The Differences Between COPD and Asthma

Asthma and chronic obstructive pulmonary disease (COPD) are both respiratory diseases involving chronic inflammation that leads to airflow obstruction. While they share similar symptoms, their causes and treatments differ. In some cases, asthma and COPD may overlap in what is termed asthma-COPD overlap syndrome, or ACOS.

Symptoms

Both asthma and COPD may present with these symptoms:

• Chest tightness
• Chronic cough
• Shortness of breath
• Wheezing

However, the frequency and predominating symptoms in asthma and COPD are different. With COPD, you are more likely to experience a morning cough, increased amounts of sputum, and persistent symptoms. If you have asthma, you are more likely to experience episodic symptoms during and/or at night.

Another difference between asthma and COPD is the intermittent symptoms seen with asthma versus the chronic, progressive symptoms seen in COPD. Asthma symptoms are likely to occur after exposure to specific triggers, whereas COPD symptoms occur more regularly.

There are a number of other differences between COPD and asthma as well.

Once you develop COPD, your symptoms will generally be chronic. Over time, with COPD, you are likely to experience symptoms that are not typical for asthma—losing weight, decreased strength, and diminished endurance, functional capacity, and quality of life.

Causes

Both asthma and COPD may be considered inflammatory diseases, but the inflammation comes from different types of white blood cells.

• In the pathophysiology of asthma, inflammation results acutely from the production of eosinophils, a type of white blood cell that increases in the presence of an allergen. This response causes airways to become inflamed and irritable when triggered by an allergen. When this happens it becomes more difficult to move air in and out of your airways, which leads to asthma symptoms.
• In COPD, your lungs become damaged following exposure to certain irritants, most commonly due to chronic cigarette smoking. This chronic exposure and damage lead to airway obstruction and hyperinflation. The pathophysiology of COPD primarily involves the production of neutrophils and macrophages over many years.

Diagnosis

Both conditions are diagnosed via a combination of your history, a physical exam, and diagnostic testing.

Your healthcare provider will likely start by taking a detailed medical and family history and ask you about your symptoms and current lifestyle habits (e.g., smoking).

They will do a physical examination, listening for signs of wheezing, shortness of breath, and cough. They may also look for signs of nasal inflammation that can make asthma symptoms more pronounced.

Diagnostic Tests

Spirometry is a simple, non-invasive breathing test that is often used in the assessment of COPD and asthma. Spirometry is usually performed in a practitioner's office. Your healthcare provider will instruct you on how to breathe into a small device while measuring certain aspects of your lung function such as forced expiratory volume (FEV1), which is the amount of air that can be forcefully exerted from the lungs in one second.

If your healthcare provider thinks you might have COPD, they will also measure your blood oxygen level via non-invasive pulse oximetry and/or an arterial blood gases (ABG) blood test.

Your practitioner may also request that you undergo imaging such as an X-ray or computed tomography (CT) scan, which can identify abnormalities in the lungs and potentially rule out other conditions.

Treatment

Asthma and COPD are treated with different treatments because the cause of inflammation is different. The goals of treatment in asthma and COPD are also different.

• Asthma Treatment Goals: If you have asthma, your healthcare provider will prescribe medications to lower or suppress inflammation.
• COPD Treatment Goals: The goal of COPD treatment is to reduce symptoms and prevent progression of lung damage, while decreasing exacerbations and improving quality of life.

Medications

Some of the same medications are used for the treatment of asthma and COPD, but the "when, why, and how" of these medications may be different. Medications used for the treatment of asthma and COPD may include inhaled steroids, anticholinergics, short-acting bronchodilators (SABAs), and long-acting beta-agonists (LABAs).

Inhaled Steroids

Inhaled steroids, such as Flovent, are advantageous in both asthma and COPD because the medication acts directly in the lung. However, inhaled steroids are used differently in asthma and COPD.

• In asthma, inhaled steroids are typically the first daily medication prescribed, usually after asthma progresses from intermittent to mild persistent asthma.
• In COPD, inhaled steroids are added to the treatment of severe COPD that involves multiple exacerbations.

Anticholinergics

Short-acting anticholinergics, such as Atrovent, are used in the treatment of acute asthma exacerbations, while long-acting anticholinergic Spiriva is prescribed as a controller medication in asthma.

Spiriva is used relatively early in COPD because it has been associated with improvements in lung function, symptoms, and quality of life while decreasing COPD exacerbations and hospitalizations. 

Short-Acting Bronchodilators (SABAs)

In asthma, SABAs are used for the periodic relief of acute symptoms. The need for using a SABA frequently may mean that you have met the criteria for mild persistent asthma—and additional medication will be required.

In contrast, scheduled SABAs are among the first treatments used for COPD.

Long-Acting Beta-Agonists (LABAs)

While LABAs like Serevent may be used for early COPD treatment, these drugs are indicated for the treatment of moderate persistent asthma, not for mild asthma.

Bronchial Thermoplasty

This intervention is used for the treatment of severe persistent asthma that is not well-controlled with inhaled corticosteroids and LABAs. A bronchoscopy is used to apply heat to the airways to decrease their ability to constrict (narrow), such as when exposed to triggers that can lead to an asthma attack.

Surgery

Surgical treatment is not used to manage asthma, and it can be a treatment option in rare cases of COPD. This treatment is generally reserved for people who have has severe lung damage despite medical therapy.

Lung volume reduction surgery (LVRS) can be done to remove severely damaged lung tissue (up to 30% of lung volume) so that the remaining lung tissue can function more efficiently. LVRS is performed with video assistance and is a minimally invasive procedure, although the surgery is significant.

Overlap Syndrome

While asthma and COPD are two separate conditions, some people have features of both conditions and may be diagnosed with overlap syndrome, also known as asthma-chronic obstructive pulmonary disease (ACOS).

Studies have shown that between 10 to 20% of people who have COPD also have asthma. Surprisingly, 1 in 4 people with asthma smoke, and are at risk for COPD like any other smoker.

ACOS causes frequent exacerbations, worse quality of life, and more comorbidities (other diseases or conditions occurring at the same time) than asthma or COPD alone.

Treatment for ACOS primarily consists of symptom management and depends on which condition is more predominant. Medications such as low-dose corticosteroids, LABAs, and long-acting muscarinic agonists may be used along with lifestyle changes.