00:02
In this lecture, we’re going
to discuss pulmonary diseases
that show up in older children.
00:07
Now, we’re going to exclude cystic
fibrosis, which has its own lecture,
and we’re excluding pulmonary
diseases that show up in infants,
which also has its own lecture.
00:18
This is really other problems in children.
00:22
Let’s start off with
pulmonary embolism.
00:26
So a pulmonary embolism can happen, but
it’s very in children compared to adults.
00:34
It is seen more commonly in
diseases or circumstances
where there’s a predisposition
to forming a clot
and the mortality rate is
only 20% that of adults.
00:48
In other words, children are more likely
to have smaller pulmonary embolisms
and they’re more likely to survive
the event and live past it.
00:59
So in order to understand the
pathophysiology of the pulmonary embolism,
we have to recall
Virchow’s Triad,
the three things that are
resulting in a clot inside a blood vessel.
01:11
One is stasis,
one is the
hypercoagulable state,
and the other is
endothelial damage.
01:18
And we have these three things,
we’re at increased risk for creating
a thrombus inside the child.
01:25
That thrombus can then proceed
up and into the lungs,
where it causes the
pulmonary embolism.
01:32
One way to remember
it is I's and O's.
01:35
So there are Is and Os that are responsible
for causing pulmonary embolism.
01:40
The I's are indwelling
central lines,
prolonged immobilization,
or inherited disorders
of coagulation.
01:50
Remember, in kids,
they present with unusual congenital
problems more often than adults do,
so these inherited disorders are
something we will absolutely think of
in a child who presents
with a pulmonary embolism.
02:05
The O's: obesity, oral contraceptive
pills, or orthopedic surgery,
which is really more of the immobilization,
but a nice way to remember that.
02:17
So in terms of the
pathology of the disease,
most pulmonary embolisms start as a thrombus
in a vein, and then fly into the lungs.
02:27
This is usually starting
off in a lower extremity
but can be in the upper extremity,
the pelvis, the kidney,
or even just the right
side of the heart.
02:36
And as we say it before, these are rare,
but even rarer still are air emboli,
tumor emboli, or fat emboli,
which can cause similar symptoms,
but aren’t necessarily from a clot.
02:50
So the pulmonary embolus, if
it’s rare, how do we suspect it?
These patients will typically have a history
of sudden onset pleuritic chest pain.
03:03
They’ll have difficulty of
breathing that is sudden onset.
03:07
About 50% of them
will have a cough
and about a third of them
will have hemoptysis.
03:12
Hemoptysis in a child
is never normal.
03:17
If they’re presenting with a
massive pulmonary embolism,
which is exceptionally rare and
much rarer than in adults,
these patients will have a sudden onset
cyanosis and right ventricular failure.
03:31
These are the patients with
jugular venous distention,
hepatomegaly, they may have a single
loud S2, other problems like that.
03:43
The majority of children presenting
with a pulmonary embolism
though are going to
be non-massive PEs.
03:49
About half of these children
will have tachypnea,
they will often
have tachycardia,
and you may auscultate.
03:56
While you’re examining them, you
may hear crackles, wheezing,
or usually they’re just
clear to auscultation.
04:05
So as you can see, a lot of these
symptoms are somewhat nonspecific
and in children it’s
a rare condition,
so you can imagine this is a challenging
diagnosis to make, and it is.
04:17
One test that’s particularly helpful and
important to know about is the D-dimer.
04:22
This is very important.
04:24
A positive D-dimer does not
confirm a pulmonary embolism.
04:30
The D-dimer is an acute phase reactant
that can be elevated by almost anything.
04:36
However, it’s almost unheard of to have a
pulmonary embolism have a normal D-dimer.
04:43
So we routinely get the D-dimer as a
way of ruling out pulmonary embolism.
04:48
If I have a patient with
chest pain and tachypnea
and I’m thinking maybe
it’s a pulmonary embolism
because the girl takes
oral contraceptive pills,
but I get a normal D-dimer, I usually
won’t pursue this any further.
05:03
Other testing that’s
important can be an ABG,
which may show V/Q mismatch in the
lung as a result of that clot.
05:11
A chest x-ray may show
an area of collapse.
05:15
But, really, the most important
test for truly ruling out
a pulmonary embolism is the spiral CT.
05:22
Now, we do like to avoid
radiation in children.
05:26
Remember, children are probably
at more risk for cancer
as a result of radiation exposure simply
because there’s more mitosis going on
and more opportunity for
negatively impacting mitosis.
05:39
But the spiral CT
is the way to go.
05:42
In the books, there will
be mentions of V/Q scans;
however, their accuracy at
predicting pulmonary embolism
is really no better
than the spiral CT.
05:54
Also, you may read about angiography as the
gold standard and this is absolutely true.
06:00
It is the gold standard,
but really is very seldom used.
06:04
The reason being
spiral CT is very good
and angiography confers actually
quite a bit of radiation.