replacing one behaviour with another. So when you have an urge to cough, for example, a tickle in the throat, rather than responding to that sensation with a cough or throat clear, you're going to respond to it in a different way.”Addressing irritation Laryngeal irritation is often a presumed entity, said Smith, even when she can't see irritation on scope. “If I'm identifying in the initial evaluation that there may be some irritating behaviours, for example, dryness, high alcohol intake, smoking, vaping, high exposure to certain irritants, we do our best to moderate those and then if appropriate, I'll use some voice therapy and retraining for those patients for whom dysphonia is a coexisting issue.”MotivationSmith emphasized the importance of psychoeducational counselling and motivational interviewing to enhance patient engagement and confidence.“Eliciting the motivation and their ability to apply the strategies are incredibly important. It's not going to work if someone's looking for a quick fix, if they want a magic wand or an injection or a med. This is very time-consuming, and it can be very frustrating at times. Interestingly, anxiety in a fair number of patients is co-existing with chronic cough.”She noted that emerging research explores new techniques like expiratory muscle strength training and cough desensitization therapy using capsaicin in a nebulizer.Treatment efficacySmith noted that studies, like those done by SLP Anne Vertigan, show outcomes from this therapy include decreased objective cough counts, improvements in overall symptom scores and cough quality of life, as measured by the Leicester cough questionnaire. “There have been a few other studies that have shown improvement in non-cough symptoms such as dyspnea, upper airway sensitivity and dysphonia, as well as reduced cough frequency and reduced urge to cough,” said Smith. Smith recommends the Living Well with Chronic Cough guide on the Respiplus website, which provides strategies and information for patients. She also acknowledges the potential for other professionals, such as physical therapists and respiratory therapists, to administer this type of therapy, especially because waiting lists can be long for SLPs.Newly available therapy a turning point for many patients with Alpha-1 antitrypsin deficiency

Non-pharmacological treatment for chronic cough valuable while new treatments in the pipeline

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