Doctors may classify lung conditions as obstructive lung disease or restrictive lung disease. Obstructive lung diseases include conditions that make it hard to exhale all the air in your lungs. People with restrictive lung disease have trouble fully expanding their lungs with air.
Obstructive and restrictive lung disease share the same main symptom: shortness of breath when you exert yourself.
What Is Obstructive Lung Disease?
People with obstructive lung disease have shortness of breath because it's hard for them to exhale all the air from their lungs. Because of damage to the lungs or narrowing of the airways inside the lungs, the exhaled air comes out more slowly than it should. At the end of a full exhalation, too much air may linger in the lungs.
The most common causes of obstructive lung disease are:
- Chronic obstructive pulmonary disease (COPD), which includes emphysema and chronic bronchitis
- Cystic fibrosis
Obstructive lung disease makes it harder to breathe, especially when you're exercising or otherwise being active. As your breathing rate increases, you have less time to breathe all the air out before you inhale again.
What Is Restrictive Lung Disease?
People with restrictive lung disease can't fully fill their lungs with air. Their lungs are restricted from fully expanding.
Restrictive lung disease most often results from a condition that causes stiffness in the lungs themselves. In other cases, stiffness of the chest wall, weak muscles, or damaged nerves may restrict how much your lungs can expand.
Some conditions causing restrictive lung disease are:
- Interstitial lung disease, such as idiopathic pulmonary fibrosis
- Sarcoidosis, an autoimmune disease
- Obesity, including obesity hypoventilation syndrome
- Neuromuscular disease, such as muscular dystrophy or amyotrophic lateral sclerosis (ALS)
Diagnosis of Obstructive Lung Disease and Restrictive Lung Disease
Most often, people with obstructive or restrictive lung disease see a doctor because they feel short of breath.
Doctors identify restrictive and obstructive lung diseases using pulmonary function tests. In pulmonary function testing, you blow air forcefully through a mouthpiece. As you go through various breathing exercises, a machine records the volume and flow of air through your lungs. Pulmonary function testing can show whether you have obstructive lung disease or restrictive lung disease, as well as how serious they are.
Imaging tests are almost always part of the process of diagnosing restrictive and obstructive lung disease. These may include:
- Chest X-rays
- Computed tomography (CT scan) of the chest
Sometimes, your doctor may recommend a bronchoscopy to help them figure out what's causing obstructive or restrictive lung disease. In a bronchoscopy, your doctor uses an endoscope (a flexible tube with a camera and tools on its tip) to look inside your airways and take samples of lung tissue (biopsy).
Symptoms of Obstructive and Restrictive Lung Disease
Obstructive lung disease and restrictive lung disease cause shortness of breath. In their early stages, you get short of breath only when you exert yourself. If the underlying lung condition gets worse, it might happen with very little activity, or even when you're at rest.
Cough is a common symptom for both types of lung diseases. Usually, the cough is dry or brings up white sputum (mucus). People with chronic bronchitis, a type of obstructive lung disease, may cough up larger amounts of colored sputum.
Treatments for Obstructive Lung Disease
Obstructive lung disease treatments work by helping to open narrowed airways. Your airways may be narrowed because you have spasms in the smooth muscles that line their walls. These are called bronchospasms.
Medicines that relax these smooth muscles and improve airflow are called bronchodilators, and are inhaled. These include:
- Albuterol (Proventil HFA, Ventolin HFA, AccuNeb, ProAir HFA)
- Ipratropium (Atrovent)
- Formoterol (Foradil)
- Salmeterol (Serevent)
- Tiotropium (Spiriva)
- Combined medications like Advair, Anora Ellipta, Combivent Respimat, DuoNeb, and Trelegy Ellipta, which include a bronchodilator
Theophylline (Theo-Dur and other brand names) is a rarely used bronchodilator taken as an oral tablet.
Inflammation also contributes to airway narrowing in obstructive lung disease. Inflamed airway walls may be swollen and filled with mucus, obstructing airflow. Various medicines help reduce inflammation in obstructive lung disease, including:
- inhaled corticosteroids (Flovent, Pulmicort, Advair, QVAR, Alvesco, and others)
- oral corticosteroids (prednisone and others)
- montelukast (Singulair)
A program of regular exercise will improve symptoms of breathlessness in virtually all people with obstructive lung disease. Oxygen therapy may be necessary for some people.
In severe cases of end-stage, life-threatening obstructive lung disease, lung transplantation can be considered as a treatment option.
Treatments for Restrictive Lung Disease
Few medicines are available to treat most causes of restrictive lung disease.
The FDA has approved two drugs, Esbriet (pirfenidone) and Ofev (nintedanib)to treat idiopathic pulmonary fibrosis. They act on several pathways that may be involved in causing scars to your lung tissue. Studies show both medications can slow down restrictive lung disease, as measured by pulmonary function tests.
If you have restrictive lung disease caused by long-lasting inflammation, your doctor may prescribe medicines that suppress your immune system, like:
You might also need oxygen therapy. Mechanical breathing assistance may help some people who have breathing problems due to restrictive lung disease. Non-invasive positive pressure ventilation (BiPAP) uses a tight-fitting mask and a pressure generator to help you breathe. BiPAP can help people with obesity hypoventilation syndrome and some nerve or muscle conditions that cause restrictive lung disease.
If you have very serious restrictive lung disease (such as idiopathic pulmonary fibrosis), you may need a lung transplant.
Regular exercise improves shortness of breath and quality of life in almost everyone with restrictive lung disease.