Environmental

Pulmonary fibrosis (PF) is part of a larger group of more than 200 interstitial lung diseases (also known as ILDs) that are characterized by inflammation and/or scarring in the lung. In ILDs, the injury and damage occurs in the walls of the air sacs of the lung, as well as in the tissue and space around these air sacs. When an interstitial lung disease includes scar tissue in the lung, we call it pulmonary fibrosis.

One of the subgroups of interstitial lung disease is those that are related to environmental exposures, referred to as “hypersensitivity pneumonitis. ” Hypersensitivity pneumonitis (HP) results from the lungs’ reaction to inhaled organic particles or “antigens”.  This reaction can involve inflammation or scarring (also known as fibrosis), or a combination of both.

• This type of lung injury can be acute, in which case the problem is usually more inflammatory and can be reversible with avoidance of the exposure causing the disease.
• HP can also have a more subtle onset, “subacute” or “chronic” form, which can have a less dramatic presentation. In these cases, there is more fibrosis or scarring injury to the lungs, which is not fully reversible.

When a doctor or other healthcare provider suspects that a patient has ILD, they will collect information about the patient’s medical and personal history, work and home environment, hobbies, and illness that may be present in the family. This can help a doctor identify exposures or other diseases that might have caused lung injury and scarring. The doctor will also often order pulmonary function tests, a chest x-ray, blood work, and a high-resolution CT scan.

Pulmonary function tests measure how much air the lungs can hold, and how the lungs are working overall. Scarring can cause the lungs to shrink, and it can also make them stiff and unable to fully expand. This means the lungs are able to hold less air. Scar tissue may also affect the ability of the lungs to transfer oxygen to the bloodstream.

Blood work (serology) can provide information about exposures that may have caused a person’s lung injury, or show that other diseases are present which may be associated with the development of PF. 

A high-resolution computed tomography (HRCT) scan is a special type of x-ray that shows fine detail of the lung tissue. On a CT scan (also known as CAT scan) healthy lung tissue looks nearly black, and scar tissue and inflammation appear grey or white.

When a doctor or other healthcare provider suspects that a patient has HP, they will discuss with you potential “antigen” (inhaled particle) exposures in the environments that you frequently visit. Unfortunately, even with a complete history, not all patients can identify the trigger for their disease. In some cases, a bronchoscopy or lung biopsy may be performed to aid in diagnosis but cannot typically help to identify a specific exposure.