Pulmonary Fibrosis

Pulmonary Fibrosis is classified as a Restrictive lung disease and primarily affects the structure of the lung. It is characterized by an increased stiffness of the lung and a loss of functional alveolar surface area. The increased stiffness acts to reduce lung capacity. The decrease in alveolar surface area reduces the ability of the lungs to transfer oxygen and carbon dioxide.

Pulmonary Fibrosis status is best monitored by FVC, DLCO and Oximetry.

A typical PFT pattern for Pulmonary Fibrosis:

Spirometry FVC Reduced
  FEV1 Normal or reduced
  FEV1/FVC Ratio Normal or Elevated
Lung Volumes TLC Reduced
  RV Reduced
Diffusing Capacity DLCO Reduced
Oximetry SpO2 Reduced

The severity of Pulmonary Fibrosis is determined by the decrease in TLC:

TLC >=60% and <80% of predicted Mild restriction
TLC >=40% and <60% of predicted Moderate restriction
TLC <40% of predicted Severe restriction


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PFT Patient by Richard Johnston is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

7 thoughts on “Pulmonary Fibrosis”

  1. I would like to add a few more details about the diaesse. You begin to notice something is wrong only when you constantly suffer from shortness of breath. Another one of its symptom is expanded chest and the patient also looses weight. It is a chronic obstructive pulmonary diaesse. It causes the destruction of lung tissues around alveoli .one of the main cause of it is smoking tobacco and somepeople suffer from it during old age due to deterioration of lungs.[]

    1. Claudia –

      You are mis-informed. Pulmonary fibrosis is most definitely not an obstructive disease like COPD, it is restrictive. The chest does not expand (you’re thinking of a barrel chest that used to be relatively common with untreated emphysema). There is an association with smoking, but no causative link has been proved. Weight loss is commonly associated with any lung disease that causes extreme shortness of breath and is seen in both COPD and IPF.

      – Richard

        1. Donna –

          Mild covers a fairly wide swath and actually includes spirometry that is within normal limits. So, mild IPF (most often diagnosed by CT scan) can be something like this: FVC 85% of predicted, FEV1 90% of predicted, FEV1/FVC ratio 105% of predicted. Or it could be something like this: FVC 70% of predicted, FEV1 70% of predicted, FEV1/FVC ratio 100% of predicted. The severity of IPF usually comes from the TLC percent of predicted (i.e. less than 80% of predicted) but I’ve seen individuals whose IPF was considered severe because their DLCO was less than 40% of predicted even though their TLC was greater than 80% of predicted.

          Regards, Richard

    2. You are correct, Richard. Thank you. It’s more likely associated with GERD and damage it causes to lungs at some point just as one theory. Also autoimmune caused or from certain chemo drugs. COPD is the one mainly caused by smoking.

      1. Shawna –

        Interestingly there is also a connection between smoking and IPF. I believe that more than one study has showed that over 90% of individuals with IPF were former smokers. Another reason not to smoke!

        – Richard

  2. I lost my husband to IPF Jan ’16, he suffered with this disease for 2 yrs, he never smoked but was surrounded by second hand smoke practically all his life, hopefully they will find a cause and a cure, for this in the not so distant future

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