When we talk about asbestos related diseases (ARD) related to Libby amphibole asbestos, we need to remember that it is a unique type of asbestos fiber that is structurally and chemically different than many other types of asbestos. Because of the unique mineralogy, diseases associated with it also present differently than the asbestos related diseases associated with the more commonly used commercial asbestos called chrysotile.

To get a complete understanding of Libby amphibole asbestos related diseases, we need to cover three topics: important medical terms, the two categories of asbestos diseases, and the difficulty of diagnosing the unique presentation of Libby amphibole asbestos disease.

Terms to Understand
Pleural Lining: A lining that surrounds the lungs that stretches and expands like a balloon when breathing
Fibrosis: scarring
Pleural Fibrosis: scarring of the pleural lining of the lungs
Pleural Plaque: a spot of scarring on the pleural lining
Pleural Thickening: when the lining around the lungs becomes thicker due to the formation scar tissue along the pleural lining
Bilateral: occurring on both sides
Diffuse: scattered throughout the lung fields
Non-calcified plaques: consist of scar tissue only
Calcified plaques: have deposits of calcium in the scar tissue
Parenchyma: the main part of an organ that contains the functioning cells. In this situation it refers to the lungs.
Interstitial: the tissue between the air sacs that are within the lungs. Thus this refers to tissue inside the lungs (also know as the interstitium)
Asbestosis: Scarring of the actual lung tissues (not the pleural tissue which is outside of the actual lung tissue).
Pneumoconiosis: Disease of the respiratory tract due to inhalation of dust particles

Two Categories of Asbestos Related Diseases

Pleural Fibrosis
The majority of people exposed to Libby amphibole asbestos who develop an asbestos related disease, develop some kind of pleural fibrosis. Based on the mineralogical features of Libby amphibole asbestos, the pleural lining is most commonly impacted by the fibers. The fibers migrate out of the lungs through tissue and/or travel in body fluids invading the pleural lining and causing disease.

It is important to remember that pleural fibrosis occurs on a continuum from localized pleural plaques to diffuse pleural thickening. All types of pleural fibrosis reduce the flexibility of the pleural lining which can limit a person's ability to breathe deeply. This restrictive disease is similar to a tight rubber band that will restrict or not allow the lungs to expand. Different people experience different severities of fibrosis and it does not always correlate with the level of asbestos exposure the person experienced. Just as the degree of fibrosis occurs on a continuum, so do the symptoms people experience. Symptoms can include shortness of breath, a chronic cough, lots of phlegm, and chest pain. Some people experience severe symptoms that greatly impact their daily life and can become a debilitating and/or terminal condition while other people may have very few symptoms. Therefore, it is very important for people to work closely with their doctor to receive ongoing medical care and evaluation.

Interstitial Disease
The second category of asbestos related disease, that is much less common in Libby but still seen in some people, is when the scarring occurs inside or on the lungs themselves. This has many names. It can be referred to as parenchymal fibrosis, interstitial disease, interstitial fibrosis, or asbestosis. The term asbestosis is mainly used in reference to scarring of the lung tissue itself. Historically, asbestosis was the common presentation of asbestos related disease, although it is noteworthy that it was typically seen with the more common commercial type of asbestos, chrysotile.

Since Libby amphibole disease frequently causes fibrosis on the outside lining around the lungs (pleural lining) rather than inside or on the actual lung tissue, the person technically has pleural fibrosis (resulting from asbestos). The person does not have asbestosis. It is also possible for people to have any range of pleural fibrosis and asbestosis at the same time.

The Difficulty of Diagnosing
Without question, the most important factor in diagnosing an asbestos related disease is obtaining a history of exposure that would be considered significant enough to cause lung disease. If a medical provider lacks this understanding, then it becomes quite easy to completely miss the diagnosis. Serious lung disease has resulted from relatively low exposure to Libby amphibole asbestos, so it would be easy to underestimate what is a significant exposure.

Further complicating the diagnosis is the subtle appearance of the pleural scarring on chest x-ray, especially in the earlier stages of disease. A chest CT scan is much more sensitive in identifying tissue scarring induced by asbestos. It is important to remember that with Libby amphibole asbestos diseases the changes are frequently on the outside lining around the lungs (the pleura lining) rather than inside the lungs. It is also a significantly more progressive disease in nature. These unique characteristics make proper diagnosis difficult for those not experienced with this particular type of asbestos disease.

It is not uncommon for Libby amphibole asbestos disease to go unrecognized or misdiagnosed by medical providers not familiar with the disease. People who are experiencing symptoms have frequently had their radiographic changes read as “shadows” or “fat” when really they are the very early changes of Libby amphibole asbestos disease. It is easy for CARD physicians to identify these changes because they read 1,000s of x-rays and CTs every year with these particular types of changes. A good analogy is related to those pictures where you are supposed to find eight animals hidden in the picture. If you know one is a lion, a hippo, a giraffe, etc; it is much easier to look for and find the animals. The same applies with radiographic changes associated with Libby amphibole asbestos diseases. Although it is important to know how to read the radiography for this particular type of disease, the most important thing is a face to face evaluation with a treating physician who can correlate clinical symptomology with diagnostic findings.