# Seminar 8: COPD and Asthma ## Year 3: Internal Medicine Clerkship --- ## Learning Objectives By the end of this seminar, students will be able to: 1. Differentiate COPD from asthma clinically and by spirometry 2. Classify COPD severity and apply GOLD guidelines 3. Describe pharmacologic management of stable COPD 4. Manage COPD exacerbations 5. Apply stepwise asthma therapy 6. Recognize and treat acute asthma exacerbations --- ## Seminar Outline ### I. Overview and Differentiation Chronic obstructive pulmonary disease represents a heterogeneous lung condition characterized by chronic respiratory symptoms including dyspnea, cough, and sputum production caused by airway abnormalities and alveolar destruction that result in persistent, often progressive airflow obstruction that is not fully reversible. The disease encompasses two primary pathologic entities that frequently coexist: emphysema, characterized by destruction of alveolar walls and loss of elastic recoil leading to air trapping, and chronic bronchitis, clinically defined as productive cough occurring for at least three months per year for two consecutive years. Cigarette smoking remains the dominant cause of COPD, accounting for approximately 80-90% of cases in developed countries, with disease development typically requiring cumulative exposure of 20 or more pack-years. Additional risk factors include occupational exposures to dusts and chemicals, indoor air pollution from biomass fuel combustion, alpha-1 antitrypsin deficiency, and recurrent childhood respiratory infections that impair lung development. Asthma is a chronic inflammatory airway disease characterized by episodic, reversible bronchoconstriction with variable respiratory symptoms and expiratory airflow limitation that fluctuates over time and in intensity. The hallmark features include airway hyperresponsiveness to various stimuli, mucus hypersecretion, and airway remodeling that can become permanent without adequate treatment. Common triggers include aeroallergens such as dust mites, pet dander, pollen, and mold, as well as respiratory infections, exercise, cold air, emotional stress, and certain medications including NSAIDs and beta-blockers. Unlike COPD, asthma often begins in childhood, is associated with atopy and allergic conditions, and demonstrates significant reversibility of airflow obstruction with bronchodilator administration. The clinical differentiation between COPD and asthma relies on several key distinguishing features that guide diagnosis and treatment selection. COPD typically presents in adults over 40 years old with a significant smoking history, progressive and persistent symptoms, and only partial reversibility on spirometry, while asthma can present at any age, often in childhood, with episodic symptoms that vary in frequency and intensity, and demonstrates significant bronchodilator reversibility defined as improvement in FEV1 of at least 12% and 200 mL. Peripheral blood eosinophilia is more commonly associated with asthma and eosinophilic COPD phenotypes, while neutrophilic airway inflammation predominates in typical smoking-related COPD. Family history of atopy, allergic rhinitis, and eczema supports an asthma diagnosis, whereas the absence of these features with heavy smoking history favors COPD. Asthma-COPD overlap represents a clinical entity present in approximately 15-20% of patients with obstructive lung disease, characterized by features of both conditions occurring in the same individual. These patients demonstrate persistent airflow limitation typical of COPD but also exhibit significant bronchodilator reversibility, eosinophilic inflammation, or a history of atopic disease characteristic of asthma. The overlap syndrome often requires treatment approaches combining elements from both COPD and asthma guidelines, typically including inhaled corticosteroids as a foundation of therapy due to the eosinophilic component. Recognition of this overlap is clinically important because these patients tend to have more frequent exacerbations, worse quality of life, and faster disease progression compared to patients with either condition alone. Panel A: Comparative diagram showing normal bronchiole, asthmatic bronchiole with inflammation and mucus, and COPD bronchiole with fibrosis and emphysematous alveoli. Panel B: Spirometry tracings comparing normal flow-volume loops with obstructive patterns in COPD (flattened expiratory limb) and asthma before and after bronchodilator showing reversibility. Panel C: Venn diagram illustrating the clinical features unique to COPD, unique to asthma, and shared features in the overlap zone. Panel D: Timeline diagram showing typical age of onset, symptom patterns, and disease progression differences between COPD and asthma. --- ### II. COPD Pathophysiology and Diagnosis The pathophysiology of COPD involves a complex interplay of inflammatory processes, proteolytic imbalances, oxidative stress, and abnormal repair mechanisms that lead to progressive structural changes in the airways and lung parenchyma. Chronic inhalation of noxious particles and gases, primarily from cigarette smoke, triggers an abnormal inflammatory response characterized by increased numbers of neutrophils, macrophages, and CD8+ T lymphocytes in the airways and lung tissue. This inflammatory milieu releases proteolytic enzymes including neutrophil elastase and matrix metalloproteinases that overwhelm the protective antiprotease defenses, leading to destruction of elastin fibers and alveolar walls characteristic of emphysema. Simultaneously, chronic inflammation stimulates goblet cell hyperplasia and mucus gland hypertrophy resulting in mucus hypersecretion, while small airway fibrosis and smooth muscle hypertrophy contribute to fixed airway narrowing. Risk factor identification is essential for COPD prevention, early detection, and management optimization. Cigarette smoking remains the single most important risk factor, with 80-90% of COPD cases attributable to tobacco smoke exposure, though only about 20% of smokers develop clinically significant COPD, suggesting genetic susceptibility modifiers. Alpha-1 antitrypsin deficiency, an autosomal codominant condition affecting approximately 1-2% of COPD patients, should be suspected in young patients under 45 years with minimal smoking history, lower lobe predominant emphysema, or associated liver disease, and all COPD patients should be screened at least once. Occupational exposures to organic and inorganic dusts, chemical fumes, and vapors contribute to approximately 10-20% of COPD cases, while indoor air pollution from biomass fuel combustion is a major risk factor in developing countries where wood, charcoal, or dung are used for cooking and heating. Spirometry is the essential diagnostic test for COPD, with the defining criterion being the presence of persistent airflow limitation demonstrated by a post-bronchodilator FEV1/FVC ratio less than 0.70 that is not fully reversible. The severity of airflow obstruction is classified according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) staging system based on post-bronchodilator FEV1 as a percentage of predicted: GOLD 1 (mild) represents FEV1 greater than or equal to 80% predicted, GOLD 2 (moderate) indicates FEV1 50-79% predicted, GOLD 3 (severe) signifies FEV1 30-49% predicted, and GOLD 4 (very severe) defines FEV1 less than 30% predicted. The spirometric assessment should always be performed after administration of a bronchodilator to minimize variability and ensure accurate classification of disease severity. Additional supportive findings may include increased total lung capacity and residual volume indicating air trapping, and reduced diffusing capacity for carbon monoxide in emphysema-predominant disease. The clinical presentation of COPD varies considerably among patients, leading to recognition of distinct phenotypes that may influence treatment approach and prognosis. The classic "pink puffer" phenotype describes patients with emphysema-predominant disease who are typically thin, demonstrate significant dyspnea with pursed-lip breathing, maintain relatively normal oxygenation until late disease, and have minimal sputum production. The "blue bloater" phenotype characterizes chronic bronchitis-predominant patients who present with chronic productive cough, cyanosis, peripheral edema from cor pulmonale, hypoxemia, and hypercapnia but may have relatively preserved exercise tolerance. The frequent exacerbator phenotype, defined as experiencing two or more exacerbations per year or one or more hospitalizations, represents a distinct subset requiring intensified treatment regardless of spirometric severity. Recognition of these phenotypes helps guide individualized therapy selection and predict clinical outcomes. Panel A: Histopathological comparison showing normal alveoli versus emphysematous destruction with enlarged airspaces and loss of septal walls, and normal bronchiole versus chronic bronchitis with goblet cell hyperplasia and mucus accumulation. Panel B: Illustrated protease-antiprotease balance theory showing how cigarette smoke tips the balance toward proteolytic destruction. Panel C: Spirometry interpretation guide showing normal predicted values, obstructive pattern with reduced FEV1/FVC, and GOLD severity staging with corresponding FEV1 percentages. Panel D: Clinical photographs depicting pink puffer phenotype (thin, dyspneic patient with pursed lips) and blue bloater phenotype (obese, cyanotic patient with peripheral edema). --- ### III. COPD Assessment and Classification The GOLD ABCD assessment tool provides a comprehensive framework for evaluating COPD patients beyond spirometric severity alone, integrating symptom burden and exacerbation risk to guide initial pharmacologic therapy selection. Group A encompasses patients with low symptom burden, defined as modified Medical Research Council (mMRC) dyspnea grade 0-1 or COPD Assessment Test (CAT) score less than 10, who have experienced zero or one moderate exacerbation not requiring hospitalization in the past year. Group B includes patients with high symptom burden, indicated by mMRC grade 2 or higher or CAT score 10 or greater, but with similarly low exacerbation risk of zero to one moderate event without hospitalization annually. Group E, representing the highest risk category, includes patients with any symptom level who have experienced two or more moderate exacerbations or one or more exacerbations requiring hospitalization in the preceding year, reflecting the critical importance of exacerbation history in driving treatment intensity. Standardized symptom assessment tools enable objective, reproducible evaluation of disease impact and treatment response in clinical practice. The modified Medical Research Council dyspnea scale grades breathlessness from 0 to 4, with grade 0 indicating dyspnea only with strenuous exercise, grade 1 describing shortness of breath when hurrying on level ground or walking up a slight hill, grade 2 indicating walking slower than age-matched peers due to breathlessness, grade 3 signifying need to stop for breath after walking about 100 meters or a few minutes on level ground, and grade 4 representing too breathless to leave the house or dyspnea when dressing. The COPD Assessment Test is an eight-item questionnaire measuring cough, sputum, chest tightness, breathlessness, activity limitation, confidence leaving home, sleep quality, and energy level, with scores ranging from 0 to 40 and a threshold of 10 or greater indicating high symptom impact. Regular reassessment using these tools helps monitor disease progression and treatment efficacy over time. Exacerbation risk assessment is particularly critical because prior exacerbations represent the strongest predictor of future events, establishing a vicious cycle of inflammation, lung function decline, and recurrent acute episodes. Patients with a history of frequent exacerbations tend to experience accelerated FEV1 decline, worse quality of life, increased mortality, and higher healthcare costs compared to those with stable disease. Additional factors associated with increased exacerbation risk include lower baseline FEV1, chronic bronchitis phenotype with persistent productive cough, gastroesophageal reflux disease, higher blood eosinophil counts which may predict response to inhaled corticosteroids, and presence of bacterial colonization of the lower airways. Identifying high-risk patients allows for treatment intensification and prophylactic strategies including appropriate maintenance medications, vaccinations, and pulmonary rehabilitation. Comprehensive COPD evaluation extends beyond spirometry and symptom assessment to include additional investigations that inform prognosis and guide management decisions. Chest radiography or computed tomography helps exclude alternative diagnoses, characterize emphysema distribution and severity, and identify comorbidities such as lung cancer or bronchiectasis that may influence treatment. Arterial blood gas analysis should be performed in patients with severe airflow limitation with FEV1 less than 50% predicted, evidence of respiratory failure, or right heart failure to assess for chronic hypoxemia and hypercapnia requiring long-term oxygen therapy. The six-minute walk test provides objective assessment of functional exercise capacity, with distance walked correlating with mortality and often used to assess need for supplemental oxygen and response to pulmonary rehabilitation. Alpha-1 antitrypsin serum level testing should be performed at least once in all COPD patients to identify those who might benefit from augmentation therapy and to enable genetic counseling for family members. Panel A: GOLD ABCD assessment grid showing symptom scores (mMRC, CAT) on the y-axis and exacerbation history on the x-axis, with Groups A, B, and E clearly labeled with their criteria. Panel B: Visual depiction of the mMRC dyspnea scale from grade 0 to 4 with illustrations of corresponding activity limitations. Panel C: Sample COPD Assessment Test questionnaire with scoring interpretation thresholds. Panel D: Exacerbation risk factor diagram showing interconnected factors including prior exacerbations, low FEV1, chronic bronchitis, eosinophilia, and bacterial colonization. --- ### IV. Stable COPD Management Non-pharmacologic interventions form the foundation of COPD management and should be implemented in all patients regardless of disease severity. Smoking cessation is the single most effective intervention for slowing disease progression and reducing mortality, with evidence showing that sustained abstinence leads to decreased rate of FEV1 decline, reduced exacerbation frequency, and improved survival regardless of when cessation occurs during the disease course. Pharmacologic aids for smoking cessation including nicotine replacement therapy, bupropion, and varenicline should be offered to all patients who smoke, with varenicline demonstrating the highest efficacy rates. Pulmonary rehabilitation, a comprehensive program incorporating supervised exercise training, education, and psychosocial support, improves exercise capacity, reduces dyspnea and fatigue, enhances quality of life, and decreases healthcare utilization in patients with persistent symptoms despite optimal pharmacotherapy. Vaccination against influenza annually and pneumococcal disease, COVID-19, and pertussis according to guidelines reduces the risk of respiratory infections that precipitate exacerbations. Initial pharmacotherapy selection is guided by the GOLD ABCD assessment, with treatment intensity matched to symptom burden and exacerbation risk. Patients in Group A with low symptoms and low exacerbation risk should receive a bronchodilator of any class, either short-acting for as-needed use or long-acting for regular maintenance, based on patient preference and response. Group B patients with high symptom burden but low exacerbation risk benefit from long-acting bronchodilator monotherapy, with long-acting muscarinic antagonists (LAMAs) such as tiotropium generally preferred over long-acting beta-agonists (LABAs) due to superior efficacy in preventing exacerbations. Group E patients with high exacerbation risk require dual long-acting bronchodilator therapy with a LAMA plus LABA combination, with consideration of adding an inhaled corticosteroid (ICS) if blood eosinophil counts are 300 cells per microliter or higher, reflecting the role of eosinophilic inflammation in driving exacerbation risk in certain patients. The major medication classes used in COPD include bronchodilators that reduce airflow obstruction and improve symptoms, and anti-inflammatory agents that target specific inflammatory pathways. Short-acting bronchodilators including albuterol, a beta-2 agonist, and ipratropium, an anticholinergic, provide rapid symptom relief and are used as rescue medications and in acute exacerbations. LAMAs including tiotropium, umeclidinium, and glycopyrrolate provide sustained bronchodilation through muscarinic receptor blockade and are particularly effective for reducing exacerbations. LABAs such as salmeterol, formoterol, indacaterol, and olodaterol provide complementary bronchodilation through beta-2 receptor activation and work synergistically with LAMAs. Inhaled corticosteroids reduce airway eosinophilic inflammation but have limited efficacy as monotherapy in COPD and are associated with increased pneumonia risk, so their use should be reserved for patients with elevated eosinophil counts or frequent exacerbations despite optimized bronchodilator therapy. Treatment escalation follows a stepwise approach based on persistent symptoms or exacerbations despite current therapy, while de-escalation may be appropriate when therapy exceeds clinical needs. Patients with persistent dyspnea on LAMA monotherapy should have a LABA added to create dual bronchodilator therapy, which provides greater bronchodilation and symptom improvement than either agent alone. For patients experiencing exacerbations despite LAMA plus LABA combination therapy, escalation depends on blood eosinophil count: if eosinophils are 300 cells per microliter or higher, adding an ICS to create triple therapy is appropriate, while if eosinophils are below 300, adding roflumilast, a phosphodiesterase-4 inhibitor with anti-inflammatory effects, or azithromycin for its immunomodulatory properties should be considered instead. When ICS has been prescribed but provides no demonstrable benefit and eosinophil counts are low, gradual withdrawal may be considered given the risks of pneumonia and other adverse effects. Long-term oxygen therapy is indicated for patients with chronic severe hypoxemia, specifically resting PaO2 of 55 mmHg or less, or PaO2 60 mmHg or less with evidence of cor pulmonale or polycythemia. Panel A: Treatment algorithm flowchart starting with GOLD group classification (A, B, E) and showing initial therapy selection with escalation pathways based on symptoms and exacerbations. Panel B: Medication class comparison table showing drug names, mechanisms, duration of action, and key advantages for SABA, SAMA, LABA, LAMA, and ICS. Panel C: Eosinophil-guided ICS prescribing diagram showing blood eosinophil thresholds and corresponding treatment recommendations. Panel D: Non-pharmacologic intervention summary showing evidence levels for smoking cessation, pulmonary rehabilitation, vaccination, and oxygen therapy. --- ### V. COPD Exacerbation A COPD exacerbation is defined as an acute worsening of respiratory symptoms beyond normal day-to-day variation that leads to a change in medication, representing a critical event in the disease course associated with accelerated lung function decline, decreased quality of life, and increased mortality. The cardinal symptoms of exacerbation include increased dyspnea, increased sputum volume, and increased sputum purulence, with the presence of all three indicating a severe episode likely to benefit from antibiotic therapy. Viral infections, particularly rhinovirus, influenza, and respiratory syncytial virus, trigger 50-70% of exacerbations, while bacterial pathogens including Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis contribute to 30-50% of events, often as secondary infections following viral illness. Environmental factors including air pollution and changes in temperature or humidity can also precipitate exacerbations, and in a substantial proportion of cases no trigger is identified. Assessment of exacerbation severity guides disposition decisions and treatment intensity. Mild exacerbations involve increased symptoms that can be managed with increased short-acting bronchodilators at home without additional medical intervention. Moderate exacerbations require treatment with short-acting bronchodilators plus systemic corticosteroids and potentially antibiotics, managed on an outpatient basis with close follow-up. Severe exacerbations necessitate hospitalization due to significant respiratory distress, severe hypoxemia or hypercapnia, altered mental status, hemodynamic instability, or failure of outpatient management. The clinical evaluation should include vital signs assessment for tachypnea, tachycardia, and hypoxemia, physical examination for accessory muscle use, cyanosis, and altered mental status, pulse oximetry, and when severe disease is suspected, arterial blood gas analysis to evaluate for acute respiratory acidosis indicating hypercapnic respiratory failure. Outpatient management of COPD exacerbations focuses on intensifying bronchodilator therapy, providing systemic corticosteroids to reduce airway inflammation, and administering antibiotics when indicated. Short-acting bronchodilators should be used more frequently, typically albuterol via metered-dose inhaler with spacer or nebulizer every one to four hours as needed, combined with ipratropium if not already using long-acting anticholinergic therapy. Systemic corticosteroids, specifically prednisone 40 mg orally once daily for five days, have been shown to shorten recovery time, improve lung function, and reduce treatment failure without significant benefit from longer courses. Antibiotics are indicated when patients present with increased sputum purulence in addition to increased dyspnea or sputum volume, with appropriate choices including amoxicillin-clavulanate, azithromycin, or a respiratory fluoroquinolone, though the choice should be guided by local resistance patterns and prior culture data. Patients should be reassessed within 48-72 hours if not improving, with follow-up scheduled within one to two weeks for those who respond appropriately. Inpatient management of severe COPD exacerbations follows similar principles with more intensive monitoring and intervention. Nebulized bronchodilators using albuterol combined with ipratropium are administered frequently, typically every four to six hours initially or more often if needed, providing higher drug delivery than metered-dose inhalers in severely dyspneic patients. Systemic corticosteroids are given at similar doses to outpatient management, with prednisone 40 mg daily for five days being equally effective as higher doses or longer courses. Supplemental oxygen should be titrated to achieve oxygen saturation of 88-92%, avoiding excessive oxygenation that may worsen hypercapnia in patients with chronic respiratory failure dependent on hypoxic respiratory drive. Non-invasive ventilation with bilevel positive airway pressure (BiPAP) is indicated for patients with acute hypercapnic respiratory failure, specifically pH less than 7.35 with PaCO2 greater than 45 mmHg, and has been shown to reduce intubation rates, length of stay, and mortality. Invasive mechanical ventilation is reserved for patients with severe acidosis who fail non-invasive ventilation, cardiovascular instability, impaired consciousness precluding NIV, or respiratory arrest. Panel A: COPD exacerbation severity classification comparing mild, moderate, and severe presentations with corresponding symptoms, vital signs, and management location. Panel B: Treatment algorithm flowchart for acute exacerbation showing branching pathways for outpatient versus inpatient management with specific medication regimens. Panel C: Indications for non-invasive ventilation in COPD exacerbation showing ABG criteria and clinical parameters. Panel D: Timeline of exacerbation recovery showing expected improvements in symptoms, peak flow, and quality of life over days to weeks, with markers for when to escalate care if not improving. --- ### VI. Asthma Pathophysiology and Diagnosis The pathophysiology of asthma involves chronic airway inflammation driven primarily by type 2 immune responses, leading to bronchial hyperresponsiveness, reversible airflow obstruction, and, if untreated, progressive airway remodeling. The inflammatory infiltrate in asthmatic airways is dominated by eosinophils, mast cells, CD4+ T helper type 2 lymphocytes, and innate lymphoid cells that release cytokines including interleukin-4, interleukin-5, and interleukin-13, driving the characteristic features of the disease. Mast cell degranulation in response to allergen crosslinking of surface IgE antibodies releases histamine, leukotrienes, and prostaglandins that cause acute bronchoconstriction, while eosinophils release cytotoxic proteins that damage epithelial cells and perpetuate inflammation. Chronic inflammation leads to structural changes termed airway remodeling, including subepithelial fibrosis, smooth muscle hypertrophy, goblet cell hyperplasia, and neovascularization, which may become irreversible if inflammation is not adequately controlled. Asthma triggers encompass a diverse array of environmental exposures and endogenous factors that can precipitate bronchospasm and symptom flares in susceptible individuals. Aeroallergens represent the most common triggers in allergic asthma, including house dust mites, which thrive in bedding and carpeting, pet dander from cats and dogs, cockroach allergens, mold spores, and seasonal pollens from trees, grasses, and weeds. Respiratory tract infections, particularly viral upper respiratory infections caused by rhinovirus, represent the most common trigger for asthma exacerbations across all ages and phenotypes. Additional triggers include irritant exposures such as tobacco smoke, air pollution, strong odors, and occupational agents, as well as exercise particularly in cold dry air, certain medications including aspirin, NSAIDs, and beta-blockers, gastroesophageal reflux, emotional stress, and hormonal factors related to the menstrual cycle or pregnancy. Identification of individual patient triggers enables targeted avoidance strategies that can significantly reduce symptom burden and exacerbation frequency. The diagnosis of asthma requires documentation of characteristic respiratory symptoms combined with objective evidence of variable expiratory airflow limitation. Typical symptoms include recurrent episodes of wheeze, chest tightness, dyspnea, and cough that vary over time and in intensity, are often worse at night or early morning, and may be triggered by specific exposures or activities. Spirometry demonstrating airflow obstruction, defined as FEV1/FVC ratio below the lower limit of normal or below 0.70, with significant bronchodilator reversibility, specifically improvement in FEV1 of at least 12% and at least 200 mL following inhaled short-acting beta-agonist, confirms the diagnosis in the appropriate clinical context. When spirometry is normal but asthma remains clinically suspected, bronchoprovocation testing with methacholine or exercise challenge can demonstrate airway hyperresponsiveness, with a positive test supporting but not confirming the diagnosis. Serial peak expiratory flow monitoring showing excessive variability, specifically greater than 10% average daily diurnal variability or significant improvement with treatment, provides additional supportive evidence. Asthma phenotyping has emerged as an important approach to understanding disease heterogeneity and guiding targeted therapy selection, particularly for patients with severe or difficult-to-control disease. Allergic asthma, the most common phenotype, typically begins in childhood, is associated with atopic conditions including allergic rhinitis and eczema, demonstrates allergen-specific IgE sensitization, has elevated blood and sputum eosinophils, and generally responds well to inhaled corticosteroids and anti-IgE therapy. Non-allergic asthma often begins in adulthood, lacks IgE sensitization, and may be eosinophilic or neutrophilic, with neutrophilic asthma showing poorer response to corticosteroids. Aspirin-exacerbated respiratory disease represents a distinct phenotype characterized by asthma, chronic rhinosinusitis with nasal polyposis, and respiratory reactions to aspirin and other NSAIDs, often requiring aspirin desensitization and leukotriene modifier therapy. Exercise-induced bronchoconstriction, obesity-related asthma, and occupational asthma represent additional phenotypes with specific management considerations. Panel A: Cellular and molecular pathogenesis of asthma showing allergen presentation, Th2 cell activation, cytokine release, and downstream effects on eosinophils, mast cells, goblet cells, and smooth muscle. Panel B: Common asthma triggers organized by category (allergens, infections, irritants, medications, and other) with icons representing each trigger type. Panel C: Diagnostic algorithm for suspected asthma showing stepwise approach from symptom assessment through spirometry, bronchodilator reversibility testing, and methacholine challenge. Panel D: Asthma phenotype comparison chart showing characteristics of allergic, non-allergic eosinophilic, neutrophilic, aspirin-exacerbated, and obesity-related phenotypes. --- ### VII. Asthma Severity and Control Asthma severity classification is assessed retrospectively based on the treatment intensity required to achieve good symptom control and should be evaluated once the patient has been on controller therapy for several months. Intermittent asthma is defined by symptoms occurring two or fewer days per week, nighttime awakenings two or fewer times per month, short-acting beta-agonist use for symptom control two or fewer days per week, no interference with normal activity, and FEV1 greater than 80% predicted with normal FEV1/FVC. Mild persistent asthma involves symptoms more than twice weekly but not daily, nighttime awakenings three to four times per month, SABA use more than twice weekly, minor activity limitation, and FEV1 greater than 80% predicted. Moderate persistent asthma is characterized by daily symptoms, nighttime awakenings more than once weekly but not nightly, daily SABA need, some activity limitation, and FEV1 60-80% predicted. Severe persistent asthma involves symptoms throughout the day, frequent nighttime awakenings often nightly, SABA use several times daily, extreme activity limitation, and FEV1 less than 60% predicted. Asthma control assessment differs from severity classification in that it evaluates current symptom burden and future risk over the preceding two to four weeks, guiding decisions about stepping therapy up or down. Well-controlled asthma is defined by daytime symptoms occurring two or fewer days per week, no nighttime awakenings, SABA use two or fewer days per week for symptom relief, no interference with normal activities, normal or near-normal FEV1, and absence of exacerbations. Not well-controlled asthma indicates daytime symptoms more than twice weekly, nighttime awakenings one to three times per week, SABA use more than twice weekly, some activity limitation, FEV1 60-80% predicted, and one or two exacerbations requiring oral corticosteroids in the past year. Very poorly controlled asthma involves symptoms throughout the day, nighttime awakenings four or more times per week, SABA use several times daily, extreme activity limitation, FEV1 less than 60% predicted, and three or more exacerbations requiring oral corticosteroids annually. Regular assessment of control guides the treat-to-target approach that is fundamental to asthma management. Validated questionnaires provide standardized, reproducible assessment of asthma control that complements clinical evaluation and spirometry. The Asthma Control Test is a five-item patient-completed questionnaire evaluating activity limitation, shortness of breath, nighttime symptoms, rescue inhaler use, and overall asthma control over the past four weeks, with total scores ranging from 5 to 25 and a score of 20 or greater indicating well-controlled asthma. The Asthma Control Questionnaire is a seven-item instrument that can be completed by patients alone or with clinical assessment of FEV1, with scores ranging from 0 to 6 and a score of 0.75 or less indicating well-controlled disease while 1.5 or greater indicates inadequate control. These instruments should be administered at each clinical encounter to track control over time, with changes of 3 or more points on the ACT or 0.5 or more on the ACQ considered clinically meaningful. Documentation of control status using these standardized tools facilitates communication among providers and supports guideline-concordant therapy adjustments. The primary goals of asthma therapy are to achieve and maintain current symptom control while reducing future risk of adverse outcomes including exacerbations, accelerated lung function decline, and treatment-related side effects. Current control encompasses eliminating or minimizing daytime and nighttime symptoms, maintaining normal activity levels including exercise, minimizing rescue bronchodilator use, and achieving normal or near-normal lung function. Future risk reduction involves preventing exacerbations that require oral corticosteroids, emergency department visits, or hospitalizations, avoiding permanent airflow limitation that can result from chronic uncontrolled inflammation, and minimizing medication side effects particularly from systemic corticosteroids. The treat-to-target approach involves regularly assessing control and adjusting therapy stepwise, stepping up if control is not achieved after confirming adherence and inhaler technique, and stepping down if control has been maintained for at least three months to identify the minimum effective treatment. Patient education regarding self-management, trigger avoidance, proper inhaler technique, and recognition of worsening symptoms is essential to achieving these therapeutic goals. Panel A: Asthma severity classification grid showing criteria for intermittent, mild persistent, moderate persistent, and severe persistent asthma across domains of symptoms, nighttime awakenings, SABA use, activity limitation, and lung function. Panel B: Control assessment comparison table showing characteristics of well-controlled, not well-controlled, and very poorly controlled asthma. Panel C: Sample Asthma Control Test questionnaire with scoring interpretation showing cutoffs for well-controlled versus uncontrolled. Panel D: Treat-to-target concept diagram showing iterative cycle of assess control, adjust therapy, review response with step-up and step-down decision points. --- ### VIII. Stepwise Asthma Therapy The Global Initiative for Asthma 2023 guidelines present two treatment tracks reflecting evolving evidence about optimal reliever therapy, with Track 1 using ICS-formoterol as both maintenance and reliever therapy and Track 2 following the traditional approach with SABA as reliever plus ICS as controller. Track 1 is preferred for most adolescents and adults because using ICS-containing reliever therapy ensures that patients receive anti-inflammatory treatment with every dose of reliever, reducing the risk of severe exacerbations compared to SABA-only reliever use even in patients who are poorly adherent to maintenance therapy. The ICS-formoterol combination works as reliever because formoterol has rapid onset of action similar to SABA while providing the benefits of ICS with each dose, and studies have shown that this approach reduces severe exacerbations by approximately 60% compared to SABA reliever alone in mild asthma. Track 2, using SABA as reliever, remains an option when ICS-formoterol is unavailable, unaffordable, or not preferred by the patient, though it requires emphasizing adherence to daily ICS controller therapy. The stepwise treatment approach matches therapy intensity to disease severity and control status, with step-up indicated when control is inadequate and step-down considered when control has been maintained for at least three months. Step 1, for patients with infrequent symptoms occurring less than twice monthly, involves as-needed low-dose ICS-formoterol on Track 1 or as-needed SABA plus ICS taken together on Track 2, ensuring anti-inflammatory treatment accompanies every reliever dose. Step 2, for patients with symptoms twice monthly or more but not daily, adds low-dose daily ICS on Track 1 while maintaining ICS-formoterol as reliever, or uses daily low-dose ICS with SABA reliever on Track 2. Step 3, for patients with symptoms most days or waking with asthma weekly, involves low-dose ICS-LABA as maintenance with ICS-formoterol as reliever on Track 1, or medium-dose ICS or low-dose ICS-LABA with SABA reliever on Track 2. Step 4 escalates to medium-dose ICS-LABA maintenance, and Step 5 involves high-dose ICS-LABA plus referral for phenotypic assessment and consideration of add-on therapies. Add-on therapies at Step 5 are reserved for patients with severe asthma who remain uncontrolled despite high-dose ICS-LABA and optimized modifiable factors including adherence, inhaler technique, and comorbidities. Long-acting muscarinic antagonist therapy with tiotropium can be added to ICS-LABA, providing additional bronchodilation and modest reduction in exacerbation risk. Biologic therapies targeting specific inflammatory pathways offer transformative treatment options for eligible patients with severe disease. Low-dose oral corticosteroids may be necessary for some patients but should be used at the lowest effective dose and for the shortest duration possible given significant long-term toxicity including osteoporosis, adrenal suppression, diabetes, hypertension, cataracts, and increased infection risk. Bronchial thermoplasty, a bronchoscopic procedure that ablates airway smooth muscle with radiofrequency energy, may provide modest symptom improvement in select patients with severe disease refractory to medical therapy. Biologic therapies have revolutionized management of severe asthma by targeting specific inflammatory mediators and are selected based on patient phenotype and biomarkers. Omalizumab, an anti-IgE monoclonal antibody, is indicated for patients with moderate-to-severe allergic asthma with evidence of perennial allergen sensitization and elevated total IgE, typically administered as subcutaneous injection every two to four weeks. Anti-interleukin-5 agents including mepolizumab and benralizumab, and the anti-IL-5 receptor agent benralizumab, are indicated for severe eosinophilic asthma, typically defined by blood eosinophil count of 150-300 cells per microliter or higher depending on the specific agent. Dupilumab, targeting the IL-4 receptor alpha subunit that signals for both IL-4 and IL-13, is approved for moderate-to-severe eosinophilic asthma or oral corticosteroid-dependent asthma with broad efficacy across type 2 high phenotypes. Tezepelumab, targeting thymic stromal lymphopoietin (TSLP), an upstream epithelial cytokine, has demonstrated efficacy across asthma phenotypes including patients without elevated eosinophils, representing an option for severe asthma that is not clearly type 2 high. Panel A: GINA stepwise therapy diagram showing Steps 1-5 with Track 1 (ICS-formoterol reliever) and Track 2 (SABA reliever) side by side, including controller and reliever options at each step. Panel B: Decision algorithm for selecting preferred reliever therapy (ICS-formoterol versus SABA) based on patient characteristics and guideline recommendations. Panel C: Add-on therapy options at Step 5 including LAMA, biologics, low-dose OCS, and bronchial thermoplasty with their indications and evidence level. Panel D: Biologic therapy selection guide showing agent names, molecular targets, biomarker criteria for selection (IgE, eosinophils, FeNO), and administration routes and frequencies. --- ### IX. Asthma Exacerbation Assessment of asthma exacerbation severity is critical for determining appropriate treatment intensity and disposition, with severity categorized as mild-moderate, severe, or life-threatening based on clinical parameters. Mild-moderate exacerbations are characterized by the ability to speak in sentences, possible agitation but full alertness, increased respiratory rate but not exceeding 30 breaths per minute, absence of accessory muscle use, audible wheeze, oxygen saturation of 90% or greater on room air, and peak expiratory flow greater than 50% predicted. Severe exacerbations manifest with ability to speak only in words, marked agitation, respiratory rate exceeding 30 breaths per minute, prominent accessory muscle use, loud wheeze throughout chest, oxygen saturation below 90%, and peak flow 25-50% predicted. Life-threatening exacerbations present with inability to speak, drowsiness, confusion, or exhaustion, may have paradoxical thoracoabdominal movement, characteristically have a silent chest due to minimal air movement, oxygen saturation below 90%, and peak flow below 25% predicted or unmeasurable, requiring immediate aggressive intervention and preparation for intubation. Initial management of acute asthma exacerbations follows a standardized approach regardless of care setting, with treatment intensity matched to severity assessment. Supplemental oxygen should be administered to maintain oxygen saturation between 93-95% in adults and 94-98% in children, avoiding both hypoxemia and excessive oxygen that may mask deterioration. Inhaled short-acting beta-agonists represent first-line bronchodilator therapy, typically albuterol administered via metered-dose inhaler with spacer, delivering 4-8 puffs every 20 minutes for the first hour in severe exacerbations, or via continuous nebulization in life-threatening presentations. Inhaled ipratropium bromide added to SABA provides additive bronchodilation in moderate-severe exacerbations and should be administered concurrently, typically 0.5 mg nebulized or 4-8 puffs via MDI with spacer repeated every 20 minutes as needed. Systemic corticosteroids are essential for treating airway inflammation and should be administered early, with oral prednisone or prednisolone 40-60 mg in adults or 1-2 mg/kg in children being equivalent to intravenous routes in patients who can take oral medications. Additional therapies are considered for patients with severe exacerbations not responding adequately to initial treatment. Intravenous magnesium sulfate 2 grams administered over 20 minutes provides smooth muscle relaxation and may reduce hospital admission rates when given to patients with severe exacerbations, specifically those with FEV1 or peak flow less than 25% predicted at presentation. Epinephrine by intramuscular injection may be appropriate for patients with associated anaphylaxis or angioedema but is not routinely recommended for asthma exacerbations alone. Heliox, a mixture of helium and oxygen, may reduce airway resistance and work of breathing in severe obstruction but requires high concentrations of helium limiting its use in hypoxemic patients and is not widely available. Intravenous aminophylline and inhaled anesthetics have limited evidence and significant toxicity, reserved only for patients with life-threatening exacerbations failing maximal conventional therapy. Non-invasive positive pressure ventilation may be attempted in selected patients with severe exacerbations to avoid intubation, though evidence is limited and close monitoring for deterioration is essential. Disposition decisions following asthma exacerbation management depend on response to treatment and presence of risk factors for adverse outcomes. Criteria supporting discharge home include sustained response to bronchodilator therapy with PEF greater than 70% predicted or personal best, oxygen saturation greater than 94% on room air, resolution of accessory muscle use and respiratory distress, ability to use inhalers correctly, availability of and access to follow-up care, adequate home environment, and patient understanding and acceptance of discharge plan. Factors favoring hospital admission include PEF remaining below 40% predicted after treatment, persistent hypoxemia despite supplemental oxygen, altered mental status or exhaustion, prior near-fatal asthma or intubation, concurrent serious medical or psychiatric conditions, and inadequate social support or follow-up access. Discharge planning must include completion of a corticosteroid course, typically 5-7 days of oral prednisone 40-50 mg daily, review and demonstration of inhaler technique, provision of or prescription for adequate controller therapy, written asthma action plan, identification and plans to address triggers, and scheduled follow-up within one to four weeks. Panel A: Asthma exacerbation severity assessment grid showing clinical parameters (speech, alertness, respiratory rate, accessory muscles, wheeze, oxygen saturation, peak flow) across mild-moderate, severe, and life-threatening categories. Panel B: Treatment algorithm for acute asthma exacerbation showing initial assessment, initial treatment, reassessment, and subsequent decision points for escalation or discharge. Panel C: Discharge criteria checklist with objective measures and patient factors to assess before releasing patient. Panel D: Written asthma action plan template showing green (doing well), yellow (caution), and red (emergency) zones with corresponding symptoms and medication instructions. --- ### X. Special Topics Proper inhaler technique is essential for effective drug delivery and asthma and COPD control, yet studies consistently show that 70-90% of patients use their inhalers incorrectly, significantly compromising treatment efficacy. Pressurized metered-dose inhalers require coordination between actuation and inhalation, which many patients find challenging; use of a valved holding chamber or spacer eliminates this coordination requirement, improves drug deposition in the lungs, and reduces oropharyngeal side effects including dysphonia and oral candidiasis from inhaled corticosteroids. Dry powder inhalers do not require coordination but depend on adequate inspiratory flow rate to deaggregate the powder and generate respirable particles, making them unsuitable for young children, patients with severe exacerbations, or those with cognitive impairment. Soft mist inhalers produce a slow-moving aerosol that is easier to inhale correctly than MDIs but still require appropriate timing and technique. Healthcare providers should assess inhaler technique at every visit, correct errors using demonstration and teach-back methods, and consider device switching if technique cannot be mastered despite repeated education. Alpha-1 antitrypsin deficiency is a genetic condition causing COPD and liver disease that should be considered in all patients with airflow obstruction, particularly those presenting at young ages with minimal smoking history. The condition follows autosomal codominant inheritance, with the most clinically significant phenotype being PiZZ homozygotes who have severely reduced AAT levels typically below 11 micromoles per liter and develop panacinar emphysema predominantly affecting the lung bases. Clinical clues suggesting AAT deficiency include COPD onset before age 45, emphysema in a never-smoker or minimal smoker, lower lobe predominant emphysema pattern on imaging, associated liver disease, family history of emphysema or liver disease, and bronchiectasis without clear cause. Screening involves measuring serum AAT level, with phenotyping or genotyping performed if the level is low. Augmentation therapy with intravenous pooled human AAT is available for patients with severe deficiency and established emphysema, though evidence for clinical efficacy in slowing lung function decline remains limited. Smoking cessation is the most important intervention for COPD prevention and management, and healthcare providers should offer cessation support at every clinical encounter with patients who smoke. Behavioral counseling combined with pharmacotherapy is more effective than either approach alone, with even brief counseling interventions significantly increasing quit rates. Nicotine replacement therapy in various forms including transdermal patches, gum, lozenges, nasal spray, and oral inhaler approximately doubles cessation rates by reducing withdrawal symptoms and cravings. Bupropion, originally developed as an antidepressant, reduces cravings and withdrawal symptoms and can be combined with NRT for additional benefit. Varenicline is the most effective single pharmacotherapy, acting as a partial agonist at nicotinic acetylcholine receptors to reduce cravings and withdrawal while blocking the rewarding effects of smoking, and may be combined with NRT for maximally effective treatment in highly dependent smokers. Asthma and COPD management during pregnancy requires careful attention to both fetal safety and the risks of poorly controlled disease, with the guiding principle being that the risks of uncontrolled disease generally outweigh the risks of controller medications. Poorly controlled asthma during pregnancy is associated with preeclampsia, preterm birth, low birth weight, and maternal morbidity, making disease control a priority. Inhaled corticosteroids have extensive safety data in pregnancy and should be continued; budesonide has the most human pregnancy data and is often preferred, though there is no evidence that other ICS agents are harmful. LABAs, particularly salmeterol and formoterol, may be continued if needed for control, though data are more limited than for ICS. Short-acting beta-agonists are safe for acute symptom relief. Oral corticosteroids, while having some association with cleft palate when used in the first trimester and with preterm birth with prolonged use, should be administered when needed for exacerbation management because the risks of uncontrolled severe asthma outweigh medication risks. Leukotriene receptor antagonists have limited human pregnancy data but may be continued if essential for control, while omalizumab continuation may be considered in patients whose disease was well-controlled on this agent before pregnancy. Panel A: Inhaler device comparison showing proper technique steps, advantages, and limitations for pMDI with spacer, dry powder inhaler, soft mist inhaler, and nebulizer. Panel B: Alpha-1 antitrypsin deficiency clinical features, diagnostic algorithm from serum level through genotyping, and treatment options. Panel C: Smoking cessation pharmacotherapy comparison showing mechanism, efficacy, dosing, and precautions for NRT, bupropion, and varenicline. Panel D: Pregnancy considerations table showing asthma medications with their safety classification and recommendations for continuation or modification during pregnancy. --- ## Summary - COPD is characterized by fixed airflow obstruction primarily from smoking, while asthma features reversible obstruction often with allergic inflammation - COPD diagnosis requires post-bronchodilator FEV1/FVC less than 0.70, with GOLD staging based on FEV1 percent predicted - COPD management foundations include smoking cessation, vaccinations, and pulmonary rehabilitation for all patients - GOLD groups (A, B, E) guide initial COPD pharmacotherapy, with LAMAs preferred for exacerbation prevention and ICS added for eosinophilic disease - COPD exacerbations require bronchodilators, systemic corticosteroids, antibiotics for purulent sputum, and NIV for hypercapnic respiratory failure - Asthma diagnosis requires variable symptoms plus objective evidence of reversible airflow limitation on spirometry - Asthma control assessment evaluates symptoms, nighttime awakenings, SABA use, and activity limitation to guide therapy adjustments - GINA stepwise therapy now prefers ICS-formoterol as reliever on Track 1, ensuring anti-inflammatory treatment with every rescue dose - Biologic therapies target IgE, IL-5, IL-4/13, or TSLP for severe eosinophilic or allergic asthma uncontrolled on high-dose ICS-LABA - Asthma exacerbations require oxygen, frequent SABA, ipratropium for severe cases, systemic corticosteroids, and magnesium for severe presentations - Inhaler technique education is critical for both diseases and should be assessed and corrected at every clinical encounter --- ## Key Terms | Term | Definition | |------|------------| | COPD | Chronic obstructive pulmonary disease with fixed airflow limitation | | FEV1/FVC | Ratio of forced expiratory volume in one second to forced vital capacity | | LAMA | Long-acting muscarinic antagonist bronchodilator | | LABA | Long-acting beta-agonist bronchodilator | | ICS | Inhaled corticosteroid anti-inflammatory therapy | | Bronchoreversibility | Improvement in FEV1 of at least 12% and 200 mL after bronchodilator | | ACT | Asthma Control Test standardized questionnaire | | NIV | Non-invasive ventilation using bilevel positive airway pressure | | GOLD | Global Initiative for Chronic Obstructive Lung Disease guidelines | | GINA | Global Initiative for Asthma guidelines | --- *This content is subject to the [MIT License](https://opensource.org/licenses/MIT). © 2024–2026 Hibbert School of Medicine.*