COPD Made Easy – Revision by Q&As

Chronic obstructive pulmonary disease (COPD) comprises chronic bronchitis and emphysema. It is a commonly encountered disease in exams as well as clinical practice. In this post, COPD has been made easy to revise through questions and answers. This method will help you register important, hard facts of the disease. To take full advantage of this post, read question and try to answer in your head first. Then read the answer. This way the information will be registered easily.

What is chronic obstructive pulmonary disease (COPD)?

COPD is progressive airway obstruction due to abnormalities in distal airways and/or alveoli, with little or no reversibility. It is typically brought on by prolonged smoking or exposure to harmful particles/gases.

What are the risk factors for its development?

Risk factors for the development of COPD include environmental and host factors. Environmental factors include tobacco or cannabis smoking, occupational coal dust exposure, consumption of biomass fuel in confined spaces. Host factors include age more than 40, and genetic factors like α1-antitrypsin deficiency.

What is the most common risk factor globally?

Cigarette smoking is the most common and significant risk factor. Amount and duration of smoking both are important. COPD usually develops with 10 or more pack years of smoking in susceptible individuals. (1 pack year=20 cigarettes daily per year)

Which diseases are included in COPD?

Two phenotypes included in COPD are:

  1. Chronic bronchitis
  2. Emphysema

What is chronic bronchitis and how does it cause COPD?

Chronic bronchitis is defined clinically as cough and sputum on most days for at least 3 consecutive months in each of 2 consecutive years.

Chronic bronchitis develops due to chronic inflammation of distal airways caused by smoking or pollutants. There is hyperplasia of goblets cells and submucosal glands resulting in increased mucus production. In addition to increased mucus production, its clearance by the muco-ciliary cells of the airways is also impaired. This results in narrowing of these airways and air trapping.

Productive cough is the predominant symptom.

What is emphysema and how does it cause COPD?

Emphysema is defined histologically as enlarged airspaces distal to terminal bronchioles, accompanied by destruction of alveolar walls without fibrosis.

In emphysema, since there is destruction of alveolar walls, elastic recoil in expiratory phase is affected. With progressive damage, more and more alveolar sacs are affected, complete ventilation cannot be achieved and patient breathes on higher lung volumes. Patient has to use accessory muscles to do expire adequately. During this process, intrathoracic pressure exceeds airway pressure, and small airways collapses during expiration. This leads to air trapping.

Furthermore, since there is destruction of alveolar walls, gas exchange surface area is greatly reduced for adequate oxygenation. This results in hypoxemia.

Breathlessness is a predominant symptom of emphysema.

What is ‘pink puffers’ and ‘blue bloaters?

Traditionally, emphysema patients are called pink puffers and chronic bronchitis as blue bloaters.

Emphysema patients are mainly having alveolar wall destruction which results in small airway collapse during expiration and air trapping. Furthermore, surface area become less for gas exchange. These patients are hypoxemic and more breathless.

Chronic bronchitis patient has problem with air way inflammation resulting in increased mucus production, airway blockade and cough. Chronic bronchitis patients are hypercapnic and with passage of time respiratory center adapts to raised PaCO2 in blood. These patients are little cyanosed.

Pink puffer and blue bloater terms are obsolete now and are likely represent ends of a spectrum.

What are the pertinent clinical features of COPD?

Cough and sputum production is the predominant symptom in chronic bronchitis, while breathlessness in emphysema. Moreover, weight loss is common in emphysema while headaches and pedal oedema are common in chronic bronchitis.

History of tobacco/cannabis smoking, environmental pollutants/occupational dust exposure, use of biomass fuel for cooking at home (in developing/poor countries) is important.

What are the signs in COPD?

Patient may have any combination of emphysema and chronic bronchitis, so signs are not limited to either group and patient may have combination of signs.

Chronic bronchitis: cyanosis, wheeze, weight gain, +/- peripheral oedema.

Emphysema: accessory muscle use, pursed lip breathing, barrel-shaped chest, reduced crico-sternal distance (<3cm), reduced chest expansion, resonant or hyper-resonant percussion note, quiet breath sounds (e.g., over bullae), minimal wheezing.

Signs of cor-pulmonale.

How is COPD diagnosed?

Pertinent history of symptoms, presence of risk factors and demonstration of airway obstruction during spirometry (reduced FEV1/FVC < 0.7) without reversibility is diagnostic of COPD.

Which tests, other than spirometry, can be done in COPD patients and what they will show?

Lung volumes (Helium dilution technique or body plethysmography in severe cases): There is evidence of air trapping in emphysema as evidenced by increased total lung capacity (TLC) and residual volume (RV). There is reduced gas exchange as well, demonstrated by reduced diffusion capacity of CO (DLCO).

Radiology

Chest x-ray – Hyperinflation, flat hemidiaphragms, large central pulmonary arteries, reduced peripheral vascular markings, bullae. It excludes alternate diagnoses like heart failure.

HRCT chest – Bronchial wall thickening, scarring, air space enlargement, bullae.

Complete blood count (CBC) – Polycythemia may be present. CBC exclude anemia as cause of dyspnea.

ECG – Right atrial and ventricular hypertrophy if cor-pulmonale has developed.

Arterial blood gases (ABGs) – hypoxemia (reduced PaO2) with or without hypercapnia (PaCO2)

α1- antitrypsin – patients with pan acinar emphysema, especially in young and non-smokers, should be tested for α1-antitrypsin deficiency.

Exercise test – provides an objective assessment of exercise tolerance.

What are different types of emphysema?

There are four types of emphysema seen on imaging (CT scan). First three are not associated with fibrosis.

  1. Centrilobular or centriacinar – it affects the center of a pulmonary lobule, the area around the terminal bronchiole, and the first respiratory bronchiole. Centrilobular emphysema is the most common type usually associated with smoking, and with chronic bronchitis. Upper lobes of lungs are usually affected.
  2. Panlobular or panacinar – it affects all of the alveoli in a lobule and can involve the whole lung or mainly the lower lobes. This type is associated with α1-antitrypsin deficiency.
  3. Paraseptal or distal acinar emphysema relates to emphysematous change next to a pleural surface, or to a fissure. Cystic spaces (blebs or bullae) form beneath the pleura. This type of emphysema is not associated with airflow obstruction.
    When subpleural bullae are significant, the emphysema is called bullous emphysema. Bullae can become extensive and combine to form giant bullae. These may be large enough to compress adjacent lung parenchyma, and cause displacement. The emphysema is now termed giant bullous emphysema, more commonly called vanishing lung syndrome due to the compressed parenchyma. Bleb or bulla may sometimes rupture causing pneumothorax.
  4. Paracicatricial or irregular emphysema – it involves acinus irregularly and is seen next to areas of fibrosis as large spaces. The scarring is most often a result of silicosis, granulomatous infection/tuberculosis, or pulmonary infarction. It can be difficult to differentiate from the honeycombing of pulmonary fibrosis.

What are the complications of COPD?

Severity is assessed by spirometry. According to Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2020 spirometry classification, COPD can be categorized into 4 categories, based on the post-bronchodilator FEV1 % predicted.

FEV1 > 80 %        –             Stage I – mild

FEV1 50 -79 %    –             Stage II – moderate

FEV1 30 – 49 %   –             Stage III – severe

FEV1 <30 %         –             Stage IV – very severe

How is the severity of COPD assessed?

Complications of COPD include:

Acute exacerbations

Infections

Polycythemia

Respiratory failure

Cor pulmonale

Pneumothorax

Lung carcinoma

What are the principles of COPD management?

Smoking cessation

Reduce exposure to noxious particles and gases.

Exercise

Dietary improvement

Bronchodilators

Short-acting bronchodilators, short acting β2-agonists (SABA) like Salbutamol, and short-acting muscarinic-antagonists (SAMA) Ipratropium bromide, are used as relievers.

Long-acting β2-agonists (LABA) like Formoterol, and long-acting muscarinic-antagonists (LAMA) like Tiotropium, are available in single agent or combination inhalers for use in chronic stable COPD.

Combined inhaled corticosteroids (ICS) and bronchodilators are also available for those with frequent exacerbations and/or persistent breathlessness.

Other therapies:

Roflumilast, a phosphodiesterase-4 inhibitor, improves lung function and reduces moderate to severe exacerbations in patients with severe or very severe COPD.

Azithromycin, 500 mg thrice a week, reduces number of exacerbations.

Vaccination

COPD patients should be vaccinated with pneumococcal vaccine and annual influenza vaccination.

Supportive measures

Chest physiotherapy, mucus clearing devices and mucolytic agents (guaifenesin, Erdosteine) assist in sputum expectoration.

What are indications for Long-term oxygen therapy (LTOT)?

LTOT, or domiciliary oxygen, shall be considered in COPD complicated by severe hypoxemia (arterial PaO2 < 55 mmHg), or in those with PaO2 < 60 mmHg along with polycythemia, pulmonary hypertension or peripheral edema. The values should be stable on 2 occasions > 3 weeks apart.

Oxygen given for 15 hours/day with aim to increase PaO2 to at least 60 mmHg or SaO2 >90% improves symptoms and survival.

What are indications for use of non-invasive ventilation (NIV) in COPD?

In patients with hypercapnia, home non-invasive ventilation (NIV) improves quality of life.

What is the important associated risk in emphysema patients?

Osteoporosis. Prevention of osteoporosis, in low weight emphysema patients and those who receive repeated courses of steroid during exacerbations, shall be considered for Bisphosphonates.

What is the ABCD in management of COPD exacerbation?

This acronym stands for antibiotics, bronchodilators, corticosteroids and diuretics. The management of acute exacerbation shall include ABC and if there is fluid retention, diuretic as well.

However, the management is not limited to these but shall also include controlled oxygen delivery to maintain paO2 above 60 mmHg and SaO2 88 – 92 % without worsening acidosis.

In those with worsening acidosis, NIV or invasive ventilation shall be considered on case-to-case basis.

What surgical interventions can be done in COPD patients?

Bullectomy, can be done for large bullae that compress surrounding normal lung tissue.

Lung volume reduction surgery (LVRS) is beneficial in patients with predominantly upper lobe emphysema, preserved gas transfer and no evidence of pulmonary hypertension. It reduces hyperinflation and reduce breathing work.

Dr Abu-Ahmed
Dr Abu-Ahmed

Dr Abu Ahmed, an Internist & Graphic Designer, has brought this website to help Medical Students in the subject of Internal Medicine.

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