Emphysema: Introduction

by Carlo Raj, MD

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    00:01 Now that we’ve looked at the overview, of obstructive lung disease and the different overlaps of asthma, chronic bronchitis and emphysema, we dive into the particulars of emphysema. Now, what you must focus upon would be the definition that we are seeing here and the fact that it does technically come under COPD, which if you were to take a look at those overlapping diagnosis of circles that I showed you, then this would be the green shaded area.

    00:29 So, what is emphysema? Defined by abnormal, permanent enlargement of the airspace in distal to the terminal bronchioles. So, where are you? You’re getting closer to your alveoli. You’re thinking about your alveolar ducts and you’re thinking about the alveoli.

    00:48 That is accompanied by destruction of the airspace walls without obvious fibrosis and that’s a big point. Because if fibrosis was to take place then you wouldn’t be referring to obstructive lung disease, would you? No. You would then be referring to restrictive lung disease.

    01:05 Now, before we move on, think about the anatomy of your respiratory tree. Distal to the terminal bronchioles, you are thinking about the respiratory bronchioles, you are thinking about the alveolar duct and alveoli and those structures are supported by parenchyma.

    01:21 There are septae that are involved, keep that in mind, as we go through various steps of emphysema and there will be a little bit of a difference between the damage that’s taking place to the ducts versus the damage that will be taking place permanently to the alveoli.

    01:35 Let us begin.

    01:37 So, to begin with, I want you to take a look at the cartoon and where we are. On the very left, move down the divisions and generations of your trachea through the bronchi, through the bronchiole, eventually through the terminal bronchioles of entry into the respiratory and, on or in the middle you have your normal bronchiole and alveoli. The reason you can say that is because the septae there are dividing each alveoli, kind of looks like, well, a cluster of grapes, doesn’t it? Whereas if there is emphysema, just as a theme here, it’s a fact that there is a destruction that’s taking place of the parenchyma. So, you can only imagine here that you are losing your surface area. If you lose your surface area, this means that you do not have effective gas exchange. And hence, your DLCO, your diffusion capacity of carbon monoxide, in fact, is decreased. It’s not because of decreased compliance, in fact, in emphysema, what happens to your compliance, do you remember? It increases, but it doesn’t mean that your lungs are more effective as being a breathing apparatus, it’s a fact that now you lost your surface area. Now, this is in general.

    02:50 Obviously, there’s a lot more detail to go into.

    About the Lecture

    The lecture Emphysema: Introduction by Carlo Raj, MD is from the course Obstructive Lung Disease.

    Included Quiz Questions

    1. Permanent dilatation of airspace distal to terminal bronchioles.
    2. Temporary dilatation of the airspaces distal to terminal bronchioles
    3. Permanent dilatation of the airspaces proximal to terminal bronchioles
    4. Permanent dilatation of airspaces distal to the bronchi
    5. Temporary dilatation of the airspaces proximal to terminal bronchioles
    1. The decreased surface area caused by alveolar septal destruction leads to lesser diffusion of gases
    2. There is decreased compliance allowing lesser diffusion of gases
    3. There is increased obstruction which allows lesser diffusion of gases
    4. There is decreased air entry and air exit which allows lesser diffusion of gases
    5. There is increased fibrosis which causes decreased diffusion of gases
    1. Emphysema is characterized by abnormal and permanent dilation of the airspace distal to the terminal bronchiole.
    2. The primary feature of emphysema is fibrosis.
    3. Airspace walls are usually not affected in emphysema.
    4. Emphysema is characterized by a reversible dilation of the airspace.
    5. Emphysema has no impact on DLCO.

    Author of lecture Emphysema: Introduction

     Carlo Raj, MD

    Carlo Raj, MD

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