B2 W2 - Pathophysiology and Clinical Aspects of Chronic Obstructive Pulmonary Disease (COPD) Flashcards
What is COPD?
COPD, or Chronic Obstructive Pulmonary Disease, is an umbrella term that refers to:
- chronic
- mostly irreversible,
- obstructive
airway changes.
What conditions are included under the umbrella term COPD?
- Chronic bronchitis
- Emphysema
- Some older patients with chronic asthma and asthma-COPD overlap syndrome (“ACOS”).
What is the most common cause of COPD?
Smoking is overwhelmingly the most common cause of COPD.
What is the difference between chronic bronchitis and emphysema?
- Chronic bronchitis is a disease of the larger airways (bronchus, larger bronchioles)
- Emphysema affects the smaller airways (smaller bronchioles, alveoli).
What are the symptoms of chronic bronchitis?
Chronic bronchitis typically causes a chronic, productive cough due to inflammation, mucus gland hypertrophy & hyperplasia, and hypersecretion of mucus in the larger airways.
What are the symptoms of emphysema?
**Shortness of breath (dyspnoea) ** due to alveolar wall destruction and air space enlargement, which results in a reduced gas exchange surface area.
What are the reversible causes of airflow obstruction in COPD?
- Bronchoconstriction (Smooth muscle contraction)
- Inflammation
- Mucus plugging.
What are the irreversible causes of airflow obstruction in COPD?
- Airway remodelling (Chronic Bronchitus)
- Alveolar Wall destruction - loss of lung elasticity (Emphysema)
What are the common symptoms of COPD?
Patients with COPD most commonly present with
- a productive cough (sputum)
- wheeze
- breathlessness (dyspnoea)
- frequent infective exacerbations with purulent sputum.
What are the common signs of COPD?
- Difficulty Completing Sentences
- High Respiratory Rate (Tachypnea)
- High Heart Rate (Tachycardia)
- Audible Wheeze
- Cyanosis
- Barrel Chest
- Use of Accessory Muscles
- Oedema
What is the key investigation for diagnosing COPD?
Spirometry is the key investigation for diagnosing patients with COPD.
What spirometry result confirms a diagnosis of COPD?
A diagnosis of COPD requires a reduced FEV1:FVC ratio below 0.7.
What other investigations can be used in the diagnosis of COPD?
- Chest X-ray
- Arterial blood gas
- Haemoglobin.
What is the most important aspect of care for someone with COPD?
Stopping smoking is by far the most important aspect of care for someone with COPD.
What is the overarching principle of treatment for COPD?
The overarching principle of treatment for COPD is that most treatments are symptomatic; they may improve symptoms, but rarely do much to improve the underlying condition.
Name some classes of drugs commonly used in the management of COPD.
- Bronchodilators
- Anti-Inflammatory Agents
- Combination therapies
- Oral theophylline
- Mucolytic agents.
Besides medication, what other aspects of chronic COPD care can be considered?
In addition to medication, aspects of chronic COPD care include
* smoking cessation
* education
* self-management strategies
* action plans
* immunisation
* pulmonary rehabilitation & exercise
* nutrition & weight management
* long-term oxygen therapy
* home nebulisation
* psychological issues,
* risk reduction from other cardiac & respiratory diseases
* social & occupational therapy support
* end-of-life care.
How are acute exacerbations of COPD managed in the community setting?
increasing the use of inhalers/nebulisers, corticosteroids, and antibiotics.
How are acute exacerbations of COPD managed in the hospital setting?
Management of acute exacerbations of COPD in the hospital setting includes:
- nebulisers
- oxygen
- IV aminophylline
- IV antibiotics
- IV steroids
- chest physiotherapy
- ITU/assisted ventilation.
What are the key differences between the pathophysiology of asthma and COPD?
- The type of inflammation
- The cells involved
- The reversibility of airflow obstruction
- The structural changes in the airways.
What percentage of older smokers have COPD changes in their lungs?
Around 50% of older smokers (those who have smoked for more than 20 years) have COPD changes present in their lungs.
Besides smoking, what other factors can contribute to the development of COPD?
- Exposure to other pollutants
- α1-antitrypsin deficiency.
How should chronic bronchitis and emphysema be viewed in relation to COPD?
It is better to think of an individual with COPD as being on a spectrum of chronic bronchitis and emphysema, with most people having a combination of both conditions to varying degrees.
What are the specific inflammatory and structural changes seen in chronic bronchitis?
Chronic bronchitis involves:
- Squamous metaplasia of the epithelium
- Goblet cell and submucosal gland hyperplasia
- Infiltration of the airway wall with macrophages and CD8+ T-lymphocytes,
- Neutrophils in the airway lumen and around submucosal glands
- Peribronchial fibrosis
- Potential increase in airway smooth muscle
How can medication be used to target reversible causes of airflow obstruction in COPD?
Medications can be used to:
- Relax smooth muscle (e.g., bronchodilators)
- Reduce inflammation (e.g., corticosteroids)
- Thin mucus (e.g., mucolytics)
to improve airflow obstruction.
Historically, what terms were used to describe patients at opposite ends of the COPD spectrum, and why are these terms no longer considered appropriate?
- “Pink puffers” and “blue bloaters” were historically used to describe patients with predominantly emphysematous changes and predominantly chronic bronchitis changes, respectively.
- However, these terms are outdated and inappropriate because most patients have a mix of both conditions, and they reinforce stereotypes that are not always accurate.
In what specific situation are arterial blood gases used in COPD assessment?
During acute exacerbations of COPD to help guide oxygen therapy.
Why is a chest X-ray important in the initial assessment of suspected COPD?
A chest X-ray is crucial to rule out lung cancer, which is important because patients with suspected COPD often have a significant smoking history and are therefore at higher risk of lung cancer.
What are the key differences between the clinical presentation of asthma and COPD?
- Asthma typically presents in childhood with intermittent symptoms, a good response to bronchodilators, normal spirometry between exacerbations, and no smoking history.
- COPD typically presents in older adults with chronic symptoms, a less dramatic response to bronchodilators, persistently abnormal spirometry, and often a history of smoking.
What are the reasons for the increase in COPD deaths globally between 2000 and 2016?
There are several contributing factors.
- Deaths from lower respiratory infections have significantly decreased due to better treatments; however, smoking rates have increased in Asia and Africa.
- Additionally, pollution continues to be a problem in some areas.
- Finally, COPD is often underdiagnosed, especially in healthcare systems where infectious diseases are a more immediate concern.
Why don’t all smokers develop COPD?
- Only 10-20% of smokers develop clinically significant COPD.
- This suggests that genetic and/or epigenetic factors might influence a person’s susceptibility to the harmful effects of cigarette smoke.
What does the FEV1:FVC ratio reveal about lung function and how is it relevant to COPD?
- A reduced FEV1:FVC ratio means that a person, compared to someone with the same lung capacity (FVC), can exhale less air in one second (FEV1).
- This points towards an obstructive airway problem, a key characteristic of COPD.
- This is different from restrictive lung diseases, like pulmonary fibrosis, where lung capacity itself is reduced.
How does smoking cessation impact life expectancy in COPD patients?
- Stopping smoking is the single most important factor in improving life expectancy for individuals with COPD, often by several years.
- Research by Fletcher & Peto from the 1970s showed that while FEV1 naturally declines with age, the decline is much faster in smokers after the age of 45-50.
- However, quitting smoking at any point can improve a patient’s prognosis.
What is asthma-COPD overlap syndrome (ACOS)?
- ACOS refers to patients who have features of both asthma and COPD.
- These patients are often older adults with a history of asthma who develop fixed airflow obstruction, similar to COPD.
How does the presence of lymphoid follicles differ in severe COPD compared to asthma?
- In severe COPD, lymphoid follicles are present in the airway walls.
- This feature is not typically seen in asthma.
Apart from smoking cessation, what other lifestyle interventions are important in COPD management?
Other important lifestyle interventions include:
- Education
- Self-management strategies
- Action plans
- Immunisation (particularly against influenza and pneumonia)
- Pulmonary rehabilitation and exercise
- Optimising nutrition and weight management.
When are oral corticosteroids like prednisolone used in COPD management?
In the management of acute exacerbations of COPD, particularly in the community setting.
What is the role of chest physiotherapy in the management of acute COPD exacerbations?
- Chest physiotherapy is employed in hospital settings during acute exacerbations of COPD.
- It helps to clear mucus from the airways and improve lung function.
What are the differences in the typical inflammatory cells involved in asthma and COPD?
- Asthma is characterized by eosinophils and mast cells as the primary inflammatory cells.
- In contrast, COPD typically involves neutrophils, macrophages, and CD8+ T lymphocytes.
What are the differences in the reversibility of airflow obstruction in asthma and COPD?
- Airflow obstruction in asthma is largely reversible with bronchodilators.
- However, airflow obstruction in COPD is partially reversible at best, as there is significant structural damage to the airways and lung parenchyma.
Besides bronchodilators, what other classes of drugs are commonly prescribed for COPD?
- Inhaled corticosteroids
- Oral theophylline (only when other bronchodilators are ineffective or inappropriate)
- Mucolytic agents.
In which specific cases is weight loss a common symptom in COPD?
In advanced COPD, particularly in those with a predominant emphysema phenotype, weight loss can occur due to the high energy expenditure required for breathing and the loss of appetite.
Explain the pathophysiolgy behind dyspnea (breathlessness) in COPD.
- This is primarily due to the impaired gas exchange in emphysema and the increased work of breathing caused by airflow obstruction.
- It can occur with exertion or even at rest in severe cases.
What is wheezing and explain ir’s pathophysiolgy in COPD.
- Wheezing is a high-pitched whistling sound that occurs during breathing, usually on exhalation.
- It is caused by narrowed airways and airflow obstruction, a hallmark of both chronic bronchitis and emphysema.
What is cor pulmonale?
Right-sided heart failure
