Emphysema

Definition

Emphysema is the permanent enlargement and destruction of the alveoli — the tiny air sacs where gas exchange occurs — with loss of the elastic recoil that normally helps the lungs empty. It sits within the COPD spectrum and commonly coexists with chronic bronchitis. The defining problem is not getting air in; it is getting it out.

Pathophysiology

Alveolar destruction

Chronic exposure to noxious particles drives neutrophilic and macrophage inflammation and an imbalance between proteases and antiproteases. Elastin in the alveolar walls is degraded faster than it can be replaced, and the walls break down, merging many small air sacs into fewer large ones. Surface area for gas exchange falls, and so does gas transfer.

Loss of elastic recoil and airway tethering

Two consequences follow from destroyed alveolar walls. Elastic recoil — the passive force that empties the lung — is lost, so expiration becomes slow and effort-dependent. And the alveolar attachments that tether small airways open are destroyed, so those airways collapse during expiration. Air enters but cannot leave.

Dynamic hyperinflation — the key mechanism

On exertion, breathing rate rises and expiratory time shortens, so progressively more air is trapped with each breath. The lung inflates further, the diaphragm flattens and shortens, and the inspiratory muscles are forced to operate at a mechanical disadvantage on an unfavourable part of their length–tension curve. The patient must generate more effort for less volume — and that mismatch between effort and achieved ventilation is what the brain interprets as breathlessness.¹ This mechanism explains almost everything that helps: pursed-lip breathing, bronchodilators, leaning forward, paced exertion and lung volume reduction all work by reducing hyperinflation, not by improving gas exchange.

Gas exchange

Destruction of the alveolar–capillary bed reduces diffusing capacity (a low DLCO) and produces ventilation–perfusion mismatch, causing exertional and later resting hypoxaemia. Chronic hypoxaemia drives pulmonary vasoconstriction, pulmonary hypertension and eventually right heart strain.

Co-morbidities

As in COPD, common co-morbidities include cardiovascular disease, lung cancer, osteoporosis, sarcopenia and muscle wasting, anxiety and depression, gastro-oesophageal reflux and obstructive sleep apnoea. Pneumothorax is a particular risk where large bullae are present, and distinguishing a large bulla from a pneumothorax on plain film is a recognised trap with serious consequences if a bulla is drained.

Prevalence

Emphysema is one of the two main components of COPD, which affects roughly one in thirteen Australians over 40 and is a leading cause of death and hospitalisation. It is strongly related to smoking and is substantially under-diagnosed — symptoms are commonly attributed to ageing, weight or unfitness, and patients reduce their activity to stay within their limits, so the breathlessness that would prompt presentation never occurs.

Causes and risk factors

• Tobacco smoking — by far the commonest cause, with a clear dose–response relationship.
• Occupational dusts, vapours, gases and fumes, and biomass smoke.
• Air pollution, including indoor wood heating and bushfire smoke.
• Alpha-1 antitrypsin deficiency — an important inherited cause of early-onset, often lower-zone panlobular emphysema, particularly in younger patients, non-smokers, or those with a family history or coexisting liver disease. It should be tested for at least once in everyone with emphysema.
• Childhood respiratory illness and impaired lung growth, which reduce peak lung function and bring the threshold for symptoms forward by years.
• HIV, intravenous drug use and connective tissue disease in a small minority.

Symptoms

Typical features

• Progressive breathlessness — at first only on hills and stairs, later with daily activities and eventually at rest.
• A sense of not being able to breathe out fully, and of the next breath arriving before the last has finished.
• Reduced exercise tolerance and fatigue, often accommodated so gradually the person does not notice.
• Cough, usually less prominent than in chronic bronchitis, and periodic exacerbations.
• Weight and muscle loss in advanced disease; a barrel-shaped chest and pursed-lip breathing adopted spontaneously.

Why breathlessness is under-reported

People with emphysema adjust their lives downwards over years — taking the lift, driving instead of walking, shopping less often — and then report that they are “fine” because they no longer do whatever makes them breathless. Asking what they have stopped doing is far more informative than asking how breathless they are.

Warning signs

Diagnosis

Why diagnosis matters

A firm diagnosis opens the door to the interventions that change outcomes — smoking cessation, pulmonary rehabilitation, appropriate inhaled therapy and, in selected patients, lung volume reduction — and to screening for treatable co-morbidities and an action plan. It also stops the person attributing progressive disability to age.²

How is it diagnosed?

Diagnosis rests on post-bronchodilator spirometry showing airflow obstruction — FEV₁/FVC below 0.7 or below the lower limit of normal — in someone with relevant symptoms and exposures. Spirometry alone does not distinguish emphysema from chronic bronchitis; imaging and gas transfer do.

Radiology

High-resolution CT demonstrates and characterises the emphysema — centrilobular (typically upper-zone, smoking-related), panlobular (lower-zone, alpha-1 related) or paraseptal — and identifies bullae. CT is also what determines whether the disease is heterogeneous enough for lung volume reduction, and screens for lung cancer and coronary calcification at the same time.

Lung function

Full lung function typically shows hyperinflation with a raised residual volume and total lung capacity, and reduced gas transfer (low DLCO) — the latter being the measurement that most distinguishes emphysema from chronic bronchitis. Field exercise testing, usually the six-minute walk test with oximetry, quantifies functional capacity and detects exertional desaturation that resting measurements miss entirely.

Investigations for related conditions

An alpha-1 antitrypsin level is measured at least once. Assessment covers cardiovascular disease, osteoporosis, and low-dose CT lung-cancer screening in eligible patients. Echocardiography is used where pulmonary hypertension or right heart strain is suspected, and arterial or capillary blood gases where oxygen therapy is being considered.

Management

Management and goals

Emphysema is not reversible, so the goals are to stop progression, reduce breathlessness, maintain and rebuild exercise capacity, prevent and manage exacerbations, and preserve independence. Framing this honestly — the destroyed alveoli will not come back, but almost everything limiting the person today is modifiable — is more useful than either false optimism or fatalism.

Smoking cessation

The only intervention proven to slow the rate of decline. Benefit accrues at any age and at any stage, and cessation support combining pharmacotherapy with behavioural support is offered actively rather than mentioned.

Pulmonary rehabilitation

The intervention with the largest effect on symptoms. Pulmonary rehabilitation produces clinically significant improvements in breathlessness, fatigue, emotional function and sense of control, exceeding what any inhaler achieves.³ It works largely by improving peripheral muscle efficiency and breathing pattern rather than by changing lung function — which is why spirometry is a poor way to judge its success.

Inhaled therapy and vaccination

Long-acting bronchodilators (LAMA and/or LABA) reduce hyperinflation and breathlessness and improve exercise tolerance, with inhaled corticosteroids added in exacerbation-prone, eosinophilic patients. Vaccination against influenza, pneumococcus, COVID-19 and RSV is standard.

Long-term oxygen therapy

In chronic severe resting hypoxaemia, continuous oxygen improves survival — established by the Nocturnal Oxygen Therapy Trial, in which continuous therapy was superior to nocturnal-only.⁴ Importantly, this does not extend to milder disease: in patients with COPD and only moderate resting or exercise-induced desaturation, long-term supplemental oxygen produced no benefit in time to death or hospitalisation, quality of life or exercise capacity.⁵ Oxygen is a treatment for hypoxaemia, not for breathlessness, and saying so prevents a great deal of misplaced expectation.

Lung volume reduction

In selected patients with severe, heterogeneous, upper-lobe-predominant emphysema and low exercise capacity, lung volume reduction surgery improved exercise capacity and survival compared with medical therapy in the National Emphysema Treatment Trial.⁶ Bronchoscopic lung volume reduction with endobronchial valves is now the more commonly used approach: Zephyr valves significantly improved lung function, exercise capacity and quality of life in heterogeneous emphysema without collateral ventilation,⁷ and the Spiration valve system produced comparable benefit.⁸ Careful selection on CT and collateral ventilation assessment is what determines success.

Identifying deterioration and advanced disease

Rising exacerbation frequency, weight loss, falling exercise capacity, new hypoxaemia or right heart failure indicate progression. Transplant assessment is considered in advanced disease in suitable candidates, and advance care planning is opened early rather than in a crisis.

Medications

Medications for emphysema

Inhaled therapy is the cornerstone, aimed at reducing hyperinflation. Roflumilast or long-term azithromycin are used in selected frequent exacerbators. There is no drug that restores destroyed alveoli.

Alpha-1 antitrypsin augmentation

In severe inherited deficiency, intravenous augmentation with purified alpha-1 antitrypsin significantly slowed the progression of emphysema measured by CT lung density, although effects on clinical outcomes remain less certain.⁹ It is a specialist therapy for a defined group — verify current TGA and PBS status.

Correct use of medications

Inhaler technique is the strongest determinant of benefit and is checked at every visit, with a spacer used for pressurised metered dose inhalers. Poor inspiratory flow is common in advanced emphysema and makes dry powder devices less suitable — device choice should follow the patient’s inspiratory capacity rather than formulary habit. A change of device without retraining reliably reduces effectiveness.

Multi-system manifestations

Skeletal muscle

Quadriceps wasting and weakness occur early and independently of lung function, and matter enormously: quadriceps strength predicts mortality in moderate to severe COPD.¹⁰ This is the single most compelling argument for exercise training, and it means a leg press is as much a respiratory intervention as an inhaler.

Cardiovascular

Ischaemic heart disease, heart failure and arrhythmia are common and frequently contribute to the breathlessness attributed entirely to the lungs. Hyperinflation itself impairs cardiac filling, so reducing it improves cardiac output as well as ventilation.

Pulmonary vasculature and right heart

Chronic hypoxaemia and capillary bed destruction produce pulmonary hypertension and, ultimately, cor pulmonale with peripheral oedema and raised jugular venous pressure — a marker of advanced disease and poor prognosis.

Bone

Osteoporosis is highly prevalent, driven by smoking, inactivity, low body weight, systemic inflammation and corticosteroid exposure. Vertebral fracture worsens the mechanics of an already compromised chest wall.

Nutrition and body composition

The low-weight, muscle-depleted emphysematous phenotype carries a worse prognosis, and unintentional weight loss is an ominous sign. Eating is itself effortful when the diaphragm is flattened and the stomach presses upwards, so smaller frequent energy-dense meals work better than three large ones.

Mood and cognition

Anxiety, panic and depression are common and independently worsen breathlessness, adherence and outcomes. Breathlessness-related panic is specifically treatable, and treating it improves function more than any change in medication.

Living with emphysema

Pacing and energy conservation

Planning the day around a finite energy budget, breaking tasks into stages, sitting for tasks that can be done seated, and using breathing control before rather than after exertion. This is skilled work, not common sense, and it is taught.

Managing breathlessness

Pursed-lip breathing, forward-lean positions, a handheld fan to the face, and recognising that breathlessness is distressing but not dangerous. Understanding hyperinflation helps people accept that slowing down actually delivers more air, not less.

Staying active

The temptation is to avoid what causes breathlessness, which produces deconditioning and more breathlessness for the same task. Regular, moderate, tolerable activity — maintained lifelong, not just for the duration of a rehabilitation programme — is what preserves independence.

Nutrition

Smaller, more frequent, energy- and protein-dense meals; avoiding large meals that splint the diaphragm; and dietetic input where weight or muscle mass is falling.

Sleep

Nocturnal hypoxaemia, coexisting sleep apnoea and orthopnoea from hyperinflation all disrupt sleep. Sleeping propped up helps, and a sleep assessment is warranted where snoring, apnoea or morning headache is reported.

Travel and daily practicalities

Most people travel successfully, with an in-flight oxygen assessment where lung function is significantly impaired and advance arrangements for oxygen at the destination. Vaccinations, a current action plan, a rescue supply of medication and a written summary of the condition travel with them.

Prognosis

Emphysema is not reversible, but its trajectory is highly modifiable. Smoking cessation slows decline; pulmonary rehabilitation improves symptoms and function; long-term oxygen improves survival in severe hypoxaemia; lung volume reduction improves both function and, in selected patients, survival. Prognosis is determined less by FEV₁ alone than by the combination of lung function, exercise capacity, breathlessness, body mass index and co-morbidity — which is precisely why the interventions that improve exercise capacity and nutrition are not merely symptomatic.

Role of the physiotherapist

Physiotherapy is central to living well with emphysema, and it addresses the dominant mechanism directly. Pulmonary rehabilitation — delivered by physiotherapists — is the exercise-based intervention with the strongest evidence for reducing breathlessness and improving quality of life, and its effect on quadriceps strength has direct prognostic significance.¹⁰

Breathlessness management is the second strand: breathing retraining with pursed-lip and paced breathing, forward-lean and other positions of ease, fan therapy, pacing and energy conservation — all of which work by reducing dynamic hyperinflation or by altering the perception of effort. Inspiratory muscle training is used in selected patients with demonstrable inspiratory muscle weakness, and airway clearance where sputum coexists.

Where emphysema is severe, clearly heterogeneous between lobes and dominated by hyperinflation, the respiratory team may assess suitability for bronchoscopic lung volume reduction with endobronchial valves — and physiotherapy runs both sides of that pathway, delivering the pre-procedure rehabilitation that determines candidacy and the post-procedure programme that converts an improvement in lung mechanics into an improvement in life. Beyond that: inhaler technique review at every contact, action-plan support, exercise testing, oxygen assessment on exertion, and early recognition of deterioration.

Part 1 · References

1. O'Donnell DE, Laveneziana P. Dyspnea and activity limitation in COPD: mechanical factors. COPD 2007;4(3):225–236.
2. Yang IA, George J, McDonald CF, et al. The COPD-X Plan: Australian and New Zealand guidelines for the management of chronic obstructive pulmonary disease. Version 2.78. Brisbane: Lung Foundation Australia and Thoracic Society of Australia and New Zealand; October 2025. Available at: copdx.org.au
3. McCarthy B, Casey D, Devane D, Murphy K, Murphy E, Lacasse Y. Pulmonary rehabilitation for chronic obstructive pulmonary disease. Cochrane Database Syst Rev 2015;(2):CD003793.
4. Nocturnal Oxygen Therapy Trial Group. Continuous or nocturnal oxygen therapy in hypoxemic chronic obstructive lung disease. Ann Intern Med 1980;93(3):391–398.
5. Long-Term Oxygen Treatment Trial Research Group. A randomized trial of long-term oxygen for COPD with moderate desaturation. N Engl J Med 2016;375(17):1617–1627.
6. Fishman A, Martinez F, Naunheim K, et al. A randomized trial comparing lung-volume-reduction surgery with medical therapy for severe emphysema (NETT). N Engl J Med 2003;348(21):2059–2073.
7. Criner GJ, Sue R, Wright S, et al. A multicenter randomized controlled trial of Zephyr endobronchial valve treatment in heterogeneous emphysema (LIBERATE). Am J Respir Crit Care Med 2018;198(9):1151–1164.
8. Criner GJ, Delage A, Voelker K, et al. Improving lung function in severe heterogenous emphysema with the Spiration Valve System (EMPROVE). Am J Respir Crit Care Med 2019;200(11):1354–1362.
9. Chapman KR, Burdon JGW, Piitulainen E, et al. Intravenous augmentation treatment and lung density in severe alpha-1 antitrypsin deficiency (RAPID): a randomised, double-blind, placebo-controlled trial. Lancet 2015;386(9991):360–368.
10. Swallow EB, Reyes D, Hopkinson NS, et al. Quadriceps strength predicts mortality in patients with moderate to severe chronic obstructive pulmonary disease. Thorax 2007;62(2):115–120.

References are numbered in citation order (Vancouver/BMJ style) and were current at the time of writing. Guidelines are living documents — verify against the latest version before clinical use.