Pathophysiology of Pulmonary Fibrosis

This week we will be going over the pathophysiology of pulmonary fibrosis, which basically means that we will be talking about the structural and functional changes that your body goes through when you develop pulmonary fibrosis. This is a little bit difficult with the disease of pulmonary fibrosis though because the cause of the most common type of the disease, idiopathic pulmonary fibrosis, is still somewhat of a mystery (idiopathic meaning developing from an unknown cause). But it has been shown that triggers such as allergens, chemicals, radiation and environmental particles cause other types of pulmonary fibrosis.

            Pulmonary fibrosis is caused from scarring so when it develops your body goes through the three phases of wound healing, which are injury, inflammation, and repair. With normal wound healing your body normally brings the tissue back to its normal functioning level or at least to somewhere pretty close, but when people develop pulmonary fibrosis something goes wrong in the healing process. Normally the problem is that there is a persistent irritant that causes your body to constantly go through the wound healing process. This then causes the scar tissue to build up inside the lungs, making oxygen exchange more difficult. The factors that contribute to how bad the scarring is are the degree or level of inflammation, the angiogenesis or the formation of new blood vessels, and the amount of cellular deposits. All of these factors come together to make the perfect storm that causes bad pulmonary fibrosis to form.

           

            So far the main contributors to the mortality and morbidity of pulmonary fibrosis are unknown. It is known that it is mostly due to how you body deals with the irritants and how much scar tissue it develops in the healing process. It has also been shown that old age, smoking, cancer treatments, and occupational hazards all increase the morbidity and mortality.  Idiopathic pulmonary fibrosis is still being studied and is a big mystery to a lot of the medical world.

References:

Wilson, M., & Wynn, T. (2009, January 7). Pulmonary fibrosis: Pathogenesis, etiology and regulation. Retrieved January 25, 2015, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2675823/

Pulmonary fibrosis. (n.d.). Retrieved January 25, 2015, from http://www.mayoclinic.org/diseases-conditions/pulmonary-fibrosis/basics/risk-factors/con-20029091

Ley, B. (n.d.). Clinical Course and Prediction of Survival in Idiopathic Pulmonary Fibrosis. Retrieved January 25, 2015, from http://www.atsjournals.org/doi/full/10.1164/rccm.201006-0894CI#.VMRMbmTF8rM

Epidemiology of Pulmonary Fibrosis

In this post I will be going over the epidemiology of pulmonary fibrosis and I will be using most of my information from the article Epidemiology of Idiopathic Pulmonary Fibrosis. While this sounds like a very long and complicated word it actually has a pretty basic definition. Epidemiology is defined as the study of patterns, causes, and effects of health and disease conditions in populations. So the epidemiology of pulmonary fibrosis is about how the disease has spread and what has caused the disease to occur. The epidemiology of pulmonary fibrosis is a bit hard to track though because it is somewhat rare and there have been changes in the way it is diagnosed.

 Both the occurrence and the mortality are beginning to increase with this disease and the frequency of it is also supposed to increase in the aging population. The mortality rate is reported to be about 5 per every 100,00 persons. The potential risk factors include occupational exposures, environmental hazards, tobacco smoking, gastroesophageal reflux (GERD), and genetic factors. All of these things work together to cause scarring of the lungs which in the end makes it more difficult to breath.

Within the United States about 128,100 people are affected by pulmonary fibrosis and about 48,000 new cases are diagnosed a year. Another study showed that there are roughly 3-6 cases per 100,000 in general populations.  This disease normally occurs in middle aged to older adults (between 40 and 70 years of age) and it is slightly more common in males. There has also been no distinct pattern of geographical distribution within the United States and world wide. It has been seen equally in both rural and urban settings and there seems to be no link with any ethnicity or race. Within the United States there is a slight difference in the age-adjusted mortality. This difference is probably due to the changes in occupational and environmental exposures throughout the country. The age-adjusted mortality is lowest in the Midwest and Northeast and highest in the West and Southeast.

I hope this helped you to better understand the distribution and patterns of pulmonary fibrosis! See you next week!

References

Ley, B., & Collard, H. (2013, January 25). Epidemiology of idiopathic pulmonary fibrosis. Retrieved January 18, 2015, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3848422/

Idiopathic Pulmonary Fibrosis: Diagnosis and TreatmentInternational Consensus Statement. (n.d.). Retrieved January 18, 2015, from http://www.atsjournals.org/doi/full/10.1164/ajrccm.161.2.ats3-00#.VLtWofF8R8E

Facts About Idiopathic Pulmonary Fibrosis - Coalition For Pulmonary Fibrosis. (n.d.). Retrieved January 18, 2015, from http://www.coalitionforpf.org/facts-about-idiopathic-pulmonary-fibrosis/

Pulmonary Fibrosis 101

The lungs are one of the most important organs in the body that are sometimes overlooked by people. When someone thinks of the organs that keep him or her alive they generally go straight to the heart or the ever-important brain. But the lungs are the main organ in charge of providing your body with the life giving substance, oxygen, that every cell in your body needs. Without your lungs none of the tissue in your body would be delivered any oxygen and you would quickly die.

            The lungs are a bit of a complicated system but it is easy to break them down into something understandable. Air first enters through ones mouth or nose then makes its way down the throat and into the trachea or windpipe. At this point the trachea divides into the two bronchial tubes and then those subdivide into each lobe of the lungs. The first division of these tubes is known as the bronchioles, which then end in alveoli, where the real gas exchange happens. Alveoli are very small little air sacs that are clustered together at the end of the bronchioles like little bunches of grapes. These alveoli have tons of tiny blood vessels known as capillaries embedded in their walls. Blood passes through the capillaries and gives off carbon dioxide and takes up oxygen and those are the basics of how gas exchange happens.

There are tons of lung diseases out there that hinder ones ability to breath but I’m going to be focusing on pulmonary fibrosis. To many people this probably just sounds like an odd combination of medical terms but if you define the words separately and put them together it makes a lot of sense. Pulmonary means lungs and fibrosis means scarring so pulmonary fibrosis means scaring of the lung tissue. These scars can come from many different places including chronic inflammatory processes, infections, environmental agents, exposure to ionizing radiation, chronic conditions, certain drugs, or for unknown reasons. The scars that form in your lungs are similar to ones you can get on your skin from a cut or from a surgery but they cause much bigger problems. Scars build up on the air sacs of your lungs, known as alveoli, and eventually cause the alveoli to become stiff and make oxygen exchange to the blood very difficult. These low oxygen levels cause one to feel short of breath and have trouble with exercising. Pulmonary fibrosis also isn't really just one disease, it's actually a family of over 200 similar lung diseases!

I hope this gave you a better understanding of pulmonary fibrosis and how the lungs work. See you next week!