Obstructive vs. Restrictive Lung Diseases: Causes and Treatment

There are two types of lung diseases: obstructive lung disease and restrictive lung disease. Both types can cause symptoms like shortness of breath, but a key difference is when you feel like you’re having trouble breathing. Obstructive lung diseases like asthma and chronic obstructive pulmonary disorder (COPD) cause more trouble when you’re exhaling air. Restrictive lung diseases such as pulmonary fibrosis make it harder to inhale air.

The diagnosis and treatment for obstructive vs. restrictive lung diseases depend on the cause but can include chest imaging and medications that help open up or clear the airways.  

This article will go over obstructive and restrictive lung disease causes and symptoms, how each condition is diagnosed, and the treatments for obstructive and restrictive lung disease. 

Obstructive Lung Disease

Obstructive lung diseases happen when there is an obstruction in the air passages that causes slow and shallow exhalation. Obstruction can occur when inflammation and swelling cause the airways to become narrowed or blocked, making it harder to expel air from the lungs.

The block means that there’s an abnormally high volume of air being left in the lungs (i.e., increased residual volume). The trapped air and lung hyperinflation are changes that contribute to worsening respiratory symptoms.

The following lung diseases are categorized as obstructive:

• Chronic obstructive pulmonary disease (COPD) is a chronic and progressive inflammatory disease in the lungs. It causes wheezes, phlegm, and shortness of breath.
• Chronic bronchitis is inflammation and irritation that causes symptoms like wheezing and shortness of breath, and sometimes a squeaky sound with breathing. It’s usually caused by long-term exposure to irritating substances like cigarette smoke or toxins at work. 
• Asthma is a chronic lung disease that can make it hard to breathe. Symptoms can be triggered or made worse by pollen and other irritants.
• Bronchiectasis is a chronic problem when structures in the lungs (bronchi and bronchioles) get too wide. It can happen in people with other lung diseases like cystic fibrosis. It can cause symptoms like wheezing, chronic cough, and thick mucus.
• Bronchiolitis (also called “popcorn lung”) is a condition that’s caused by toxic exposures that damage the lungs. It can cause coughing and shortness of breath.
• Cystic fibrosis is an inherited disorder caused by a faulty gene that causes too much mucus to be made. CF causes breathing problems that can be life-threatening.

Restrictive Lung Disease

Restrictive conditions cause difficulty in filling the lungs with air during inhalation. Restrictive lung diseases cause a reduced total lung capacity.

Restrictive lung diseases can be caused by intrinsic, extrinsic, or neurological factors.

Intrinsic Restrictive Lung Diseases

Intrinsic restrictive disorders occur due to restriction in the lungs (often a "stiffening") and include:

• Pneumonia is an infection of the lungs that’s caused by bacteria, viruses, or fungi. It can cause trouble breathing and a cough.
• Pneumoconiosis is a group of lung diseases that happen when dust from substances like asbestos) gets inhaled and damages the lungs. It can cause phlegm and cough.
• Acute respiratory distress syndrome (ARDS) is a lung condition where there is a low level of oxygen in the blood (hypoxemia). It causes symptoms like shortness of breath, fast breathing, confusion, drowsiness, and bluish-colored hands and feet.
• Eosinophilic pneumonia is a rare kind of pneumonia that happens when a lot of white blood cells (eosinophils) build up in the lungs. It can cause a fever and shortness of breath.
• Tuberculosis is a lung disease caused by bacteria. It can cause a cough and blood-tinged phlegm, as well as night sweats.
• Sarcoidosis is a rare, whole-body inflammatory disease that causes cells called granulomas to build up in the body, including in the lungs. It can cause a dry cough and chest pain.
• Pulmonary fibrosis and idiopathic pulmonary fibrosis are rare lung diseases that cause the tissue of the organs to be thick and scarred. It leads to the progressive loss of function of the lungs, which makes it harder and harder to breathe.
• Lobectomy and pneumonectomy are surgeries that can be used to treat lung cancer. 

Extrinsic Restrictive Lung Diseases

Extrinsic restrictive disorders start outside of the lungs and can be caused by: 

• Scoliosis (abnormal curve of the spine) 
• Obesity
• Pleural effusion (fluid in the space around the lungs) 
• Malignant tumors (e.g., cancer) 
• Ascites (fluid buildup in the abdomen) 
• Pleurisy (fluid in the lungs) 
• Rib fractures

Neurological Restrictive Lung Diseases

Neurological restrictive lung diseases are caused by disorders of the central nervous system that affect the body movements needed to draw air into the lungs.

Common causes of neurological restrictive lung diseases include:

• Paralysis of the diaphragm
• Guillain-Barré syndrome (an autoimmune disorder that affects the brain and spine) 
• Myasthenia gravis (an autoimmune disorder that affects the muscles) 
• Muscular dystrophy (a group of inherited disorders that cause muscle weakness and wasting) 
• Amyotrophic lateral sclerosis (ALS or Lou Gehrig's Disease) (a progressive, degenerative neurological disorder that affects nerve cells that control movement) 

Symptoms

There can be a significant overlap in symptoms between obstructive and restrictive lung diseases, which is why pulmonary function tests are often needed to make a diagnosis.

Symptoms shared by both obstructive and restrictive conditions include:

• Dyspnea (shortness of breath)
• Persistent cough
• Tachypnea (rapid respiratory rate)
• Anxiety
• Unintentional weight loss (due to the increased energy needed to breathe)

Obstructive Symptoms

With obstructive lung disease, a person may have difficulty expelling all of the air from the lungs. This often worsens with activity. When their respiratory rate increases, it gets harder to blow out all of the air in the lungs before taking the next breath. Narrowing of the airways can cause wheezing, as well as increased mucus (sputum) production.

Restrictive Symptoms

With restrictive lung disease, a person may feel like it is hard to take a full breath. The feeling can even cause anxiety at times. With extrinsic lung disease, a person may change positions trying to find one that makes it easier to breathe.

Diagnosis

A provider can talk to you about your medical history and do an exam (like listening to your breath) to try to diagnose the cause of obstructive or restrictive lung disease. Pulmonary function tests and imaging tests are also useful because they can help your provider figure out what condition (or conditions) you may have.

Pulmonary Function Tests

Spirometry is a common test used to see how well your lungs are functioning. It measures how much air you inhale and how much and how quickly you exhale. The test can be helpful in telling the difference between obstructive and restrictive lung diseases, as well as seeing how severe the disease is. 

Here’s what pulmonary function tests look at: 

• Forced vital capacity (FVC): Forced vital capacity measures the amount of air you can breathe out forcefully after taking as deep a breath as you can. 
• Forced expiratory volume in one second (FEV1): This test measures the total amount of air that can be forcibly exhaled in the first second of the FVC test. Healthy people generally expel around 75% to 85%. FEV1 is lower in obstructive lung diseases and normal to only a little lower in restrictive lung diseases.
• FEV1/FVC ratio: The ratio of FEV1 to FVC measures the amount of air a person can forcefully exhale in one second relative to the total amount of air they can exhale. The ratio is lower in obstructive lung disorders and normal in restrictive lung disorders. In an adult, a normal FEV1/FVC ratio is 70% to 80%; in a child, a normal ratio is 85% or greater. The FEV1/FVC ratio can also be used to figure out the severity of obstructive lung disease.²
• Total lung capacity (TLC): Total lung capacity (TLC) is calculated by adding the volume of air left in the lungs after breathing out (the residual volume) to the FVC. TLC is normal or higher in obstructive defects and lower in restrictive ones. In obstructive lung diseases, air is left in the lungs (air trapping or hyperinflation), causing a TLC increase.
  

There are other types of pulmonary function tests that providers can use: 

• Lung plethysmography estimates how much air is left in the lungs after expiration (functional residual capacity). It can be helpful when there is an overlap with other pulmonary function tests because it shows how much air is left in the lungs (residual capacity). This is referred to as a measure of the compliance of the lungs. With restrictive airway disease, the lungs are often "stiffer" or less compliant.
• Diffusing capacity (DLCO) measures how well oxygen and carbon dioxide can diffuse between alveoli (the tiny air sacs) and capillaries (small blood vessels) in the lungs. The number may be low in some restrictive lung diseases (for example, pulmonary fibrosis) because the membrane is thicker; it may be low in some obstructive diseases (for example, emphysema) because there is less surface area for this gas exchange to take place.

Obstructive and Restrictive Lung Patterns

Laboratory Tests

Lab tests can help your provider gauge how severe lung disease is but they are not helpful at showing whether it’s obstructive or restrictive. 

Here are a few examples of what tests might show:

• A measure of the oxygen content in the blood (oximetry) is often low in both restrictive and obstructive lung disease. 
• Arterial blood gases may show a low oxygen level and, sometimes a high carbon dioxide level (hypercapnia). With chronic lung disease, hemoglobin levels are often high in an attempt to carry more oxygen to the cells of the body.

Imaging Studies

If the underlying condition is something like pneumonia or a rib fracture, imaging tests like a chest X-ray or chest computed tomography (CT) scan may help a provider see if the lung disease is obstructive or restrictive.

Procedures

Bronchoscopy is a test where a provider uses a lighted tube with a camera on it to look in your mouth and down into the large airways. Like imaging studies, it can sometimes help diagnose the underlying condition that’s causing obstructive or restrictive lung disease. 

Lung Disease Treatment

The treatment options are different for obstructive and restrictive lung diseases and depend on what the underlying cause is.

Obstructive Lung Disease

Obstructive lung diseases such as COPD and asthma are often treated with medications that dilate the airways (bronchodilators) and help with symptoms. Inhaled or oral steroids are also frequently used to reduce inflammation.

Here are some specific obstructive lung disease treatments based on the underlying condition: 

• Chronic obstructive pulmonary disease (COPD) usually needs to be treated with medications and lifestyle changes.
• Chronic bronchitis is treated with medications to relax the airways, lifestyle changes, and pulmonary rehab.
• Asthma can be treated with medications like inhaled steroids.
• Bronchiectasis usually needs to be treated with lifestyle approaches, medications, and preventing infections.
• Bronchiolitis can’t be cured but the symptoms can be managed with therapy and medication. Sometimes, a lung transplant is considered.
• Cystic fibrosis can’t be cured but there are treatments that can help manage symptoms and prevent complications.

Restrictive Lung Disease

Treatment options for restrictive lung diseases are more limited.

Depending on the type and cause, restrictive lung disease may need to be treated with antibiotics, inhalers, chemotherapy, expectorants (type of cough medicine), lung transplantation, and oxygen therapy.

Here are some specific restrictive lung disease treatments based on the underlying condition:

• Pneumonia can be treated with medications like antibiotics or antifungals depending on the cause.
• Pneumoconiosis usually needs to be treated with lifestyle changes, especially avoiding substances that harm the lungs (like smoke). 
• Acute respiratory distress syndrome is life-threatening and needs medical treatment like oxygen therapy, usually in the hospital.
• Eosinophilic pneumonia needs to be treated based on the underlying cause, like antibiotics for an infection.
• Tuberculosis needs to be treated with medication, including antibiotics.
• Sarcoidosis needs to be treated with medications like steroids, immunosuppressants, and anti-inflammatories.
• Pulmonary fibrosis usually needs to be treated with special medications called antifibrotics, and in some cases, a lung transplant.

With extrinsic restrictive lung disease, treatment of the underlying cause (e.g., pleural effusion or ascites) can help with symptoms. This is also true for intrinsic restrictive lung diseases like pneumonia.

Other conditions can be harder to treat. For example, until recently, there was little that could be done to treat idiopathic pulmonary fibrosis. Today, there are drugs available that can reduce the severity.

Supportive treatment for restrictive and obstructive lung diseases can include supplemental oxygen, noninvasive ventilation (such as CPAP or BiPAP), or mechanical ventilation. 

Pulmonary rehabilitation can be helpful for some people—for example, those living with COPD and those who have had lung cancer surgery. When the condition causing restrictive or obstructive lung disease is severe and there is too much damage to the lungs, a lung transplant might be the recommended treatment.

Summary

Obstructive and restrictive lung diseases have some similar symptoms but different causes and treatments. It’s possible that a lung condition can go from being obstructive to being restrictive. If you have lung disease symptoms, your provider will figure out what the underlying cause is and recommend the appropriate treatment to help improve your quality of life and prevent complications.