IM28.1-26 | Obstructive Airway Diseases — Glossary

A structured clinical tool for smoking cessation counselling: Ask (about tobacco use at every visit), Advise (clear personal non-judgmental advice to quit), Assess (readiness and dependence level), Assist (set quit date, prescribe pharmacotherapy, provide counselling), Arrange (follow-up within 1–2 weeks of quit date); evidence-based; doubles cessation attempt rates even when partially applied.

A standardised exercise capacity test measuring the maximum distance a patient can walk on a flat surface in 6 minutes; used in COPD assessment to quantify functional limitation, guide pulmonary rehabilitation, and assess eligibility for long-term oxygen therapy.

Repeated administration of increasing doses of a sensitising allergen (subcutaneous or sublingual) to induce immunological tolerance; indicated for IgE-mediated allergic asthma with a single dominant allergen not controlled pharmacologically; risk of anaphylaxis with subcutaneous route; 3–5 year course required.

A serine protease inhibitor synthesised in the liver; primary function in the lung is to inhibit neutrophil elastase; deficiency (classically PiZZ genotype) allows uninhibited elastase activity leading to panacinar emphysema, predominantly at the lung bases.

Three cardinal symptoms of COPD exacerbation: (1) increased dyspnoea, (2) increased sputum volume, (3) purulent sputum; a Type-1 exacerbation has all three (highest bacterial aetiology likelihood); Type-2 has two; Type-3 has one; guides antibiotic decision-making.

Analysis of a blood sample taken directly from an artery (typically radial) measuring pH, PaO₂, PaCO₂, HCO₃⁻, and base excess; provides the definitive assessment of oxygenation, ventilation, and acid-base status; essential in acute severe OAD and for LTOT assessment.

Also called Samter's triad; a clinical syndrome of asthma, nasal polyps, and sensitivity to aspirin and NSAIDs; mechanism is COX-1 inhibition diverting arachidonic acid metabolism toward excess leukotriene production, causing severe bronchospasm within minutes of NSAID ingestion.

A heterogeneous disease characterised by chronic airway inflammation, variable respiratory symptoms (wheeze, dyspnoea, chest tightness, cough), and variable expiratory airflow limitation that is reversible spontaneously or with bronchodilator therapy.

A personalised written plan given to asthma patients specifying what to do in the green zone (stable), yellow zone (worsening — increase reliever, start prednisolone), and red zone (emergency — go to A&E); reduces emergency visits and exacerbation-related mortality; should be updated at every clinic visit.

A genetic predisposition to develop IgE-mediated sensitisation to common environmental allergens; the strongest risk factor for allergic asthma; characterised by elevated total and specific IgE, eosinophilia, and often a personal or family history of asthma, allergic rhinitis, or eczema.

Increased anterior-posterior diameter of the thorax (approaching the transverse diameter) with horizontal ribs and kyphosis; a sign of chronic lung hyperinflation in severe emphysema; reflects air trapping and permanent chest wall remodelling.

Chronic obstructive pulmonary disease caused by long-term exposure to smoke from combustion of wood, crop residues, or dung in poorly ventilated indoor environments; affects primarily rural women in India who cook over traditional chulhas; responsible for a substantial proportion of never-smoker COPD in low-income countries.

Combustion products from wood, crop residue, cow dung, and coal used for cooking and heating; a major cause of COPD in non-smoking Indian women from sustained indoor exposure in poorly-ventilated households; associated with a predominantly wall-thickening COPD phenotype.

An abnormal breath sound characterised by a harsh, tubular quality with an audible expiratory phase equal in duration to inspiration; heard over consolidated lung (the solid lung transmits sound like a bronchus); distinguishes consolidation from collapse or effusion.

An increase in FEV1 of ≥12% AND ≥200 mL from baseline after inhalation of a short-acting bronchodilator (e.g., salbutamol 400 mcg); the physiological criterion that distinguishes asthma (reversible obstruction) from COPD (persistent obstruction).

Spirometry performed before and 15–30 minutes after inhalation of a short-acting bronchodilator (salbutamol 400 mcg or ipratropium 160 mcg); significant reversibility = FEV1 increase ≥12% AND ≥200 mL — supports asthma over COPD.

Occupational lung disease from cotton dust inhalation in textile workers; characterised by Monday morning chest tightness and dyspnoea that improves during the week as tolerance develops; reflects a mixture of acute bronchospasm and chronic airway inflammation from endotoxin in cotton dust.

Wheeze caused by left ventricular failure; peribronchial oedema from elevated pulmonary venous pressure compresses small airways, causing wheeze that mimics bronchospasm; distinguished from true asthma by elevated JVP, fine basal crackles, and response to diuretics rather than bronchodilators.

An 8-item validated patient-reported QoL questionnaire for COPD (score 0–40); scores: 0–10 = low impact, 11–20 = medium impact, 21–30 = high impact, 31–40 = very high impact; used in GOLD ABE assessment to determine symptom burden; quick and easy to administer in clinic.

Defined clinically as productive cough for ≥3 months per year for ≥2 consecutive years in the absence of another causative condition; represents the airway component of COPD, characterised by goblet cell hyperplasia, mucus hypersecretion, and airway wall inflammation.

A heterogeneous lung condition characterised by chronic respiratory symptoms and persistent, progressive, not-fully-reversible airflow limitation (post-bronchodilator FEV1/FVC < 0.70), caused by airway (bronchitis, bronchiolitis) and/or alveolar (emphysema) abnormalities, primarily from noxious exposures including tobacco smoke.

Right ventricular hypertrophy and eventual failure caused by pulmonary hypertension secondary to lung disease; in COPD, caused by hypoxic pulmonary vasoconstriction; clinically manifests as raised JVP, right ventricular heave, peripheral oedema, and hepatomegaly.

The day-to-day variation in PEFR measured as (evening PEFR − morning PEFR) / evening PEFR × 100%; variability >20% on most days over 2–4 weeks confirms variable airflow limitation consistent with asthma; used when resting spirometry is normal.

A measure of the capacity of the lungs to transfer gas from alveolar air into the capillary blood; reduced in emphysema (loss of alveolar surface area and capillary bed); normal or elevated in asthma and chronic bronchitis; used to distinguish emphysema from other obstructive patterns.

An inhaler device that releases drug as a powder on actuation; requires adequate inspiratory flow (≥30 L/min) to deaggregate and carry particles to the airways; technique error is slow inhalation; not suitable for acute severe exacerbations when inspiratory flow is compromised; different devices (Turbuhaler, Diskus, Handihaler) have different loading procedures.

Immediate bronchospasm occurring within minutes of allergen exposure in sensitised individuals; mediated by IgE-dependent mast cell degranulation releasing histamine, prostaglandins, and leukotrienes; corresponds to the immediate fall in FEV1 on allergen challenge testing.

Anatomical destruction of air spaces distal to the terminal bronchiole with permanent enlargement of alveolar spaces and loss of alveolar walls, without significant fibrosis; results from protease-antiprotease imbalance; causes hyperinflation and loss of elastic recoil.

A validated questionnaire measuring physical nicotine dependence; key items: time to first cigarette (within 5 minutes = very high dependence), cigarettes per day; total score 0–10; score ≥6 = high dependence requiring pharmacotherapy; first cigarette within 5 minutes is the single strongest predictor of dependence severity.

The measured FEV1 expressed as a percentage of the age-, height-, sex-, and ethnicity-matched reference ('predicted') value; used for GOLD grading of COPD severity: GOLD 1 ≥80%, GOLD 2 50–79%, GOLD 3 30–49%, GOLD 4 <30%.

The ratio of forced expiratory volume in 1 second to forced vital capacity; the key spirometric parameter for diagnosing airflow obstruction; post-bronchodilator FEV1/FVC < 0.70 is the GOLD criterion for COPD.

European-standard particulate respirators providing ≥94% (FFP2) or ≥99.9% (FFP3) filtration efficiency for particles ≥0.3 mcm; equivalent to N95 and N100 US standards; appropriate for silica dust, cotton dust, and fine particulate occupational exposures; requires proper fit-testing and donning instruction; surgical masks are NOT equivalent and do not protect against silica.

A graphic representation of expiratory (and inspiratory) flow plotted against lung volume during forced spirometry; the normal expiratory limb shows a sharp peak then linear decline; obstruction produces a scooped-out concave expiratory limb; restriction produces a narrow but preserved-shape loop.

Global Initiative for Asthma; produces the internationally adopted evidence-based guidelines for asthma management and prevention; classifies asthma by severity (intermittent, mild/moderate/severe persistent) and control (well-controlled, partly controlled, uncontrolled).

The Global Initiative for Asthma evidence-based treatment ladder with 5 steps; preferred reliever from Step 1 is low-dose ICS-formoterol (MART approach); escalation is driven by symptom control assessment; Step 3 = ICS/LABA; Steps 4–5 involve high-dose combinations and biologic therapies.

The GOLD 2023 patient classification for COPD management: Group A (low symptoms, low exacerbation risk) — bronchodilator; Group B (high symptoms, low risk) — LAMA+LABA; Group E (exacerbation risk regardless of symptoms) — LAMA+LABA ± ICS; drives initial pharmacological treatment choice.

The Global Initiative for Chronic Obstructive Lung Disease staging system for COPD severity: GOLD 1 (FEV1 ≥80%), GOLD 2 (50–79%), GOLD 3 (30–49%), GOLD 4 (<30%) of predicted, based on post-bronchodilator FEV1.

A five-tier evidence-based framework for workplace health and safety, from most to least effective: (1) elimination, (2) substitution, (3) engineering controls (LEV, wet drilling), (4) administrative controls (job rotation), (5) PPE; PPE is the last resort because it relies on individual compliance and does not reduce the hazard itself.

A percussion note that is more resonant than normal, with a lower pitch and longer duration; found over air-trapping (emphysema, bilateral) or pneumothorax (unilateral); indicates an increase in the air-to-tissue ratio beneath the percussion point.

Radiographic signs of pulmonary hyperinflation in COPD: depressed flat diaphragms (below the anterior end of the 6th rib), increased retrosternal airspace >3 cm on lateral CXR, horizontal orientation of the ribs, and barrel-shaped thorax; reflects chronic air trapping and emphysema.

The ventilatory drive maintained by peripheral chemoreceptors (carotid and aortic bodies) in response to low PaO₂; becomes the dominant stimulus in chronic CO₂ retainers where central CO₂ sensitivity is blunted by bicarbonate compensation; suppression by excess oxygen can cause dangerous hypercapnia.

An anti-inflammatory drug delivered directly to the airways by inhalation; budesonide, fluticasone, beclomethasone; reduces eosinophilic airway inflammation in asthma; cornerstone of asthma management; limited role in COPD except in frequent exacerbators with high eosinophil count.

A fixed or portable ducted system placed close to the dust- or fume-generating source to capture airborne hazardous material before it disperses into the breathing zone; standard engineering control in regulated manufacturing; reduces workplace airborne concentrations more effectively than general dilution ventilation or PPE.

Bronchodilator with 12–24 hour duration; salmeterol, formoterol, indacaterol, vilanterol; used as maintenance therapy; LABA monotherapy is contraindicated in asthma (must always be combined with ICS); used alone or with LAMA in COPD.

An anticholinergic bronchodilator with 24-hour duration; tiotropium, glycopyrronium, aclidinium; reduces bronchomotor tone by blocking M3 receptors on airway smooth muscle; the foundation of COPD maintenance therapy; reduces exacerbation frequency.

Supplemental oxygen prescribed for ≥15 hours per day for COPD patients meeting criteria: resting PaO₂ ≤55 mmHg (or ≤60 mmHg with cor pulmonale or polycythaemia); the only pharmacological intervention proven to improve survival in severe COPD with chronic hypoxaemia.

Maintenance And Reliever Therapy — using a single ICS/formoterol inhaler as both the daily controller AND the as-needed reliever for asthma; preferred by GINA 2023 because each reliever use also delivers anti-inflammatory ICS; reduces severe exacerbation risk compared to SABA-only reliever strategies.

A bronchial provocation test used to confirm airway hyperresponsiveness in suspected asthma when spirometry is normal at rest; methacholine is inhaled in increasing doses; a positive test is a fall in FEV1 ≥20% at a concentration of ≤8 mg/mL (PC20); confirms asthma diagnosis.

A cysteinyl leukotriene receptor-1 antagonist taken orally; add-on therapy in asthma not controlled on low-dose ICS; particularly useful in exercise-induced asthma, aspirin-exacerbated respiratory disease (AERD), and asthma with allergic rhinitis; FDA black box warning for neuropsychiatric effects.

A patient-centred, non-confrontational communication style for promoting behaviour change; explores ambivalence using reflective listening, open questions, and developing discrepancy between stated values and current behaviour; more effective than directive advice for pre-contemplative or contemplative patients; core technique for smoking cessation counselling.

The Medical Research Council graded 5-point scale for breathlessness severity: Grade 1 (only with strenuous exertion) to Grade 5 (too breathless to leave the house or perform self-care); used to quantify functional impairment in COPD and guide treatment escalation.

Pharmacotherapy for smoking cessation delivering controlled doses of nicotine without the other toxins of tobacco smoke; reduces withdrawal symptoms and craving; forms include transdermal patch (16 or 24 hour), gum, lozenge, nasal spray, inhaler; combination patch + short-acting NRT is recommended for high dependence; safe in cardiovascular disease and asthma.

Positive pressure ventilation delivered via a tight-fitting face mask without tracheal intubation; first-line treatment for acute hypercapnic respiratory failure in AECOPD when pH <7.35 and PaCO₂ elevated; reduces intubation rate and mortality; contraindicated in reduced consciousness, haemodynamic instability, vomiting.

A spectrum of conditions characterised by airflow limitation due to airway narrowing, inflammation, or dynamic collapse; includes asthma and COPD as the major entities; defined physiologically by a reduced FEV1/FVC ratio.

Asthma caused by workplace sensitisers or irritants; classic examples include flour dust in bakers, isocyanates in spray painters, and latex in healthcare workers; characterised by work-related symptom pattern; confirmed by serial PEFR monitoring and specific bronchial challenge.

A measure of cumulative tobacco smoking exposure: number of packs of cigarettes smoked per day multiplied by the number of years smoked (1 pack = 20 cigarettes); 20 pack-years = 1 pack/day for 20 years; the most standardised way to quantify smoking-related COPD risk.

Type of emphysema affecting the entire acinus (respiratory bronchioles, alveolar ducts, and alveolar sacs) uniformly; predominantly involves the lower lobes; characteristic of alpha-1 antitrypsin deficiency; contrasts with centri-acinar emphysema (upper-lobe predominant) caused by tobacco smoking.

The maximum airflow rate achieved during a maximal forced expiratory effort from total lung capacity, measured in L/min using a peak flow meter; primarily reflects large-airway calibre; used for asthma monitoring, acute severity classification, and diurnal variability assessment.

The highest PEFR achieved by an individual patient during a period of optimal asthma control (ideally measured over 2–3 weeks on optimal therapy); the reference value for acute asthma severity classification (percentage of personal best).

Homozygous expression of the Z allele of the SERPINA1 gene; causes AAT serum levels <15% of normal; classical genotype of AAT deficiency associated with early-onset (age 40–50 years) panacinar emphysema and hepatic disease due to Z-protein accumulation in hepatocytes.

A Government of India scheme providing free LPG connections to households below the poverty line (BPL) to replace biomass fuel cooking, reducing indoor air pollution and associated COPD and cardiovascular risk; physicians should refer eligible patients for PMUY enrollment as part of prevention counselling.

An expiratory phase that exceeds twice the duration of inspiration (I:E ratio > 1:2); a clinical sign of airflow obstruction detected on auscultation; reflects the increased resistance to airflow during forced expiration through narrowed small airways.

The prevailing mechanism explaining emphysema: an imbalance between proteolytic enzymes (primarily neutrophil elastase and matrix metalloproteinases) and their inhibitors (primarily AAT) leads to progressive degradation of alveolar elastin and connective tissue, causing permanent airspace enlargement.

Non-invasive measurement of arterial oxygen saturation (SpO₂) using light absorption by oxyhaemoglobin and deoxyhaemoglobin; rapid, continuous, and widely available; does not measure ventilation (PaCO₂) or pH; falsely normal in CO poisoning.

An exaggerated fall in systolic blood pressure (>10 mmHg) during normal inspiration; occurs in severe asthma due to large swings in intrathoracic pressure; measured by auscultation of Korotkoff sounds during slow inflation and deflation of a sphygmomanometer cuff.

A breathing technique spontaneously adopted by COPD patients — exhaling slowly through partially closed lips — which generates intrinsic PEEP, maintains small airway patency during expiration, reduces dynamic hyperinflation, and improves gas exchange efficiency.

Erythrocytosis (elevated haemoglobin and red cell mass) occurring as a compensatory response to chronic hypoxaemia; the kidney secretes increased erythropoietin in response to low PaO₂, stimulating red cell production; seen in advanced COPD with persistent hypoxaemia.

A bronchodilator drug class acting on airway β₂-receptors to cause rapid smooth muscle relaxation; onset 5 minutes, duration 4–6 hours; salbutamol (albuterol) is the prototype; the first-line reliever for acute bronchospasm in both asthma and COPD exacerbations.

Absence of wheeze in a breathless, distressed patient due to severely reduced airflow — insufficient to generate the oscillating sound of wheeze; occurs in near-fatal asthma or extreme COPD exacerbation; signifies impending respiratory arrest, not clinical improvement.

An irreversible fibrosing lung disease caused by chronic inhalation of crystalline free silica (quartz dust); occurs in quarry workers, sandblasters, tunnel workers; no treatment reverses established disease; prevention = engineering controls (wet drilling, LEV) + surveillance spirometry; co-morbidity with TB (silica impairs alveolar macrophage function).

A large-volume holding chamber attached to a pressurised metered-dose inhaler (pMDI) to act as a reservoir; eliminates the need for press-and-breathe coordination; reduces oropharyngeal deposition and ICS side effects; recommended for all pMDI users, especially children and the elderly.

A pulmonary function test measuring the volume and flow of air during forced expiratory and inspiratory manoeuvres; provides FEV1, FVC, FEV1/FVC ratio, and flow-volume loops; the gold standard for diagnosis and severity assessment of obstructive and restrictive lung disease.

A markedly dull, non-resonant percussion note heard over a pleural effusion; more dull than the dullness of consolidation; characterised by a flat, wood-like quality; the upper border is horizontal and shifts with posture (shifting dullness).

A pneumothorax where air enters the pleural space through a one-way valve mechanism, progressively accumulating under pressure; causes tracheal deviation away from the affected side, absent breath sounds, hyper-resonance, and haemodynamic compromise; requires emergency needle decompression.

A methylxanthine phosphodiesterase inhibitor with bronchodilator and anti-inflammatory effects; narrow therapeutic window (10–20 mcg/mL); third-line add-on in COPD and severe refractory asthma; numerous drug interactions and toxicity risks (arrhythmias, seizures); serum level monitoring required.

Displacement of the trachea from the midline; deviation away from the affected side occurs in tension pneumothorax and large pleural effusion (pushed away); deviation toward the affected side occurs in lung collapse or fibrosis (pulled toward).

A behaviour change model describing five stages: precontemplation (not thinking about change), contemplation (considering change), preparation (planning to act within 30 days), action (actively changing), and maintenance (sustaining change); cessation counselling should match the patient's current stage.

Hypoxaemia (PaO₂ <60 mmHg) without hypercapnia (PaCO₂ normal or low); caused by V/Q mismatch, shunt, or diffusion impairment; occurs in mild-moderate COPD, pneumonia, pulmonary embolism, and acute asthma without ventilatory fatigue.

Respiratory failure characterised by both hypoxia (PaO₂ < 60 mmHg) and hypercapnia (PaCO₂ > 45 mmHg); caused by alveolar hypoventilation; occurs in severe COPD when respiratory muscle effort can no longer compensate for increased airway resistance.

Ventilation-perfusion mismatch; the predominant mechanism of hypoxia in obstructive airway disease; occurs when areas of lung with obstructed airways continue to receive blood flow but deliver reduced ventilation, resulting in poorly oxygenated blood entering the pulmonary veins.

A partial agonist at α4β2 nicotinic acetylcholine receptors; reduces craving and withdrawal (agonist effect) and reduces reward from smoking if relapsed (partial agonist ceiling); most effective single pharmacotherapy for smoking cessation; NNT approximately 5; dose-titrated over first week; start 1 week before quit date; monitor for neuropsychiatric effects.

An oxygen delivery device that uses the Venturi principle to entrain room air in a precise ratio, delivering a fixed FiO₂ (24%, 28%, 35%, 40%, or 60%) regardless of patient breathing pattern; device of choice for COPD exacerbation to deliver controlled oxygen at SpO₂ target 88–92%.

The transmission of voice sounds through the lung to the chest wall, assessed by asking the patient to say '99' while auscultating; increased over consolidated lung (consolidation transmits sound better); decreased (or absent) over effusion or pneumothorax.

A continuous, musical, high-pitched (or low-pitched) added breath sound produced by oscillation of the airway walls in partially obstructed airways; expiratory predominance in asthma and COPD; polyphonic (multiple pitches) in diffuse small-airway obstruction; monophonic (single pitch) in localised obstruction.