Asthma and COPD: What's the Link?

Asthma and COPD are similar in many ways. They are also different in many ways. Here is a list of the differences between asthma and COPD. Asthma vs COPD Years ago, asthma was an umbrella term under which all lung diseases fell, including COPD. Today, asthma is no longer considered an umbrella term. Today, asthma is a disease entity on its own. And, as a twist, COPD is now considered an umbrella term. The two most common diseases that fall under the umbrella of COPD are chronic bronchitis and emphysema. COPD is never asthma. But, sometimes asthma can become COPD. Differences in symptoms Asthmatics only experience symptoms during asthma attacks. People living with COPD may experience some symptoms even on good COPD days.1 When people living with asthma experience symptoms they are generally referred to as asthma attacks. When people living with COPD experience new or worsening symptoms they are generally referred to as COPD flare-ups. Asthma symptoms are completely or almost completely reversible with time or treatment. COPD symptoms are only partially reversible or not reversible at all.1 Asthma symptoms only occur during asthma attacks. COPD symptoms may be present to some degree all the time. Asthma vs COPD over time Asthma is usually considered a periodic disease. This means symptoms only occur sometimes. COPD is usually considered a persistent disease. This means that symptoms may appear to some degree all the time. Periods between asthma attacks may last days, weeks, months, or even years. In this way, asthma can seem to go into remission in some people. COPD flare-ups may also be periodic in this way. But, COPD does not go into remission. Asthma usually does not progress over time. COPD is generally considered a progressive disease. But, this progression may be slowed (sometimes significantly) with a proper diagnosis and aggressive treatment. Speaking of diagnosis, both diseases may be confirmed with a test called a pulmonary function test (PFT). The test will show if triggers cause airflow limitation. It can also show if this airflow limitation is reversible (indicating asthma) or not reversible (indicating COPD). Asthma medicines are used to prevent and control asthma symptoms. COPD medicines are used to allay symptoms and slow the progression of the disease. Differences in inflammation There are two types of immune cells that cause airway inflammation: eosinophils and neutrophils. Both may be present in asthma and COPD. But, asthmatic inflammation is usually associated with eosinophils and COPD inflammation is usually associated with neutrophils.3,4 Asthmatic inflammation responds well to corticosteroids and beta 2 adrenergic bronchodilators like albuterol (Ventolinn, ProAir). COPD inflammation responds less well to corticosteroids (although it may respond to some degree). It may respond to bronchodilators like albuterol. But, some studies show it responds better to muscarinic antagonist bronchodilators like ipratropium bromide (Atrovent) and tiotropium bromide (Spiriva). Asthma inflammation makes airways hypersensitive (twitchy) to asthma triggers. Exposure to triggers makes this inflammation worse. This is what causes asthma symptoms and asthma attacks. Hyperactive airways may cause some COPD flare-ups. But, there are various other components of COPD that may also cause flare-ups.3 Prevention and control Therefore, asthma can be prevented and controlled with a daily regimen of inhaled steroids and long-acting bronchodilators. Similar medicines can allay symptoms and slow the progression of COPD. Asthma attacks can be reversed using bronchodilators. Persistent attacks can be reversed with small doses of systemic corticosteroids. COPD flare-ups may be partially reversed with bronchodilators and systemic corticosteroids. They both respond to inhaler and nebulizer medications. These include bronchodilators and corticosteroids. Asthma generally does not require equipment other than inhalers and nebulizers. COPD may require other equipment, such as oxygen supplies, and machines such as CPAP and BiPAP. Genetic differences Asthma tends to be caused by asthma genes. So, it tends to be unpreventable. COPD is usually caused by long-term exposure to noxious substances that are inhaled. So, it is often considered a preventable disease. There are over 100 genes known to cause asthma. There is only one gene known to cause COPD. This gene may cause a rare form of COPD called alpha-1 antitrypsin deficiency. This is often referred to as genetic COPD. Therefore, most cases of asthma are said to be hereditary or genetic. At the present time, only 5% of people with COPD have genetic COPD. This means they develop it regardless of exposure to noxious substances in the air.2 Asthma can be diagnosed at any time in a person’s life. COPD is usually not diagnosed until after the age of 40 or 45. What to make of this? So, there are many similarities between asthma and COPD. There are also many differences, as shown by this list. [lead_gen showIfLoggedIn="0" campaign="shortcode" source="site" title="Sign up for emails from {{site-name}}:"] Both asthma and COPD can sometimes flare up. This is often referred to as asthma or COPD exacerbations. With asthma, these episodes are usually referred to as asthma attacks. With COPD these are usually referred to as COPD flare-ups. So, here are some differences between asthma attacks and COPD flare-ups. Asthma flare-ups Asthma affects the bronchial airways. These are your smallest airways. A key feature of asthma is these airways are chronically inflamed. This makes them hypersensitive or overly sensitive. This means they are twitchy when exposed to asthma triggers.1,2 So, let’s say you have asthma and your asthma trigger is dust mites. So, you’re cleaning a closet and inhale lots of dust mites. This causes your immune system to respond. A series of chemical reactions occur in response to dust mites. This causes airway inflammation to get worse. So, this worsening airway inflammation irritates airway cells. Smooth muscles are wrapped around these airways. These muscles spasm and constrict to squeeze airways. This is called bronchospasm or bronchoconstriction. This causes airways to become narrow. This obstructs the flow of air through them.2 This worsening inflammation also irritates mucus producing cells and glands. These secrete extra mucus. This mucus can collect in airways to further obstruct them.3 A combination of these effects can make you feel short of breath and have chest tightness. It can make you cough. It can make you wheeze.3 Asthma attacks may be experienced differently from one asthmatic to another. Asthma attacks may also vary in intensity and severity over time. However, a key feature of asthma is that asthma attacks are reversible. This can be accomplished by removing yourself from the trigger, by resting, or by taking asthma medicines.3 Another key feature of asthma is that it’s controllable. This means that asthma attacks can be prevented and made mild and easy to control when they do occur. Good asthma control means breathing should be normal between attacks.4 Most of these attacks can be managed at home. For this reason, asthmatics are encouraged to work with their doctors on creating an asthma management program. This may entail both taking medicines and controlling potential asthma triggers. However, some asthma attacks may be severe and life-threatening and require immediate medical intervention.3,4 Asthmatics are also encouraged to create asthma management plans. These plans list daily to-do's to control symptoms along with what to do when symptoms are felt. This may involve tweaking their asthma management plan. It may also entail seeking medical attention.3,4 COPD flare-ups Bronchial airways in COPD are also chronically inflamed. This inflammation may result in airway scarring. This makes airways chronically narrowed. COPD airways are also replete with extra glands and cells that produce mucus. So, excessive mucus production is also a common feature of COPD. Both of these features may cause people with COPD to experience some symptoms every day.5,6 Airways are generally kept sterile. Excessive mucus production may create a nice breeding ground for respiratory infections. So, this makes people with COPD at an increased risk for developing respiratory infections, such as pneumonia. These infections are one of the main causes of COPD flare-ups.5 Like asthma, their inflamed airway may also be hypersensitive. So, like asthma, bronchospasm may occur in response to triggers such as common allergens, strong smells, cigarette smoke, wood smoke, etc. The likelihood of this happening is increased if the person also has asthma.2 The heart may also be affected by COPD. It may fatigue due to working too hard to pump blood through diseased lungs. This may cause a condition called heart failure. When this happens fluid may back up into the lungs.5 Some people with COPD experience no daily symptoms. Although, many people with COPD experience some symptoms every day. Most of these can be managed at home. COPD flare-ups may be severe and life-threatening, requiring immediate intervention. So patients must be properly educated about flare-ups and what to do when they occur. Like asthmatics, COPD doctors are encouraged to work with their patients on creating COPD management plans. These show what to do daily to manage symptoms. They also help guide actions when new or worsening symptoms appear. Such actions may include tweaking the medicine regimen, calling their doctor, or calling 911. What to make of this? So, both COPD and asthma may flare-up from time to time. The goal of any asthma treatment regimen is to control asthma and prevent asthma attacks. The goal of any COPD treatment regimen is to minimize symptoms and prevent COPD flare-ups. [lead_gen showIfLoggedIn="0" campaign="shortcode" source="site"] ,Earlier I explained how asthma becomes COPD. In this post I would like to explain what the risk factors are for asthma becoming COPD. Here's what to know. A 2004 study showed a definite link between asthma and COPD. Researchers studied 3,000 people for 20 years. They concluded that asthmatics have a 12 times greater risk for developing COPD than non-asthmatics.1,2 COPD is consistent with airflow obstructions that are only partially reversible. This results in persistent airflow limitation. This can make you feel some shortness of breath even on good COPD days. However, despite airway obstructions being irreversible, symptoms can be minimized with proper treatment. Asthma also causes airflow obstructions. However, these are completely or almost completely reversible with time or treatment. This means that asthma can be controlled, meaning that symptoms can be prevented. This can be accomplished with proper treatment. Asthma itself is considered a risk factor for COPD.1 Not all asthmatics will be diagnosed with COPD. In fact, most will not. However, one study found that about 20% of asthmatics had persistent airflow limitation.1 When this happens, asthma may be considered COPD. Other than asthma itself, here are 4 Risk Factors for shifting asthma under the COPD umbrella. Cigarette smoke. This would include both first and second-hand smoke. This is the leading risk factor for asthmatics developing COPD. About 39% of asthma-COPD cases are caused by cigarette smoke.1 Hyper-responsive airways. These are asthmatics airways that are very sensitive (twitchy) to asthma triggers. This may happen with the development of airway remodeling and scarring. This is the second greatest risk factor for asthmatics developing COPD. About 15% of asthma-COPD cases are caused by hyper-responsive airways.1 Poor lung growth in children with asthma. This may be due to childhood asthma. Asthma in childhood may cause a person to experience a lung function deficit that may persist into adulthood. When this happens it may increase the likelihood of an eventual diagnosis of COPD. Likewise, children with more severe asthma, and children with asthma and another similar condition (such as allergic rhinitis), were the most likely to have a decline in lung function.1,4-5 Severe asthma. Today, it is understood that 5-10% of asthmatics have severe asthma. This is asthma that continues to be poorly controlled despite adherence to an asthma treatment regimen. One study showed that 40% of children with severe asthma were diagnosed with COPD in adulthood. In comparison, only 8% of children with intermittent asthma, or children with no asthma, were diagnosed with COPD in adulthood. So, there appears to be a possible link between asthma severity and an eventual diagnosis of COPD. One probably reason that severe asthma may lead to COPD is damage to airways due to repeated asthma attacks. This may led to airway remodeling that makes airways abnormally narrow, similar to COPD. This may cause persistent airflow limitation, resulting in a diagnosis of COPD.5-7 What to make of this? Keep in mind that asthma is not emphysema in that it does not cause loss of lung tissue. Also, keep in mind that asthma is not chronic bronchitis. However, airway remodeling may result from the above risk factors. And this remodeling may make airways chronically narrow. It is this that may cause persistent airflow limitation that fits the definition of COPD. Only when this happens does asthma fit under the umbrella term COPD. Some experts may diagnose this as a duo diagnosis of asthma and COPD. Others may lump it under the term Asthma/ COPD Overlap Syndrome (ACOS). [lead_gen showIfLoggedIn="0" campaign="shortcode_posts" source="site"] ,Researchers now understand that about 11% of asthmatics also have COPD, and 10-50% of COPDers over the age of 50 also have asthma. When this happens it is generally diagnosed as Asthma/ COPD Overlap Syndrome (ACOS).1-2 Here is all you need to know about this asthma subgroup. What is ACOS? It almost always has an adult onset, being diagnosed after the age of 40. A joint effort by the Global Initiative for Asthma (GINA) and Global Initiative for Chronic Obstructive Lung Disease (GOLD) defines it this way3: “Asthma-COPD overlap syndrome (ACOS) is characterized by persistent airflow limitation with several features usually associated with asthma and several features usually associated with COPD. ACOS is therefore identified by the features that it shares with both asthma and COPD.”3 What is asthma? It’s associated with chronic, underlying airway inflammation that makes airways hypersensitive (twitchy) to asthma triggers. Exposure to asthma triggers causes this underlying inflammation to worsen, causing asthma attacks, the main feature of which is airflow limitation and shortness of breath. Asthma is reversible. What does reversible mean? A key feature of asthma is that it is completely reversible with either time or treatment. Between asthma episodes lung function is usually normal or close to normal. By working with your doctor to obtain good asthma control, asthma attacks can be prevented or made less severe when they do occur. Asthmatics tend to live normal functioning lives between episodes. It can be diagnosed at any time in a person’s life. What is COPD? This is an acronym for chronic obstructive pulmonary disease. You can learn more by checking out our COPD site. It’s associated with inflammation of airways and lung tissue due to years of exposure to airborne irritants and chemicals. It’s usually adult-onset, diagnosed after the age of 40. There are typically two diseases associated with COPD. Emphysema Lung units (alveoli) may lose their elasticity and ability to regain their shape after a full inhalation. When lung tissue is affected, alveoli may expand all the way to the chest wall, creating air spaces called bullae. This may pull or stretch airways, thereby causing them to become chronically narrow. Chronic Bronchitis. Epithelial cells lining airways are damaged. This results in inflammation that causes airway changes (remodeling or lung scarring). This makes airway walls thicker than normal, making airways chronically narrow. What does Not Reversible mean? A key feature of COPD is persistent airflow limitation that is only partially reversible with time or treatment. It may be associated with some degree of persistent (it’s always there) shortness of breath. COPD is also a progressive disease. What does Progressive mean? Another key feature of COPD is that it gradually progresses with time. However, by working with your doctor to get a proper diagnosis and treatment, and developing an effective COPD treatment program specifically tailored for you, the progression of this disease can be slowed so you can live longer and better with it. ACOS is often diagnosed in tandem with Severe Asthma What types of inflammation are involved? Asthma is generally associated with eosinophilic inflammation, and this makes it very responsive to inhaled corticosteroids. While not all people with COPD smoke, one study showed that asthmatics who smoked were increasingly likely to develop COPD, which is generally associated with neutrophilic inflammation, meaning it is not very responsive to inhaled corticosteroids.4-5 The combination of eosinophilic and neutrophilic asthma means they usually also have a diagnosis of severe asthma. Because of the type of inflammation present, it’s also sometimes referred to as “Smoking Induced Neutrophilic asthma." Interestingly, to make matters worse, one study showed that asthmatics who smoked were more sensitive to allergens (dust mites, pollen, etc) than non-smokers. So, this too can impact underlying airway inflammation, making asthma more severe.5 What is Severe Asthma? This is difficult to treat asthma. It’s an asthma subgroup defined as asthma that only responds to the highest doses of corticosteroids. It is sometimes refractory to corticosteroids, meaning it does not respond to them at all, thereby requiring trials of medicines not traditionally used to treat asthma, such as COPD medicines. It’s often defined as asthma that requires two or more medicines to obtain any degree of asthma control.6-7 Because ACOS is associated with permanent airway scarring like COPD, it usually results in a diagnosis of severe asthma. How is ACOS diagnosed? If you are diagnosed with severe asthma, ACOS should be ruled out as a potential cause. This begins by a physical examination and a history. For instance, do you have a chronic cough? Have you ever been exposed to chemicals at work or home? Do you, or have you ever smoked? You may likely be expected to undergo pulmonary function testing, blood tests, sputum tests, x-rays, cat scan, etc.3 What is the treatment? If not already on them, treatment includes inhaled corticosteroids, and sometimes the highest doses. The highest doses are usually indicated because, as studies show, smoking seems to blunt the effects of corticosteroids in those who have a greater than 10 year smoking history. Studies seem to indicate that montelukast (Singulair) and zileuton (Zyflo) may help improve lung function in smokers or former smokers with a blunted response to corticosteroids.4-5, 8 Corticosteroids are often prescribed in tandem with long acting beta adrenergic medicines in combination inhalers like Advair, Symbicort, Dulera, and Breo. Short acting bronchodilators like Albuterol are usually prescribed. A doctor may prescribe COPD medicine like tiotropium (Spiriva) or old asthma medicines like theophylline. Your doctor may also prescribe newer and less proven asthma and COPD medicine. You should also be encouraged to quit smoking, as this has been shown to slow the progression of the disease.5 What does the future have in store for those with ACOS? In the past, those who displayed features of both asthma and COPD were not included in studies, meaning very little was known about ACOS nor how best to treat it. However, thanks to organizations like GINA and GOLD guidelines have been created to guide physicians towards the best strategies for diagnosing and managing ACOS. 3, 2 [lead_gen showIfLoggedIn="0" campaign="shortcode" source="site" title="Sign up for emails from {{site-name}}:"]

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