Asthma and COPD: Diagnosis, Management, and Exacerbations for PLAB 1
This module covers the essential knowledge regarding Asthma and Chronic Obstructive Pulmonary Disease (COPD), focusing on their diagnosis, management strategies, and the critical handling of exacerbations. This is vital for your PLAB 1 preparation, ensuring you can confidently assess and manage patients with these common respiratory conditions.
Understanding Asthma
Asthma is a chronic inflammatory disease of the airways characterized by reversible airflow obstruction and bronchoconstriction. It is often associated with atopy and can be triggered by allergens, irritants, exercise, and infections.
Diagnosing Asthma
Diagnosis is primarily based on a combination of patient history, clinical examination, and objective lung function tests. Key historical features include episodic shortness of breath, wheezing, chest tightness, and cough, particularly at night or early morning, and often triggered by specific factors.
Episodic shortness of breath, wheezing, chest tightness, and cough.
Spirometry is the cornerstone of asthma diagnosis. It measures lung volumes and flow rates. A diagnosis is supported by demonstrating reversible airflow obstruction, typically a significant increase in Forced Expiratory Volume in 1 second (FEV1) after bronchodilator administration (e.g., >12% and 200ml improvement).
Spirometry is a pulmonary function test that measures how much and how quickly you can move air out of your lungs. It involves inhaling deeply and then exhaling forcefully into a device called a spirometer. Key measurements include FEV1 (Forced Expiratory Volume in 1 second) and FVC (Forced Vital Capacity). In asthma, FEV1 is often reduced, and importantly, it improves significantly after inhaling a bronchodilator medication, indicating reversibility of airflow obstruction.
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Managing Asthma
Asthma management aims to achieve and maintain symptom control and prevent exacerbations. This involves a stepwise approach based on symptom severity and exacerbation frequency.
| Step | Controller Medication | Reliever Medication |
|---|---|---|
| 1 (Intermittent) | None (as needed reliever) | Short-acting beta-agonist (SABA) |
| 2 (Mild Persistent) | Low-dose inhaled corticosteroid (ICS) | SABA |
| 3 (Moderate Persistent) | Low-dose ICS + long-acting beta-agonist (LABA) OR medium-dose ICS | SABA |
| 4 (Severe Persistent) | Medium-dose ICS + LABA, consider add-ons (e.g., LAMA, biologics) | SABA |
The cornerstone of long-term asthma control is regular use of inhaled corticosteroids (ICS) to reduce airway inflammation. SABAs are for quick relief of symptoms.
Understanding COPD
COPD is a progressive lung disease characterized by persistent respiratory symptoms and airflow limitation that is not fully reversible. It is primarily caused by long-term exposure to irritants, most commonly cigarette smoke.
Diagnosing COPD
Diagnosis is based on a history of exposure to risk factors (e.g., smoking), characteristic symptoms (chronic cough, sputum production, dyspnea), and confirmed by spirometry.
Long-term exposure to irritants, most commonly cigarette smoke.
Spirometry is essential for diagnosis, showing persistent airflow limitation with a ratio of FEV1 to FVC less than 0.7 (post-bronchodilator). The severity of COPD is often classified using the GOLD staging system, which considers FEV1 and symptom burden.
Managing COPD
Management focuses on reducing symptoms, improving exercise tolerance, preventing exacerbations, and improving health status. Smoking cessation is the most important intervention.
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Pharmacological treatment typically involves bronchodilators (long-acting beta-agonists (LABA) and long-acting muscarinic antagonists (LAMA)) as the first-line therapy. Inhaled corticosteroids (ICS) may be added for patients with frequent exacerbations or features of asthma overlap. Pulmonary rehabilitation and vaccinations (influenza and pneumococcal) are also crucial components of management.
Asthma vs. COPD: Key Differences
| Feature | Asthma | COPD |
|---|---|---|
| Onset | Often childhood/young adulthood | Usually >40 years |
| Symptoms | Episodic, variable | Persistent, progressive |
| Reversibility | Largely reversible | Not fully reversible |
| Primary Pathology | Inflammation, hyperresponsiveness | Chronic bronchitis, emphysema |
| Allergies/Atopy | Common association | Uncommon association |
| Smoking History | Not a primary cause | Major cause |
Managing Exacerbations
Exacerbations are acute events characterized by worsening of the patient's usual symptoms and signs, beyond normal day-to-day variations. Prompt and appropriate management is critical.
Asthma Exacerbations
Management involves increasing the dose of reliever inhalers (SABA), starting or increasing oral corticosteroids, and considering oxygen therapy if hypoxemic. In severe cases, nebulized bronchodilators and hospital admission may be required.
COPD Exacerbations
Management includes bronchodilators (SABA and/or LAMA), oral corticosteroids, and antibiotics if there are signs of bacterial infection (increased sputum purulence, volume, or dyspnea). Oxygen therapy should be administered cautiously to avoid respiratory depression, aiming for a target saturation of 88-92%.
For COPD exacerbations, careful oxygen titration is crucial to prevent hypercapnic respiratory failure.
88-92%
Learning Resources
The official guidelines from GINA provide comprehensive, evidence-based strategies for asthma diagnosis, management, and prevention.
GOLD provides up-to-date recommendations for the management of COPD, including diagnosis, assessment, and treatment strategies.
National Institute for Health and Care Excellence (NICE) guidelines offer practical advice for the diagnosis and management of asthma in the UK.
NICE guidelines for COPD provide quality standards and recommendations for care in the UK healthcare system.
A patient-focused resource that explains asthma in clear terms, covering causes, symptoms, and management.
The British Lung Foundation offers accessible information on COPD, including diagnosis, treatment, and living with the condition.
e-Learning for Healthcare offers modules relevant to respiratory diseases, often tailored for medical professionals preparing for exams like PLAB.
A detailed medical overview of asthma, covering pathophysiology, diagnosis, and treatment from a clinical perspective.
A comprehensive clinical overview of COPD, including its etiology, diagnosis, and management strategies.
A clear and concise video explaining the key differences between asthma and COPD, which is helpful for visual learners.