At first, we will take a look
at the upper portion and this is your tracheas,
it's cartilaginous. And it has mucociliary clearance
which means that it is made up of columnar.
Let me give you another example. Say that
you are smoking, and if you are smoking
then what has to happen. Well, the trachea
and company have to protect themselves, don’t
they? And how do you protect yourself against
smoke? Not with columnar cells. It's
squamous cells. So, if the columnar cell
has to turn into squamous cell, what do you
call this? Good. Metaplasia. You see the point
here. As we move forward and we go deeper
beyond the bronchi into the bronchiole,
then we get into goblet cells and it will produce
quite a bit of mucous. And what does mucous
mean to you? For example, let's say that you
have three month of productive cough for two
consecutive years. That is the definition
of what? Chronic bronchitis. So at this point,
as we move forward, the terminology becomes
very important. It is important that you remain
alert at all the times so that you understand
my language and my terminology so that you
know as to what I am referring to, kind of
like what I have been doing in my entire course.
Okay, now, what’s beautiful about this is
the fact that well, take a look at your right
first. Proximal portion of the pulmonary
tree. There is my trachea, and there is your
bronchi. Now, we are going to put in some
pathologies. We said that as far as the upper
structure is concerned that it is made up
of cartilage. Has to be, because you want
that to be supported. You want that to strictly
conduct air without any interference and down
into alveoli. So why would you ever want
premature collapse? You don’t. You need
those cartilaginous rings. Now, what you are
seeing here in blue will be the infections
and what you are seeing here in red will be
the diseases. Let's take a look at the parainfluenza
You have heard of laryngotracheal bronchitis.
Now, close your eyes and think of this anatomically
in terms of sequence. What’s the first structure?
Larynx. What is the next structure, distal?
trachea. What’s after that? Bronchi. There
you have it. So, instead of memorizing this,
while you should already know from anatomy,
the sequence. And so what am I referring to?
What is this? It is parainfluenza. This is
going to be your croup, isn’t it? So, your
croup has your type of cough to it, but here,
because how proximal it is. Now, if you know
what a steeple is on top of a building such
as a church then it is going to be that area
of the building or the roof where it comes
together like a steeple. Well, in parainfluenza
or your croup, one of the most common causes
of croup is parainfluenza. So, if you want
C-R-O-U-P-P-P, often times the “P” is silent,
but anyhow. Point is, it is a steeple sign
that you might find on x-ray where, look where
you are, up in the proximal portion.
And we have another infection number 5 and
well take a look at this, located blue, circle
5 and that’s your bronchopneumonia.
Allow the name to speak to you. “Broncho”
meaning to say that you have involvement of
the bronchi. So, we will see this later on
as well as we get into distal segments, but
giving you an understanding that this is involving
the bronchi. A common organism here would
be Klebsiella pneumonia. When you think about
Klebsiella pneumonia, you should be thinking
about perhaps this, you mean, if you have
fun with it a little bit. Elderly patient
and maybe perhaps a nursing home and they
are hiding a bottle of alcohol. And every
so often, they take to the canter and take
a swig. And so, therefore, the most common
pneumonia that you might find
in elderly/perhaps alcoholics, kind of put
them together there, if that helps you, would
be the organism Klebsiella pneumonia. In microbiology,
you have gone through different pneumonias
and what they look like. For example, staph
aureus, would be, well, what's aureo,
what’s AU mean to you on the periodic table?
Gold, isn’t it? So therefore, the type
of phlegm or the productive cough that you
have would be yellow, goldish clear. Say that
it's something like pseudomonas. Well, that begins
with a “P”. There is a little microbiologic
agent called pyocyanine. What color is your
sputum there? Green. Often times, pseudomonas
as well, rarely, but still could result in
your nails becoming green. Pyocyanine is an
interesting component of Pseudomonas.
Those would be infections, diseases.
What are squamous cell carcinoma or small
cell? Now, the reason that I have put both
of these together is because when we get into
x-ray, we talk about lung cancers. While these
cancers will be located centrally, and by that
I mean it will be located by the mediastinum.
Is that understood? Now squamous, normally
speaking, if you remember the trachea and
the bronchi, then as you said earlier, you will
undergo the process of what physiologic adaptation?
Good, it is called metaplasia. Let me ask
you something. What if you are smoking and
your patient unfortunately develops progressive
dysphagia? What's dysphagia mean? Difficulty
with swallowing. That would be in esophagus.
Be careful. Now, smoking obviously could result
in cancers up and down the body, but I have
given you two here. One would be in the trachea,
and this would be something like, maybe squamous
cell and that is a metaplastic transformation.
But, what if you were in the esophagus? Is
that a metaplastic transformation before you
went into cancer, before you went into dysplasia
and then cancer? No, it wasn’t. Is that
clear? Really? Because esophagus made
up of what kind of histology, normally? Think.
Non-keratinized type of, you tell me.
Good, squamous. So, it began as squamous.
Your smoking ended up as squamous cancer.
So, the process never went through a metaplastic
change before going to dysplasia and cancer.
Is that clear? But, Dr Raj, I thought that
you had Barrett’s esophagus? Yes, Barrett’s
esophagus is due to why? Oh, reflux of acid.
Okay, so, what we wished to do here as we
go through with this is make sure that you
are clear about definitions, common things
that you'll encounter on your board exams and
things that you want to look out for over
and over and over again.
We are strictly in the trachea. Now, small
cell, extremely aggressive, another name
for small cell, you should know is Oat cell.
Which you notice isn’t here is adenocarcinoma,
which is the most common lung cancer. All
these three will group together later and
it is called bronchogenic.
Now, you take a look at number 3. Number 3
is chronic bronchitis. Where are you?
Bronchi. Proximal portion. What's happening.
You might have heard of something like a Reid
index. If you have, it will make perfect sense
to you. Chronic bronchitis, inflammation of
the bronchi, that is taking place you are
producing quite a bit of mucous, usually due
to smoking. And the way they will approach
obstructive diseases in the
lung will be rather novel for you and it will
be much simpler and it's current day practice
that you have to be familiar with
because chronic bronchitis, emphysema and
asthma and I will show this as we go through
with this, has overlapping type of
signs and symptoms, as you shall see. You
will have fun with this and the definition
of chronic bronchitis is three
months of consecutive productive
cough over two consecutive years. You must
have a span of three months in which your
patient is coughing for three consecutive months,
keep that in mind, because
you will be given something like that at some
point in time in terms of history on your
clinical rotations, on exams and so forth.