Restrictive Lung Disease

Restrictive vs obstructive lung disease

Lung diseases are broadly grouped by how they affect breathing on lung function tests:

Some people have both patterns, called a mixed defect. See COPD for the obstructive type.

Causes

Intrinsic: diseases of the lung tissue

The lung tissue becomes stiff from inflammation or scarring:

• Pulmonary fibrosis, including idiopathic pulmonary fibrosis
• Interstitial lung disease linked to rheumatoid arthritis, scleroderma and other autoimmune diseases
• Sarcoidosis
• Hypersensitivity pneumonitis from inhaled organic dusts
• pneumoconiosis from asbestos, silica and coal dust
• drug and radiation injury: amiodarone, methotrexate, nitrofurantoin, some chemotherapy
• after severe infection or ARDS

Extrinsic: problems outside the lung

The lungs are normal but cannot expand:

• obesity and obesity hypoventilation syndrome
• chest wall deformities: kyphoscoliosis, ankylosing spondylitis, previous chest surgery
• pleural disease: large pleural effusions, pleural thickening
• neuromuscular disease: ALS, muscular dystrophy, myasthenia gravis, spinal cord injury, diaphragm paralysis
• abdominal causes: large amounts of ascites or late pregnancy

Symptoms

• breathlessness, first with exertion, later at rest
• rapid, shallow breathing
• dry cough (especially in interstitial lung disease)
• fatigue and reduced exercise capacity
• finger clubbing in some fibrotic diseases
• with neuromuscular or chest wall causes: poor sleep, morning headaches and daytime sleepiness from low breathing at night

Diagnosis

• spirometry: shows reduced FVC with a normal or high FEV1/FVC ratio, which suggests restriction
• full lung volumes (body plethysmography): reduced total lung capacity confirms restriction
• diffusing capacity (DLCO): reduced in lung tissue disease, usually normal in chest wall causes
• chest X-ray and high-resolution CT to look for fibrosis and other changes
• oxygen levels at rest, during a walk test and overnight
• blood tests for autoimmune disease
• respiratory muscle tests and sleep studies for neuromuscular causes
• lung biopsy in selected cases

Treatment

Treatment depends on the cause:

• idiopathic pulmonary fibrosis and progressive fibrosis: antifibrotic drugs (nintedanib, pirfenidone)
• inflammatory interstitial lung disease: corticosteroids and immunosuppressants
• remove exposures: occupational dust, birds or molds, causative medicines
• obesity: weight loss and treatment of sleep-related breathing problems
• neuromuscular and chest wall disease: non-invasive ventilation (BiPAP) at night, airway clearance techniques
• pleural effusions: drainage and treatment of the cause
• for all: pulmonary rehabilitation, oxygen if levels are low, vaccinations, stopping smoking
• lung transplant for advanced lung tissue disease in suitable people

Frequently asked questions

What is restrictive lung disease?

Restrictive lung disease is a group of conditions that prevent the lungs from fully expanding, reducing the amount of air they hold. It can come from stiff lung tissue, such as pulmonary fibrosis, or from problems outside the lungs, such as obesity or scoliosis.

What is the difference between restrictive and obstructive lung disease?

In restrictive disease, the lungs cannot fill with enough air. In obstructive disease, such as COPD or asthma, air cannot flow out easily. Lung function tests distinguish them by measuring lung volumes and airflow.

What are the symptoms of restrictive lung disease?

The main symptoms are breathlessness with activity, rapid shallow breathing, a dry cough and fatigue. In neuromuscular causes, poor sleep, morning headaches and daytime sleepiness can occur.

Can restrictive lung disease be cured?

Some causes can be reversed, such as pleural effusions, drug reactions, obesity-related restriction and some inflammatory lung diseases. Fibrotic lung disease is usually not reversible, but antifibrotic medicines can slow its progression.