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Idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) belongs to the large family of interstitial lung diseases. The disease causes irreversible and progressive lung scarring for reasons still not understood. The term idiopathic refers to the fact that the causes of this pulmonary disease are unknown. IPF represents approximately 50% of all diagnosed types of pulmonary fibrosis.

IPF slowly destroys and scars the lungs of people with this disease. For a long time, it was thought that the lung tissue scarring that characterizes IPF was the result of a chronic inflammatory mechanism. More recent data indicate that the lungs of people with IPF do not show the usual signs of inflammation. Instead, it is thought that the lung scarring in IPF is the result of another more subtle mechanism that distinguishes IPF from (non-idiopathic) pulmonary fibrosis.

In people with (non-idiopathic) pulmonary fibrosis, the cause of the scarring is known. For example, with long-term exposure to fine mineral particles, the particles can lodge deep in the lungs and destroy the alveoli, the small clusters of air sacs at the bottom of the lungs that allow oxygen (O2) to enter the bloodstream and carbon dioxide (CO2) to leave. The body perceives these minerals as aggressors and uses inflammation as a defence mechanism to protect itself. Scarring, in the form of stiff, thick tissue, is the ultimate outcome of the inflammatory process that repairs the damage caused to the alveoli.


In people with IFP, this mechanism is slightly different because there is no inflammatory process to explain the development of scarring in the lungs, as in the case of pulmonary fibrosis. What, then, explains the scarring that occurs in the lungs of people with IPF? In brief, researchers suspect that an unknown aggressor damages the edges of the small alveolar sacs and that the scarring is the result of an imbalance in the repair process of these small sacs. Hence, the development of scarring without an inflammatory process. It is this last point that distinguishes IPF from pulmonary fibrosis and is useful in finding treatments specific to each.


It is not known what causes IPF to develop. However, studies of people with the disease seem to indicate the presence of certain risk factors. In fact, smoking, exposure to environmental pollutants and lung infections are features often seen in individuals with IFP.

Moreover, a history of gastroesophageal reflux is often seen in IPF patients although the connection between these two conditions is not well understood. Genetic factors might be involved in the development of IPF. In fact, cases of familial idiopathic pulmonary fibrosis are occasionally encountered.

Signs and symptoms

The symptoms of IPF are not very specific and can resemble those of other types of pulmonary fibrosis and even other pulmonary diseases. They include:

  • unusual shortness of breath during physical exertion that becomes permanent
  • dry cough
  • loss of endurance
  • loss of appetite 
  • fatigue
  • weight loss
  • diffuse pain in the chest

This may be followed by:

  • diminished tolerance to daily activities
  • shortness of breath without physical effort, while eating, talking or simply resting
  • cyanosis (bluish colour of the lips, nails and sometimes of the skin, caused by insufficient oxygenation of the tissues)
  • distortion of the fingers (digital hippocratism)

People with IPF may also experience episodes of acute exacerbation characterized by a period of rapid deterioration with worsening of symptoms.


Diagnosing IPF can be a long and arduous process because the symptoms resemble those of some heart diseases and other, more common lung diseases.

At the outset, lung function tests and a chest X-ray are the examinations that can direct the physician to a diagnosis of IPF. Individuals with IPF will always have an abnormal chest X-ray. However, this tool lacks accuracy and cannot provide an explanation for these abnormalities. Further investigative tests are required to establish an accurate diagnosis. Lung function tests involve breathing into various devices. The information collected provides objective data on the health of the lungs. Additionally, a walking test can be performed to measure a patient’s exercise tolerance.

Next, a computerized axial tomography (CAT/CT) scan will be required. This accurate imaging tool allows for 3D visualization of the lungs using a long series of X-ray images to confirm the diagnosis of IPF and to evaluate the extent of the disease. On a CAT scan, IPF is recognizable by, among other things, changes in the lung resembling a honeycomb. If the diagnosis is not clear on the CAT scan, a lung biopsy can be considered.

High-resolution  CAT scan of the lungs of a patient with IPF. The main feature is the formation of “honeycombs” areas shown by the red arrows.

Other tests, such as transthoracic echocardiography, can also be done to detect the presence of pulmonary hypertension.


Treatment of IPF is a challenge for specialists. At present, there is no cure for the disease and available treatments are, instead, aimed at slowing disease progression and managing the symptoms. Prescribed treatments include the following:

  • anti-inflammatories
  • antifibrotic agents
  • oxygen
  • etc.

In some cases, oxygen therapy and participation in pulmonary education and rehabilitation programs may be recommended.

In managing IPF, it is also very important to address all comorbidities (co-existing health problems) that might be present, for example:

  • gastroesophageal reflux
  • heart disease
  • chronic obstructive pulmonary disease (COPD – chronic bronchitis and emphysema)
  • sleep apnea

Research into possible treatments has intensified and is rapidly evolving. To date there are two medications, pirfenidone and nintenadib, that have shown therapeutic efficacy in slowing the disease. Pirfenidone has both antifibrotic and anti-inflammatory effects. Nintenadib is also intended to slow disease progression and to reduce the risk of acute exacerbations. Check with your doctor about eligibility for these treatments.

These treatments are not a cure for the disease, but they do show a decrease in its progression.

A number of medications to treat IPF are currently being studied. The results of this research might soon lead to new therapies.

Tips and prevention

It is important to speak with your respirologist regularly to monitor your disease progression and learn about advances in research and the development of new drugs. It is also strongly recommended that patients with IPF avoid smoking, stay active by exercising according to their abilities, and adopt a diet that includes more antioxidant-rich fruits and vegetables.

Here are some tips that could improve your quality of life:

  • Quit smoking.
  • Promptly treat respiratory infections.
  • Adopt a diet rich in fruits and vegetables.
  • Get vaccinated against influenza and pneumococcus.
  • Stay active. Find out about participation in a pulmonary rehabilitation program.
  • During hot weather, heat waves, for example, think about keeping your home cool by opening the windows only at night, keeping the curtains closed, or getting an air conditioner. Moreover, a is available in some cases.


The Quebec Lung Association hosts biannual meetings for people with IPF and operates a toll-free helpline that you can call between 8 AM and 4:30 PM on Monday to Thursday and between 8 AM and noon on Friday.

Did you know

The Quebec Lung Association offers direct services to the population. For more information, visit our Patient Resources section.