In this lecture we’re going to
talk about pediatric asthma
and how we should approach
a wheezing child.
So, we see this all the time,
a child who is six years old, who comes
in to see you, who has wheezing on exam,
an expiratory, high-pitched noise.
This child may be in moderate
he might have a runny nose
or congestion or a cough.
So what is your medical diagnosis?
How do you make that
Let’s drill down on asthma.
So before we even
get started though,
I want to talk a little bit about the
difference between stridor and wheezing.
There’s a simple trick to be able to
help you make a differential diagnosis
on a patient who has wheezing
versus a patient who has stridor
and I want to make
that very clear,
Here is a child with lungs,
and two main stem bronchi.
If we were to imagine that this child
had accidentally swallowed a ball
and the ball had landed
up in the throat area
but it had not entered
the cavity of the chest,
we might imagine that when
this child breathed in
there was a negative pressure
created below this ball
and that airway space
As a result, while breathing in, this
child would make a noise, a sort of --
noise, which is from the narrowing of the
airway against the ball while breathing in.
But, while breathing out,
you can imagine that this air
would blow past the ball,
enlarging that area around the ball,
and allowing for a silent exhalation.
Patients with stridor typically
have noise on inhalation
for this very reason but
not so much in exhalation.
This would be a classic
noise for example in croup,
which is a viral inflammation
of the upper airway.
Now, of course patients can’t have
inspiratory and expiratory wheezing,
but this is classically how
we think about stridor.
Wheezing, on the other hand,
let’s now imagine this ball
was a little bit smaller
and made it all the way down to
the right main stem bronchus,
or in this case the left main stem
bronchus, it doesn’t really matter.
The point being though that now,
when this child is breathing in,
the airway is expanding and this is
because the entire lung is expanding
so the space in that airway
is actually getting bigger
and typically, the patient will not
have any noise while breathing.
However, when breathing out,
that airway is now collapsed down
and you can see that now the
airway will be pressing
up against the ball
the child will have an exhalational noise.
So wheezing is typically on exhalation
more than it is on inhalation.
Now, in a patient with asthma, you
can absolutely get inhalational
and exhalational wheezing as a result
of generally very narrowed airways,
but will typically see the
exhalational wheeze first.
So if you see a patient with
wheeze, what could be causing it?
There’s a lot more than
asthma that causes wheeze
and it’s important to
know the difference,
especially if the patient
has never wheezed before.
In the infancy period, zero to one years,
patients may very likely
Bronchiolitis is a viral
inflammation of the lung,
it does not cause smooth
muscle constriction typically,
and it’s mucus balls or it’s very small
amounts of mucus collecting in these airways
which cause a narrowed space and
absolutely present with wheezing.
If a patient is wheezing they may very
well have bronchiolitis and not asthma,
especially if they have upper respiratory
infection symptoms like congestion.
can present with wheeze,
a foreign body can absolutely present with
wheeze usually that’s in one location,
aspiration in general if a child
has oral motor dysfunction
and has a hard time swallowing,
some of that liquid might have
gotten down to their lungs,
or anatomic abnormalities of the
airway can also cause wheeze.
For instance, a CCAM or a congenital
cystic adenomatous malformation
may be pressing on that airway.
In the age one to four,
we often see virally induced
wheeze, again, bronchiolitis.
This may be a case of early asthma;
this again might be a foreign body,
especially if it’s rapidly onset,
mom found the child was normal one minute
and then next minute was wheezing;
and this might be the age at
which a child is presenting
with the pulmonary symptoms
of cystic fibrosis.
Over five years of age,
it’s probably asthma.
Patients can totally have
vocal cord dysfunction,
which might cause both stridor and wheeze.
Patients may have a
or patients may get something more complex
like allergic bronchopulmonary
which is an allergic hyperresponsiveness
to Aspergillus in the environment.
So if you see a patient with wheezing,
what are the key questions to ask?
Well, the first is at what
age did wheezing begin?
If this is the first wheeze, we’re going
to manage it a little bit differently
than if this child has been
wheezing for a long time.
Knowing the age of wheeze starting will
help you with the differential diagnosis.
You should ask whether this
wheezing is episodic or persistent.
Was it sudden onset, which
might be a foreign body,
or gradual onset, which might be asthma?
Is it associated with triggers?
Every time the child is in his
dusty grandmother’s house
he starts wheezing, that’s a
strong indicator of asthma.
Or has it responded to
albuterol in the past?
If a child has a history of wheezing
which is responsive to albuterol,
this is probably asthma.
So when you’re getting at
asthma as a diagnosis,
it’s very important to get a sense
of how severely ill is the patient
because in asthma the key
is control and prevention.
So you’ll want to ask whether
they have many events per week
or less than one
every two weeks.
You will want to ask about
night time awakenings.
Frequently, these children
will awaken with cough
and that’s a good sign of
asthma out of control.
It’s important to ask about whether this
asthma interferes with normal activity.
Can the child do sports
like the other kids?
If the child does have asthma,
it’s incredibly important to know how
often they’re getting systemic steroids.
Systemic steroids, as we’ll
talk about in a bit,
have a lot of side effects
and we want to avoid those.
Does the child have a history
of previous hospitalizations
or does the patient have previous
visits to an intensive care unit?
These are all signs of
asthma out of control.
One key historical fact is,
was this child premature.
Premature infants have a much higher risk
for asthma than non-premature infants
and that can tip you off
as to what’s going on.