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The Dose Transcript for April 5, 2023

Host: Dr. Brian Goldman

STORIES FROM THIS EPISODE

BRIAN GOLDMAN: Hi, I'm Dr. Brian Goldman. Welcome to the dose. If you have asthma, you almost certainly get short of breath or wheezy at times. But those symptoms can also point to many other conditions, which means that misdiagnosis can be a problem. So today we're asking, how do I know if I have asthma? Hi, Sean. Welcome to the dose.

SHAWN AARON: Thank you, Brian. I'm glad to be here.

BRIAN GOLDMAN: How often do you see patients who have been diagnosed with asthma but in fact don't have it?

SHAWN AARON: Oh, I would say about 30% of the patients I see in my practice have been diagnosed with asthma, but don't have it.

BRIAN GOLDMAN: Wow. That is incredible. And I guess that's one of the big reasons why we wanted to talk to you. But before we begin, can you give us a. Hi, my name is tell us what you do and where you do it. You can just adlib just a line or two.

SHAWN AARON: Sure. My name is Shawn Aaron. I'm a physician. I'm a doctor. And specifically, I'm a lung doctor. We call that a respirologist. I see patients for about 40% of my week and then the other 60% of the time I'm doing research in asthma and COPD. I work at the Ottawa Hospital and at the University of Ottawa.

BRIAN GOLDMAN: Great. Glad we've got you on board. Here we go. I've read from time to time that the prevalence of asthma is rising. And I was wondering, is that still the case?

SHAWN AARON: Yeah, it is the case. We have statistics from both Alberta and from Ontario that show that the prevalence of asthma from 1995 to 2015 rose almost three fold. So that, for instance, in Alberta, only 4% of people in Alberta in 1995 were diagnosed with asthma, and that prevalence rose to 12% by 2015. And similar numbers for Ontario.

BRIAN GOLDMAN: And we're talking about adults as well as children.

SHAWN AARON: Yeah, we're talking about both adults and children. The only thing I should tell you, just to to be fair to the data, is that even though prevalence is increasing, it looks like incidence is starting to drop so that new diagnoses of asthma in the last five years are lower than they were five years ago.

BRIAN GOLDMAN: Is there a gender divide when it comes to asthma?

SHAWN AARON: Yeah, there definitely is, Brian. You know, asthma is very common in in children. So, for instance, almost 15% of kids are diagnosed with ALS. But there is a gender divide so that in kids prior to puberty, asthma is much more common in males than in then female children. But once puberty hits and patients go go into their later teenage years and early adulthood, the prevalence of asthma in men and women reverse. So that in kids, boys are more commonly have asthma than girls. But once people become adults, asthma is much more common in women than it is in men.

BRIAN GOLDMAN: Do we know why that's the case?

SHAWN AARON: Well, some of it must have to do with sex hormones and and puberty. But it's unclear how much of a role sex hormones are exerting. Some of it may have to do with women simply being more prone to autoimmune diseases, that is, diseases whereby the immune system kicks in and attacks the body. And we know that asthma is an inflammatory disease in the airways. And if women have more predisposition to allergies, and autoimmune phenomenon that may explain why they're more predisposed to asthma than than men.

BRIAN GOLDMAN: Overall, it seems as if the prevalence of asthma is quite high in our society. What are some of the reasons for that?

SHAWN AARON: Yeah, there are a whole bunch of reasons and and some of it may be related to climate change and pollution. So, for instance, with climate change, as our climate warms, that is obviously going to prolong the allergy season so that, you know, there's going to be more tree and grass pollen in the air and there's going to be more ragweed pollen in the fall and it's going to last for longer because, you know, our hard frosts are delayed in the fall now. So so some of the increase in asthma may simply due to the fact that because we're having a warmer climate, we're more exposed to outdoor allergens, that is tree grass pollen and fungal spores and also ragweed pollen, which can provoke asthma. Another reason may be air pollution. Not such a big deal in most of Canada, because our air quality in Canada is relatively good, but in more polluted parts of the world or in the developing world where pollution is a big problem. Pollution can definitely aggravate and exacerbate asthma. There are other, more complex issues. Asthma is about twice as common in obese adult females. That is, women with a BMI greater than 30. And we don't know why that is, but we think that fat cells may actually provoke asthma by secreting inflammatory mediators. And we know the prevalence of obesity in the last 20 years has increased in North Americans. And so part of the reason why asthma may be more common is simply because we have more obesity in our society.

BRIAN GOLDMAN: Well, of course, I'm an emergency physician, so I know a lot of the symptoms of asthma, wheezing, maybe a thin bit of mucus, but mostly dry cough, some shortness of breath. What are some of the sneaky symptoms of asthma that people might not realize are, in fact, attributable to asthma?

SHAWN AARON: Well, definitely one of them is that nocturnal symptoms. What that means is overnight symptoms. We know that asthma is very sensitive to corticosteroids and our body produces steroids naturally from our adrenal glands. But these steroid levels actually fall to their lowest level around three or four in the morning. And so people with asthma that's uncontrolled at three or four in the morning when their levels of endogenous steroids are at their lowest, these people may wake up with asthma symptoms. So they may wake up with cough or shortness of breath or wheeze, and their sleep may be disrupted. So one of these sneaky manifestations of asthma is if sleep disruption. Another one is that we see this commonly and especially in children. Mom may bring the child in and say Johnny seems healthy, but but his gym teachers tell me that he can't keep up with the other kids and he's having trouble in his hockey league because he gets short of breath and has to has to go off the ice. And again, that could be a manifestation of asthma that's untreated in these children or adults who who have exercise limitation because of shortness of breath from asthma. So asthma can can make its way into people's lives and sort of it's sort of sneaky ways and can really impact on quality of life. And that's why it's so important for doctors to make the diagnosis.

BRIAN GOLDMAN: And we're going to be spending a lot of time talking about exactly that. The first question I wanted to ask you, though, regarding diagnosis is misdiagnosis. How often is asthma misdiagnosed?

SHAWN AARON: Well, we've done two studies now in Canada where we recruited people who had been diagnosed with asthma in the last five years by doctors. And we actually brought them in to the study and and tested them extensively for asthma. And in fact, if we couldn't find asthma, we gradually withdrew their asthma medications and kept testing them until they were completely off medicines. And we found that 30% of people who were labeled with asthma had no evidence of active asthma when we tested them and withdrew their asthma medicines. So it does suggest that there are a number of patients in Canada who have been labeled with asthma who no longer have active asthma. Now, that doesn't mean they were all misdiagnosed, Brian, because some of them may have had asthma when they were diagnosed five years ago, but now they're asthma is in remission. And some of them, they may have been misdiagnosed from the beginning. But all we can say is that about 30% of people who are labeled with asthma don't have any evidence of active asthma. When we when we assess them very thoroughly.

BRIAN GOLDMAN: And, you know, Shawn, I was taught in medical school that asthma is a reversible disease. But but the question I want to ask you that I think is pertinent to what you've just said is are there lingering markers that someone has the condition that we call asthma, even though they may not have bouts of wheezing at that time in their life?

SHAWN AARON: Well, yeah. I mean, there are there are obviously clinical clues you can ask. So you can ask, as you said, about cough, chest tightness, wheezing, shortness of breath to try to assess if they're still having symptoms of asthma. You can also ask about nighttime symptoms to see if because that's also a marker of poor control. Most people with asthma have rescue inhalers. And you can ask them how often do you need to reach for your rescue inhaler in a week? Someone who's well-controlled with asthma is not going to be needing the rescue inhaler and they're not going to be waking up at night and they're not going to be limited in their activities because of their asthma. They'll be able to play hockey or go hiking without becoming wheezy or short of breath. Obviously, the other things you can do to assess asthma control if you're able to, is to order a simple spirometry test. Which is a lung function test where the patient blows into a tube and we assess how how much air and how quickly they can blow out into that tube. It's very simple test and it will assess if the patient has any evidence of asthma objectively on their breathing test.

BRIAN GOLDMAN: How surprised were you to discover that as many as 30% of the patients you assessed who were diagnosed with asthma have no indications of asthma at the time of when you assess them? When you did your research?

SHAWN AARON: Well, I wasn't that surprised because the reason I did the research was because I was seeing this problem in my clinical practice, you know, where people would be sent to me with a diagnosis of asthma, and we would be able to confirm that they didn't seem to have asthma. And the other thing we know is that there is a proportion of patients whose asthma will go into remission, who will who will require asthma medicines. You know, in 2003, but maybe by 2008, they no longer need those medicines because their asthma has disappeared, at least temporarily. So, you know, it didn't surprise me much that 30% may have been overdiagnosed or didn't have asthma. But when we assess them, I mean, the other thing the other flip of the coin here, on the other hand, is that there are a lot of people in Canada who are suffering with asthma, who are undiagnosed, where people are are suffering from shortness of breath or wheeze or prolonged cough and have asthma and have not been diagnosed and not been treated.

BRIAN GOLDMAN: Why do you think that is?

SHAWN AARON: Well, again, that's a bit complex, but one of the major reasons is because access to lung function testing is relatively poor in most Canadian provinces, in most Canadian communities. So, for instance, you know, the best way to make a diagnosis of asthma is to have a patient do breathing tests. And what we do is we often test them when they come into the lab, and then we give them a bronchodilator, a medicine called Ventolin to breathe in, and we test them again 20 minutes later. And patients with asthma are going to show evidence of airflow obstruction, which reverses after the bronchodilator. So this is a perfect test to make a diagnosis of asthma, But this test is actually relatively hard to get in communities, even though the test only takes 20 or 30 minutes. It's perfectly safe and it only costs about $40. The problem is that the government in many communities restricts access to the testing and restricts laboratories from doing the testing. So it's hard to get the tests done. And patients have to often go to a hospital or a local hospital lab to do this test. And therefore, if the testing is hard to get, then it's hard for doctors to make the diagnosis and actually confirm the diagnosis.

BRIAN GOLDMAN: What percentage would you estimate of Canadians who have asthma Don't know it.

SHAWN AARON: Well, I'm going to tell you what our study is found. So we've done a study. We're just finishing it up now, a study of over 2500 Canadians who were recruited from the community randomly who were complaining of lung symptoms, shortness of breath or wheeze or cough in the last six months. And we recruited these people from all across Canada and we tested them for asthma, COPD, And we found that 20% of Canadians who are complaining of respiratory symptoms have clear evidence of asthma, COPD, when we do lung function testing on them. So that's an awful lot of people. Now we only recruited people with symptoms, so we didn't recruit everyone from the population, but population level Studies suggest that about 4 to 5% of the population of Canada probably has undiagnosed asthma.

BRIAN GOLDMAN: That's of the total population?

SHAWN AARON: Yeah.

BRIAN GOLDMAN: Okay. That's a lot.

SHAWN AARON: Yeah, it would be a lot. I mean, you know, diagnosed as much as 8% of the population, but there may be an additional 4% that remains undiagnosed.

BRIAN GOLDMAN: Let me go, you know, very quickly to the other side. When it comes to asthma, misdiagnosis, what are some of the other conditions, the most common conditions that can have the same symptoms as asthma but are not asthma?

SHAWN AARON: Very good question. In our study, we looked at that and we found that the commonest things that mimic asthma are heartburn because heartburn can cause protracted and prolonged coughing and nasal congestion and what we call post nasal drip or allergic rhinitis. So that is patients who have chronic nose dripping, that drips down the back of the throat and causes coughing and sometimes a little bit of wheezing and sputum production. Those are the two commonest things that will mimic asthma. And neither of those conditions is life threatening. So that's the good news. But we did find that in the patients in whom we excluded asthma in our study, that some of them had life threatening conditions that had been misdiagnosed as asthma. So things like congestive heart failure that's misdiagnosed as asthma or myocardial ischemia, that is coronary artery disease causing angina, that causes shortness of breath and chest tightness. That's misdiagnosis, asthma or other very severe conditions like pulmonary fibrosis or upper airway obstruction so that we're misdiagnosed as asthma. So ultimately, of those who were misdiagnosed, about 10% had serious medical conditions that were called asthma when they worked.

BRIAN GOLDMAN: And, you know, as an emergency physician, I certainly know the basic treatments for asthma. There's the rescue inhalers, the bronchodilators like salbutamol, that that that relax the muscles, that line the airways and open up the breathing passages. And then there's steroids, corticosteroids, inhaled corticosteroids and all that reduce, they get rid of the sticky mucus, the inflammation. What other treatments are out there that that have emerged as important in the treatment of asthma?

SHAWN AARON: Well, I mean, the bottom line is, as much as the disease of inflammation in the airways and inflammation in the airways, if you if you want to think of it in late terms, think about if you get a cut on your hand and the cat gets infected, it'll get swollen, it'll get red, it'll start to weep fluid and perhaps pus. That same thing is happening in the airways, in asthma. The airways are just tubes that bring air into the lung and they're getting swollen and red. They're releasing mucus. And the and the muscles around the airways are getting tight, which is also constricting the airway and making it difficult to breathe because that tube is getting narrower and narrower. So the bottom line is that the treatment of asthma has to involve anti-inflammatory medications and the best anti-inflammatory medication we have, you've already mentioned it is inhaled steroids. So those are the cornerstone of asthma therapy. Now, we often mix the inhaled steroids with bronchodilators that open up the airways. And we have a lot of medicines now that are combined long acting bronchodilators and inhaled steroids. And we can give those to people if they have mild asthma, they can take those medications only when they need it. So only when they're experiencing symptoms, they can take two puffs of of an inhaled steroid, long acting bronchodilator medication. But if they have more moderate or severe asthma. They often need to take these medications regularly and on a daily basis.

BRIAN GOLDMAN: Last question I'm going to ask you. You know, we see people in the emergency department who have severe shortness of breath and what are what are the indications? You know, we hope that people don't end up in the emergency department. But if but if they should be going, can you can you give us an indication of what kinds of symptoms should make people think about going to the E.R.?

SHAWN AARON: Yeah, I mean, basically, I,I'm hoping that most as medics, I don't need to go to the E.R.. I'm hoping that many of them would have an action plan in place so that they've been told what to do by their doctors if they get worse. And some of them should even have an action plan where they have prednisone at home to use if they need it. But the bottom line is, if you have asthma and you're experiencing significant shortness of breath to the point where you're short of breath simply talking or watching television or resting, you need to go to the emergency department or see at least see a physician that same day to get treated.

BRIAN GOLDMAN: Let's hope it doesn't come to that. But people are informed. And that's because of you. Dr. Shawn Aaron, that was a fantastic interview. I want to thank you for speaking with us.

SHAWN AARON: My pleasure. I'm glad to be of help and thank you for having me.

BRIAN GOLDMAN: Dr. Shawn Aaron is a respirologist at the Ottawa Hospital and professor of medicine at the University of Ottawa. Here's your dose of smart advice. Asthma is one of the most common respiratory diseases, affecting 3.8 million Canadians, according to one study. You can get asthma at any age, though it's more common in kids. Asthma in that age group is often triggered by allergies in adults. Asthma often reappears in people with a history of childhood asthma, or it may come out of the blue. The typical symptoms include wheezing, coughing and chest tightness. Symptoms of severe asthma include being too breathless to eat, speak or sleep, rapid breathing, fast heartbeat and signs of severe respiratory distress. Other symptoms of asthma include wheezing and dry cough at night. Poor exercise tolerance at school is a subtle indication of asthma in kids. Getting an accurate diagnosis of asthma is important. Despite that, as many as 4 to 5% of Canadians may have symptoms of asthma that are undiagnosed. On the other hand, symptoms that are chalked up to asthma can be due to other diseases. As many as 30% of Canadians diagnosed with asthma in the last five years do not have it at present. Here's the bottom line If you have symptoms of asthma, such as wheezing, chest tightness and dry cough, see your health care provider to get lung function testing. That is the simplest and most direct way to confirm that you have asthma. Effective treatments include inhaled medications that open up the air passages and corticosteroid medications that reduce airway inflammation. There are new and expensive treatments for people with hard to manage asthma. One of the main aims of treatment is to avoid a trip to the e.R. Still, if you have severe wheezing or shortness of breath at rest, or when you try to speak, call 911. If you have topics you'd like discussed or questions answered, our email address is the dose at cbc.ca. If you like this episode, please give us a rating and review wherever you listen. This edition of The Dose was produced by Isabelle Gallant. Our senior producer is Colleen Ross. The Dose wants you to be better informed about your health. If you're looking for medical advice, see your health care provider. I'm Dr. Brian Goldman. Until your next dose.

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How do I know if I have asthma?- Transcript

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