Chronic obstructive pulmonary disease

Last updated: July 22, 2022

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Chronic obstructive pulmonary disease (COPD) is a lung disease characterized by airway obstruction due to inflammation of the small airways. It is caused predominantly by inhaled toxins, especially via smoking, but air pollution and recurrent respiratory infections can also cause COPD. Some individuals are genetically predisposed to COPD, particularly those with α1-antitrypsin deficiency (AATD). COPD begins with chronic airway inflammation that usually progresses to emphysema, a condition that is characterized by irreversible bronchial narrowing and alveolar hyperinflation. These changes cause a loss of diffusion area, which can lead to inadequate oxygen absorption and CO2 release, resulting in hypoxemia and hypercapnia. Most affected individuals present with a combination of dyspnea and chronic cough with expectoration. In later stages, COPD may manifest with more severe symptoms such as tachypnea, tachycardia, and cyanosis. Diagnosis is primarily based on clinical presentation and lung function tests, which typically show a decreased ratio of forced expiratory volume (FEV) to forced vital capacity (FVC). Imaging studies, such as chest x-ray, are helpful in assessing disease severity and the extent of possible complications, but they are not required to confirm the diagnosis. ABG and pulse oximetry are useful for quickly assessing the patient's O2 status. All COPD patients should be staged according to the staging system of the Global Initiative for Chronic Obstructive Lung Disease (GOLD), which considers a variety of factors (e.g., exacerbations, symptom severity, FEV1). Treatment options depend on the GOLD group and mainly consist of short- and long-acting bronchodilators (beta-agonists and parasympatholytics) and glucocorticoids. Individuals with advanced disease may benefit from nonpharmacological treatment with oxygen supplementation and/or noninvasive ventilation. COPD can cause complications such as pulmonary hypertension or respiratory failure. The most significant complication is acute exacerbation of COPD (See AECOPD).

  • COPD is a chronic pulmonary disease characterized by persistent respiratory symptoms and airflow limitation (postbronchodilator FEV1/FVC < 0.70), which is caused by a mixture of small airway obstruction and parenchymal destruction [1]
  • COPD was formerly subdivided into chronic bronchitis and emphysema. These terms are still widely used to describe patient findings and found as subclasses of COPD in outdated literature. [2]
    • Chronic bronchitis: productive cough (cough with expectoration) for at least 3 months each year for 2 consecutive years
    • Emphysema: permanent dilatation of pulmonary air spaces distal to the terminal bronchioles, caused by the destruction of the alveolar walls and the pulmonary capillaries required for gas exchange

Epidemiological data refers to the US, unless otherwise specified.

Exogenous factors

  • Tobacco use (90% of cases) ; [2]
    • Smoking is the major risk factor for COPD, but those who have quit ≥ 10 years ago are not at increased risk. [6]
    • Passive smoking
  • Exposure to air pollution or fine dusts [7]
    • Nonorganic dust: such as industrial bronchitis in coal miners [8]
    • Organic dust: incidence of COPD in areas where biomass fuel (e.g., wood, animal dung) is regularly burned indoors

Endogenous factors

Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification

  • A system that combines spirometric classification, symptom assessment, and history of exacerbations to determine the impact of COPD on a patient's health status.
  • Grade and groups are calculated separately
  • GOLD spirometric grades 1–4
    • Assessed using spirometry at the time of diagnosis and then annually to track any decline in FEV1
    • Inform the prognosis of a patient
  • GOLD Groups A–D
    • Calculated based on the history of exacerbations and severity of symptoms
    • Used to guide management

GOLD grades inform the prognosis of a patient; GOLD groups guide management.

GOLD spirometric grades [1]

GOLD classification of severity of airflow limitation (GOLD report 2022) [1]
Grade Postbronchodilator FEV1% of the predicted value
GOLD 1: mild

≥ 80%

GOLD 2: moderate

50–79%

GOLD 3: severe

30–49%

GOLD 4: very severe

< 30%

Cutoff points between GOLD spirometric grades according to the FEV1%: 30 + 50 = 80

GOLD spirometric grades 1–4 inform the prognosis but correlate weakly with symptoms and functional impairment. [1]

GOLD groups A–D [1]

ABCD group assessment (GOLD report 2022) [1]
Exacerbations in the past year

Severity of symptoms

mMRC dyspnea scale CAT score
COPD group A
  • 0
  • Or 1 not leading to hospital admission
  • 0–1
  • 0–9
COPD group B
  • ≥ 2
  • ≥ 10
COPD group C
  • ≥ 2
  • Or ≥ 1 leading to hospital admission
  • 0–1
  • 0–9
COPD group D
  • ≥ 2
  • ≥ 10

Emphysema subtypes

Emphysema is characterized by the destruction of lung parenchyma and is often seen in patients with advanced pulmonary disease. The presence of emphysema does not necessarily correlate with spirometric findings. Emphysema can be divided into the following subtypes: [1][11]

Smoke rises up:” Centriacinar emphysema is associated with smoking and primarily involves the upper lobes of the lungs.

COPD is characterized by chronic airway inflammation and tissue destruction. [2][12]

Chronic inflammation

It results from significant exposure to noxious stimuli, increased oxidative stress (most commonly due to cigarette smoke) as well as by increased release of reactive oxygen species by inflammatory cells.

Tissue destruction [14]

Symptoms are minimal or nonspecific until the disease reaches an advanced stage.

Presenting findings [2]

  • Chronic cough with expectoration (expectoration typically occurs in the morning)
  • Dyspnea and tachypnea
    • Initial stages: only on exertion
    • Advanced stages: continuously
  • Pursed lip breathing
    • The patient breathes in through the nose and breathes out slowly through pursed lips.
    • This style of breathing increases airway pressure and prevents bronchial collapse during the last phase of expiration.
    • More commonly seen in patients with emphysema
  • Prolonged expiratory phase, end-expiratory wheezing, crackles, muffled breath sounds, and/or coarse rhonchi on auscultation
  • Cyanosis due to hypoxemia
  • Tachycardia

Features of advanced COPD [15]

Nail clubbing is not a finding specific to COPD; its presence usually suggests comorbidities such as bronchiectasis, pulmonary fibrosis, or lung cancer.

Pink puffer and blue bloater [15]

According to their clinical appearance, patients with COPD are often categorized as either “Pink Puffer” or “Blue Bloater”.

Pink puffer vs. blue bloater
Pink Puffer Blue Bloater
Main pathomechanism
Clinical features
  • Noncyanotic
  • Cachectic
  • Pursed-lip breathing
  • Mild cough
PaO2
  • Slightly reduced
  • Markedly reduced
PaCO2

Features of COPD due to AATD

  • Age of onset is generally younger (< 60 years)
  • Also, often have hepatic signs and symptoms (jaundice) related to hepatitis or cirrhosis

Approach [1]

Pulmonary function tests [17]

Spirometry and body plethysmography [1][17]

FEV1 should be reassessed annually in patients with COPD. Screening for COPD using spirometry in patients without symptoms is not generally recommended. [18]

“A COP with low FEVer:” FEV1 for COPD patients.

Postbronchodilator test [19][20]

  • Used to assess the reversibility of bronchoconstriction
    • Change in FEV1 < 12%: irreversible bronchoconstriction [20]
    • Change in FEV1 > 12%: reversible bronchoconstriction [20]
  • The degree of reversibility alone cannot reliably distinguish between the diagnosis of asthma vs. COPD. [1]

Routine studies

Additional studies [1][17]

The following tests are not required for a diagnosis. If performed, they may show typical findings.

The differential diagnoses listed here are not exhaustive.

Management of acute COPD exacerbation is discussed in AECOPD.

Approach [1]

  • Communicate treatment goals, including:
    • Symptom control
    • Reduction of frequency and severity of exacerbations
    • Improvement in quality of life
  • Counsel all patients on supportive measures, including lifestyle modifications and recommended vaccinations.
  • Choose initial medication based on the patient's GOLD group (A–D).
  • Follow-up treatment: Assess the adequacy of symptom control.
    • Continue initial treatment if the response is adequate.
    • If not, adjust medications based on the severity of dyspnea and history of exacerbations.
    • De-escalate treatment if there are adverse effects and/or a lack of clinical benefit.
  • In patients with chronic respiratory failure, consider:

Patient education and training on inhaler techniques are central to improving self-management skills, the ability to cope with illness, and health status. Make sure that instructions are provided and proper technique is demonstrated when prescribing an inhaler, and that inhaler technique is observed at each visit. [1]

Supportive measures

Supportive measures for COPD [1]
Recommendations
Lifestyle modifications
Recommended immunizations in COPD
Management of comorbidities
Pulmonary rehabilitation
  • Appropriate for:
    • All patients with COPD groups B–D at the time of diagnosis
    • Any patient with symptoms or exacerbations despite appropriate treatment
  • Includes respiratory physiotherapy and patient education

Cessation of tobacco use is the single most effective step to slow the decline in lung function in patients with COPD.

Initial treatment

Factors that influence the choice of initial medications include GOLD group, comorbidities, patient preferences, adverse drug reactions, cost, and availability.

Initial pharmacological treatment of stable COPD [1]

Recommended treatment

(DPI: dry powdered inhaler; MDI: metered dose inhaler)

COPD group A
COPD group B
COPD group C
COPD group D

If treatment response is inadequate, consider poor inhaler technique and/or adherence as causes. Common errors include inadequate exhalation prior to inhalation, inadequate inhalation duration, and problems with inspiratory flow.

Bronchodilators are the mainstay of pharmacological treatment of COPD.

Follow-up treatment [1]

  1. Check for persistent symptoms and adjust the regimen based on the predominant trait (dyspnea or exacerbations).
  2. Review the response to treatment escalation; adjust if there is:
  3. If dyspnea persists after adjustments:
    • Consider changing the inhaler or medication within the same class.
    • Evaluate for other causes of dyspnea.
Follow-up treatment in COPD
Predominant trait Initial treatment Follow-up treatment
Persistent dyspnea
Persistent exacerbations
  • Combination therapy

Switching inhalers within a class (e.g., using a different long-acting beta-agonist) in patients with inadequate treatment response may improve management.

Follow-up treatment adjustments are based on treatable traits (dyspnea and frequency of exacerbations) and are made irrespective of the patient's GOLD group (A–D) before treatment initiation. [1]

Inhaled corticosteroids [1]

  • General principles
  • Factors that strongly support initiation of ICS
    • Eosinophil count ≥ 300 cells/μL [1]
    • Eosinophil count > 100 cells/μL and either ≥ 2 moderate exacerbations per year or ≥ 1 hospitalization
    • History of, or concomitant, asthma
  • Factors against initiation ICS
  • Indications for stopping ICS [23]
    • Incorrect original indication
    • Insufficient response to the addition of ICS
    • Adverse effects (e.g., pneumonia)

Commonly used agents include budesonide, fluticasone, beclomethasone.

Other drugs

There is insufficient evidence to support treating stable COPD with antitussives, vasodilators, or leukotriene antagonists. [1]

Respiratory support [1]

For patients started on LTOT, check blood gasses frequently (with ABG or VBG) to ensure adequate oxygenation without unintended acidosis and CO2 retention. [1]

LTOT Increases survival in patients with COPD.

Invasive treatment

Palliative measures (e.g., low-dose opiates, fans blowing onto the patient's face, or acupuncture) can be used if distressing breathlessness persists despite optimal medical therapy. [23][25]

We list the most important complications. The selection is not exhaustive.

  • 40–70% of all COPD patients survive the first 5 years after diagnosis. [26]
  • Survival rates vary significantly depending on the severity of the disease. [26]
  • Measures that improve survival
  • COPD is the third most common cause of death worldwide. [27]
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