Understanding pulmonary fibrosis: from symptoms to treatments 

Pulmonary fibrosis, also known as lung fibrosis, refers to a group of chronic (long-term) conditions that damage lung tissue. 

They are called restrictive lung conditions as they restrict the ability of the lungs to fully expand when you breathe in and out. This is in contrast to obstructive lung conditions that narrow the airways, such as asthma and COPD. 

The most common type of pulmonary fibrosis is called idiopathic pulmonary fibrosis (IPF) and it affects 15–20 people in every 100,000 in the UK. 

Here, we will explore the pulmonary fibrosis risk factors, causes, symptoms and treatments.

What happens in pulmonary fibrosis?

Your lung tissue comprises tiny air sacs called alveoli that sit at the end of branches of your airways called bronchioles. It is in these alveoli where gases are exchanged when you breathe. 

Oxygen passes through your alveoli to enter your bloodstream and carbon dioxide passes out of your bloodstream into your alveoli and is then exhaled. 

The space between your alveoli and the blood vessels that supply them is called the interstitium. The interstitium is made of connective tissue. In pulmonary fibrosis, this connective tissue becomes inflamed, scarred and thickened – this is called fibrosis. 

As a result of fibrosis, the lungs become less elastic, harder and stiffer, which makes it difficult to breathe. This, in turn, makes it more difficult to deliver oxygen to your organs and tissues. 

Types of pulmonary fibrosis 

Pulmonary fibrosis can be broadly divided into two groups: idiopathic pulmonary fibrosis and non-idiopathic pulmonary fibrosis. 

Idiopathic pulmonary fibrosis is the most common type of pulmonary fibrosis for which there is no known cause. 

In non-idiopathic pulmonary fibrosis, a known cause can be identified. These include connective tissue diseases (eg systemic sclerosis), autoimmune diseases (eg rheumatoid arthritis), and diseases that result from environmental irritants (pneumoconiosis). Pneumoconiosis includes silicosis, which is caused by inhaling silica, and asbestosis, which is caused by inhaling asbestos.

In rare cases, ILD can be the result of a severe side effect to a drug, such as the antibiotic nitrofurantoin, and certain immunosuppressant and chemotherapy drugs such as methotrexate.

Risk factors for pulmonary fibrosis 

Pulmonary fibrosis is more common in people over the age of 50 and most commonly affects people in their seventies. Your risk is also higher if you smoke or work in an environment that exposes you to environmental toxins, such as asbestos and silica dust, which can irritate your lungs. 

If you keep pigeons or other birds, their feathers or droppings can trigger hypersensitivity pneumonitis (a type of ILD), which can also lead to pulmonary fibrosis. 

More recently, growing evidence suggests a link between COVID infection and later development of pulmonary fibrosis. 

Your genetics may also affect your risk of idiopathic pulmonary fibrosis – around one in 20 individuals with pulmonary fibrosis have a family member with the same condition. 

Symptoms of pulmonary fibrosis

In pulmonary fibrosis, the main symptoms are breathlessness that gradually gets worse, a persistent dry cough, fatigue, reduced appetite and swollen, rounded fingers (clubbed fingers). 

In non-idiopathic pulmonary fibrosis, you will also have symptoms caused by the underlying disease. For example, if you have rheumatoid arthritis, you will experience joint pain, swelling and tenderness, while if you have systemic sclerosis, you may experience reduced flexibility and movement of your fingers.

Diagnosing pulmonary fibrosis

If you are experiencing breathlessness that is not improving or is getting worse, or if you have had a persistent cough for three weeks or more, you should see your GP. 

They will ask you about your symptoms and medical history and may listen to your breathing using a stethoscope. 

Depending on your symptoms, they may refer you for further tests, including blood tests to check for certain diseases and/or exposure to environmental toxins. Your doctor may also refer you for lung function tests and a chest X-ray. 

If signs of pulmonary fibrosis are detected on your chest X-ray, you will be referred for a CT scan of your lungs to confirm the diagnosis. 

If a clear diagnosis still cannot be reached using these tests, your doctor may recommend a bronchoscopy. This involves passing a thin, flexible telescope-like device with a light and camera on the end (bronchoscope) into your airways. This will allow them to look for abnormal tissue and, if needed, collect a tissue sample (biopsy).

Treating pulmonary fibrosis 

There is no cure for idiopathic pulmonary fibrosis and the scarring that results from the disease is permanent. However, there are medications that can slow the progression of the disease and supportive treatments that can help manage your symptoms and improve your quality of life. 

Idiopathic pulmonary fibrosis 

The medications nintedanib and pirfenidone reduce lung fibrosis and are used to slow down idiopathic pulmonary fibrosis. 

Supportive treatments include respiratory physiotherapy, regular exercise, support to lose excess weight and home oxygen therapy.

Home oxygen therapy can help you manage fatigue and, therefore, continue with your daily activities. It is usually delivered via a nasal cannula, that is, a tube that sits in your nostrils, or via a mask that covers your nose and mouth. Depending on your needs, the tube will be attached to an oxygen concentrator, large oxygen cylinder or portable cylinder.

Your doctor will also recommend a programme of pulmonary rehabilitation, where you will be advised on how to improve your exercise tolerance and lung function, and how to better manage your breathing.

You will also be advised to have your annual flu vaccination and to receive one dose of the pneumonia vaccine.

Non-idiopathic pulmonary fibrosis 

For non-idiopathic pulmonary fibrosis, similar supportive treatments as provided for idiopathic pulmonary fibrosis can be used. 

Steroid medication may also be prescribed to help reduce inflammation. Other medications will vary depending on the underlying cause of your pulmonary fibrosis. 

For example, if pulmonary fibrosis is caused by an environmental agent, avoiding exposure will help, while if it is caused by rheumatoid arthritis, your doctor may recommend anti-inflammatory medications, biologics and/or disease-modifying antirheumatic drugs (DMARDs). 

Pulmonary fibrosis complications and outlook

Pulmonary fibrosis increases the risk of airway infections (eg bronchitis) and chest infections (eg pneumonia). 

It can also lead to respiratory failure where your lung function dramatically reduces. As a result, your dependence on oxygen therapy will increase. 

Pulmonary hypertension is another complication of pulmonary fibrosis. This refers to high blood pressure in the blood vessels that supply oxygen-rich blood to the lungs. 

In pulmonary fibrosis, pulmonary hypertension occurs because the heart is forced to work harder to continue to supply blood to the lungs due to scar tissue in the interstitium of the lungs. Over time, pulmonary hypertension weakens the heart and can lead to heart failure. 

How quickly the pulmonary fibrosis progresses varies from one individual to the next, with some rapidly declining and others experiencing periods of stability. 

Without treatment, the life expectancy for idiopathic pulmonary fibrosis is two and a half to five years. However, with proper treatment, individuals with idiopathic pulmonary fibrosis can live for significantly longer.