Okay. So where we are here
with our flow volume spirometry is well, just
a recap, in the middle is normal. Bottom
loop represents inspiration. I want you
to begin at residual volume, you should always
have a little bit of volume in your lung.
The bottom half represents inspiration.
What does it mean when you get to the top,
where you have maximum volume in your lung?
That’s called TLC. Okay, obviously the top
half we spend time with, that’s your exhalation.
Take a look at the right, that’s my pathology
in restrictive, isn’t it? Which one? You
tell me. The red looks normal, that loop is
now shifted to the right, that’s the pathology.
So, take a look at your exhalation do you
see a scalloped pattern? Nope. What about
the peak flow? Diminished and it’s moved
to the right, so tell me about the total lung
capacity of the normal which is the red at
6 compared to total lung capacity of the restrictive
lung at approximately 3. Obviously
decreased, right? Tell me about the FVC.
It is decreased. What about FEV1/FVC ratio?
Never decreased, either normal or elevated.
In current day practice with restrictive lung
disease here’s the algorithm that you want
to be quite familiar with. Now, to begin with
a couple of abbreviations that you’ll come
across quite commonly and the names that you
want to be able to interchange readily at
a given time. We have diffused parenchymal,
a.k.a interstitial lung disease abbreviated
accordingly. With DPLD or diffused parenchymal
lung disease, interstitial. Known causes maybe
drugs. What drugs that we talked about already?
Those drugs included things like bleomycin,
busulfan and company. Known causes include
maybe perhaps rheumatoid arthritis.
Do not forget that, that’s a big one for
us, you’ll see later.
Next, what else are we going to do? Well,
we take a look at something called Idiopathic
or now better yet called another type known as
interstitial pneumonia and we’ll take this category ladies
and gentlemen and we’re going to dissect
the heck out of it, you’ll see. Before we
get there though, let’s take a look at few
others. Granulomatous, so what does that
mean to you? Think of sarcoidosis huh?
Sarcoidosis type of diffused parenchyma would
be non-caseating granuloma. So, create yourself
this type of flowchart, algorithm in your
head so that you’re able to perfectly place
yourself accordingly, we need to in terms
of differentials. Other forms, well something
like lymphangioleiomyomatosis, you have Langerhans
cell type of issues and eosinophilic type
of pneumonia. Okay now with eosinophilic pneumonia
you’ll find that discussion to be quite
interesting. For example you’ve heard of
Next, well we will going ahead and take this
IIP which is idiopathic interstitial type
of pneumonia, and then we will further divide
this. The non-familial type is the most common
where 80% of your patients will then
be presenting as non-familial.
With non-familial we would then break this
into, chronic fibrosing, acute fibrosing and
Let’s take a look. If it’s chronic fibrosing,
it’s idiopathic pulmonary fibrosis, this
is the one that you have seen quite often
in your medical education but truly ladies
and gentlemen I beg of you to at least give
yourself an organization pattern when dealing
with diffused parenchymal type of restrictive
lung disease. Chronic fibrosing. If it’s
the gene associated with it that’s now been
found, it’s mucous, think of it that way.
So you have MUC and then I don’t know how
to do this but you have to memorize, 5B. Okay,
I can only take you so far. Next, what if
it’s acute type? Well, we have something
here called cryptogenic organizing type of
pneumonia and also we have acute interstitial
pneumonia. Cryptogenic becomes important to
us. I'll have a few words for you as we go
through that differential. And smoking related.
If it’s smoking related respiratory bronchiolitis,
interstitial lung disease and something called
desquamating interstitial pneumonia. Now,
in these I have then bolded common conditions
that then you should know as far as your everyday
practice and obviously on your
boards of any type.
Continue. Okay, so interstitial lung disease
well for the most part a term falling out
of favour for diffuse lung disease which is
good. The entire lung is being affected mostly
in the interstitium though. Wide variety of
causes, we’ve walked through a bunch of
differentials. Generally all are characterized
by parenchymal, hence
in the previous flowchart we looked at diffuse
parenchymal lung disease as being the common
theme. Now, this type of parenchymal lung
disease involvement seen on radiology or in
pathology and this of course give you the
restriction type of pulmonary function test.
Separate airway disease obviously from obstructive.
Not all diffused lung disease produce restrictive
physiology so keep that in mind.