What are Restrictive Lung Diseases?
Restrictive lung diseases are chronic medical conditions that limit the ability of the lungs to expand during inhalation causing reduced lung capacity or volume that increases an individual’s breathing rate to meet the oxygen demand. In most cases, they are found to be progressive and worsen over time. They are often manageable with medications and an exercise regimen but most cases of restrictive lung diseases are not curable.
Types of Restrictive Lung Diseases
Restrictive lung diseases are commonly divided into two types, depending on whether their cause is intrinsic or extrinsic.
- Intrinsic restrictive lung disease causes internal abnormalities leading to inflammation, stiffening, and scarring of the lung tissues.
- Extrinsic restrictive lung disease is caused by complications with structures or tissues outside of the lungs, including neurological conditions. External factors that cause extrinsic restrictive lung disease are often associated with damaged nerves, weakened muscles, or stiffening of chest wall tissues.
Causes of Restrictive Lung Diseases
Some of the causes of intrinsic restrictive lung disease may include:
- Interstitial lung disease
- Idiopathic pulmonary fibrosis
- Acute respiratory distress syndrome
Some of the causes of extrinsic restrictive lung disease may include:
- Pleural effusions
- Obesity hypoventilation syndrome
- Myasthenia gravis
Symptoms of Restrictive Lung Diseases
The symptoms of restrictive lung diseases may include:
- Shortness of breath
- Chronic cough
- Chest pain
- Weight loss
- Tachypnea (rapid respiratory rate)
Diagnosis of Restrictive Lung Diseases
To arrive at an accurate diagnosis, your doctor will review your symptoms and medical history, perform a physical examination, and order certain tests and imaging, including:
- Forced vital capacity (FVC) test: In this test, the patient inhales as much air as possible and exhales with as much force as possible. If you have an FVC value of less than or equal to 80 per cent of what is anticipated, it can be a sign of restrictive lung disease.
- Forced expiratory volume in 1 second (FEV1) test: This test measures the total amount of air that can be forcibly exhaled during the first second of the FVC test. Healthy people, in general, expel around 75 to 85 per cent during this time. The FEV1 value is normal to minimally decreased in restrictive lung diseases.
- FEV1 to FVC ratio test: This test compares the amount of air expelled during the first second of exhalation (FEV1) to the total amount of air exhaled during an FVC test. The ratio is often normal or increased if you have restrictive lung disease.
- Total lung capacity (TLC): This test is calculated by adding the volume of air remaining in the lungs after exhalation with the FVC. TLC value is found to be decreased if you have a restrictive lung disease.
- Chest x-ray: To create images of the entire lung and chest area for evaluation.
- CT scans: To create detailed images of the lung and chest area than x-rays can reveal.
- Bronchoscopy: A flexible tube with a camera is passed through the mouth or nose into the airways of the lung for evaluation.
Treatment of Restrictive Lung Diseases
There are many treatment options to treat restrictive lung diseases. Your doctor will determine the kind of treatment you need based on the type and severity of the restrictive lung disease you have. In general, the main objective of the treatment is to make breathing easier and slow the progression of the disease. Any of the following methods may be used for treating restrictive lung disease:
- Inhalers: Inhalers are handheld devices that can deliver quick blasts of medications or corticosteroids into your bronchial tubes to relax them. You may need this method of treatment if you have a type of restrictive lung disease known as interstitial lung disease that causes inflammation of the air sacs in your lungs.
- Immunosuppressants: Some types of restrictive lung diseases stem from autoimmune disorders. An autoimmune disease causes the body’s immune system to mistakenly attack its own tissues. Immunosuppressants act by blocking the action of the body’s immune system.
- Expectorants: Certain kinds of restrictive lung diseases, such as pneumoconiosis, can cause accumulation of mucus and phlegm in your airways making breathing difficult. Expectorants help in clearing your airways from mucus and aid in breathing.
- Oxygen therapy: You may need oxygen therapy if your restrictive lung disease is limiting the amount of oxygen reaching the lungs through your bloodstream. This treatment works by pumping oxygen from a portable tank through a tube to a mask worn over your nose or mouth.
- Pulmonary rehabilitation: This treatment can treat restrictive lung disease and other lung-related health problems and involves teaching management of the condition through breathing techniques, specific exercise regimen, nutrition, etc.
- Lung transplant: This surgical treatment is reserved only for serious restrictive lung disease cases and involves transplanting new lungs from an organ donor who has recently expired.