Understanding restrictive lung disease with spirometry

Restrictive patterns on spirometry are an indicator of restrictive lung disease.

According to NCBI, the overall prevalence of restrictive lung diseases – established that they can occur in several clinical stages, often involving other pathological conditions – is estimated at 3 to 6 cases per 100,000 patients with a lung disease.

But what are restrictive lung diseases exactly? How can they be treated and which categories are at risk of developing them? Let’s find out.

1. What is restrictive lung disease?

Simply put, a restrictive lung disease is a pathological condition that leads to a decrease in the volume of air that your lungs are able to hold. This is due to a reduced distensibility of the lungs which compromises lung expansion, thus reducing lung volumes and total capacity.

Asbestosis, sarcoidosis and pulmonary fibrosis are examples of restrictive lung disease.

1. Difference between restrictive lung diseases and obstructive lung diseases

Though they share some symptoms – such as shortness of breath, wheezing, cough or chest pain – restrictive lung diseases differ from obstructive lung diseases on a functional level.

Patients with a restrictive lung disease cannot fully fill their lungs with air because the lungs cannot expand properly.

In the case of obstructive lung disease – e.g. COPD or asthma – the air can enter the lungs, but there are obstructions in the airways that make it hard for patients to blow it out when they exhale.

1. Causes of restrictive lung disease

Restrictive lung diseases are more often due to conditions that cause stiffness of the lungs. There are cases, however, in which the lungs are unable to expand because of damaged nerves or stiffness of the chest muscles, that can restrict the area of the chest for the lungs to expand in.

Conditions and behavioral patterns that can lead to lung restriction are:

• Interstitial lung disease. An example of this is a condition known as idiopathic pulmonary fibrosis, or IPF, which causes scar tissue to grow inside the lungs. Scar tissue is thick and the damage can worsen with time, impairing a patient’s capability to breathe.
• Sarcoidosis, an autoimmune disease that can affect several organs in the body, most commonly the lungs and lymph glands. It leads to the formation of granulomas that alter the structure of the affected organs. This condition is more common in women, who are considered at higher risk of developing restrictive patterns compared to men.
• Scoliosis, as the spine curve can lead to breathing difficulties.
• Neuromuscular disease, such as muscular dystrophy or ALS. Such conditions can lead to muscular atrophy, that causes your muscles to waste away and weaken, making it hard for your chest cavity to expand.
• Obesity. People with high BMIs are at risk of restrictive lung diseases, as a higher amount of central obesity can lead to a decrease in lung volume.
• A history of smoking, that can lead to conditions such as IPF.

1. Diagnosis of restrictive lung disease

When patients experience symptoms such as shortness of breath and chest pain, physicians may require a series of tests in order to identify the presence of a chronic lung condition.

Testing used for the diagnosis of restrictive lung disease may include:

• Pulmonary function tests such as spirometry. Restrictive patterns in pulmonary function usually lead to decreased TLC and FVC.
• An interview with the patience, in order to obtain a thorough anamnesis about their history and past.
• Chest X-rays or CT scan of the chest.

1. Treatments for restrictive lung disease

Treatments and management of restrictive lung disease may vary depending on several factors, such as the type and stage of the condition, a patient’s family history and medical history, as well as their age and general health status.

Common treatments range from the use of expectorants and antibiotics, to inhalers, oxygen therapy, chemotherapy and lung transplant.