Similarities and Differences Between Asthma, COPD And Bronchiectasis

Diseases of the airways of the lungs are common and can include asthma, chronic obstructive pulmonary disease (COPD) and bronchiectasis. These diseases affect the airways of the lungs that carry oxygen and other gases into and out of the lungs. They usually cause a narrowing or blockage of the airways. Although these diseases present some common characteristics and symptoms1, they have different clinical outcomes.

Treatment goals vary for each disease state.  COPD therapy is directed primarily to the relief of symptoms and the prevention of disease progression. In asthma, the primary goal of treatment is to control the underlying inflammatory process with the consequent control of symptoms. In bronchiectasis, the primary goal of treatment is to prevent disease progression and improve the quality of life and symptoms.

The differentiation between asthma, chronic obstructive pulmonary disease (COPD) and bronchiectasis in the early stage of disease is extremely important for the adaptation of appropriate treatment and management options of symptoms.

Chart source: Airway disease: similarities and differences between asthma, COPD and bronchiectasis1

What is COPD?

Chronic obstructive pulmonary disease (COPD)2 is a progressive lung disease that causes obstructed airflow from the lungs. Symptoms include breathing difficulty, cough, mucus (sputum) production and wheezing.  People with COPD are also likely to experience episodes called exacerbations, during which their symptoms become worse than usual day-to-day variation and persist for at least several days. It’s caused by long-term exposure to irritating gases or particulate matter, most often from cigarette smoke. COPD is treatable. With proper management, most people with COPD can achieve good symptom control and quality of life, as well as reduced risk of other associated conditions.

What is Asthma?

Asthma is a chronic lung disease3 that intermittently inflames and narrows the airways in the lungs. The inflammation causes the airways to swell, making it harder to move air in and out of your lungs. Asthma causes periods of wheezing, chest tightness, shortness of breath and coughing.  People who have asthma may experience symptoms that range from mild to severe and that may happen rarely or every day. When symptoms get worse, it is called an asthma attack. Asthma affects people of all ages and often starts during childhood. The goal of asthma management is to achieve control with an asthma action plan. An asthma action plan may include monitoring, avoiding triggers, and using medicines.

What is Bronchiectasis?

Bronchiectasis4 is a condition affecting the airways in the lungs that causes cough, increased mucus production, and recurrent lung infections. The symptoms are caused by abnormal widening of the airways of the lung, also known as bronchi. The cells lining the airways become inflamed and swollen. These damaged airways can no longer effectively clear mucus and bacteria from the lung. This can lead to flare-ups of cough, mucus production, and shortness of breath.

Bronchiectasis is caused by one or more infections introduced into the lungs. People with bronchiectasis are more likely to get lung infections. Each lung infection can make the bronchiectasis worse. Therefore, early diagnosis and treatment of bronchiectasis is very important.

 COPD and Bronchiectasis

The prevalence of bronchiectasis is high in patients with moderate-to-severe chronic obstructive pulmonary disease (COPD)5 and it has been associated with exacerbations and bacterial colonization. Some studies6 have reported a high prevalence of bronchiectasis (between 29 and 52%) in patients with moderate-to-severe COPD. It can be easy to mistake one disease for the other. Both diseases have symptoms of dyspnea (shortness of breath), chronic cough, potential for daily sputum production, and airflow obstruction. Investigation for bronchiectasis should be considered in patients with COPD with frequent exacerbations (two or more annually) and a previous positive sputum culture for P. aeruginosa.

COPD is often treated with anti-inflammatory drugs, such as inhaled corticosteroids. However, bronchiectasis often requires an antibacterial approach to stop the vicious cycle of impaired ciliary function leading to bacterial colonization and thick mucus accumulation, leading to inflammation and impairment of airway clearance. Diagnosis of bronchiectasis in COPD patients allows for proper treatment of underlying infection and inflammation.

Asthma and Bronchiectasis

Asthma and bronchiectasis are different conditions that frequently coexist. However, bronchiectasis is increasingly being identified in patients with severe asthma and could contribute to disease severity.  One study found that in patients with severe asthma, the prevalence of bronchiectasis is high and that bronchiectasis is associated with a longer asthma history, greater severity and, more importantly, chronic airflow obstruction. Almost a third of the patients7 with uncontrolled moderate-to-severe asthma had bronchiectasis. The severity of asthma, chronic expectoration, and a history of previous pneumonia can be independent predictive factors for bronchiectasis in subjects with UMSA.

A diagnosis of bronchiectasis in asthma patients could lead to modifications to both therapy and prognosis (as in the case of COPD patients).  In contrast to asthma attacks/exacerbations, bronchiectasis exacerbations require effective antibiotic therapy, ideally guided by sputum culture.

Diagnosing Bronchiectasis

The gold standard for confirming the diagnosis of bronchiectasis is a high-resolution computed tomography (HRCT) scan of the chest, ideally done when the patient is clinically stable. Requesting an HRCT for patients with severe asthma or COPD can help to diagnose overlap of bronchiectasis and evaluate management strategies in order to improve treatment and quality of life.

 Treating Bronchiectasis

The goals of treatment in bronchiectasis are to facilitate airway clearance, suppress bacterial infection and prevent exacerbations. Patients should be made aware of the range of available airway clearance techniques including HFCWO vest therapy, huff coughing, bronchiodilators, hypertonic saline, positive expiratory pressure and exercise. Patient preference and adherence to treatment should be considered when recommending and discussing airway clearance techniques. The frequency and duration of the airway clearance technique should be tailored to the individual and may alter during periods of exacerbation.

REFERENCES

  1. Athanazio, R et al. Airway disease: similarities and differences between asthma, COPD and bronchiectasis. Clinics (2012) 67(11):1335 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3488995/
  2. COPD Foundation: https://www.copdfoundation.org/What-is-COPD/Understanding-COPD/What-is-COPD.aspx
  3. AAAI – American Academy of Allergy, Asthma and Immunology: https://www.aaaai.org/conditions-and-treatments/asthma
  4. American Lung Association: https://www.lung.org/lung-health-and-diseases/lung-disease-lookup/bronchiectasis/
  5. Miguel-Angel Martínez-García, et al. Prognostic Value of Bronchiectasis in Patients with Moderate-to-Severe Chronic Obstructive Pulmonary Disease. Am J Respir Crit Care Med. 2013 Apr 15;187(8):823-31. https://www.ncbi.nlm.nih.gov/pubmed/23392438
  6. Irem S. Patel , et al. Bronchiectasis, Exacerbation Indices, and Inflammation in Chronic Obstructive Pulmonary Disease. Am J Respir Crit Care Med. 2004 Aug 15;170(4):400-7. https://www.atsjournals.org/doi/full/10.1164/rccm.200305-648OC
  7. Padilla-Galo, A., Olveira, C., Fernández de Rota-Garcia, L. et al. Factors associated with bronchiectasis in patients with uncontrolled asthma; the NOPES score: a study in 398 patients. Respir Res 19, 43 (2018) https://respiratory-research.biomedcentral.com/articles/10.1186/s12931-018-0746-7#citeas