00:00
So moving on to discuss
pneumonia. The hallmark,
the defining situation with pneumonia is that
you have infection of the alveoli and that
causes consolidation. So that is where the
air that’s in the alveoli has been replaced
by an inflammatory exudate, bacteria, white
blood cells, and red cells replacing the air,
and you can see that on the chest X ray. So
for example this chest X ray shows somebody
with a right upper lobe pneumonia, and there
is a white patch over the right hand of the
lung, and that reflects the dense consolidation
is that's occurring in that area, and there
is no air left in those alveoli. And this
distribution of pneumonia is a lobar pneumonia,
it's affecting one lobe only and the rest
of the lungs are clear. That’s the commonest
presentation on an acute pneumonia. You can
get pneumonia which is patchy throughout both
lungs, so little patches throughout both lungs
and that's called bronchopneumonia and this
is an example of that. This is a much more
serious disease in general because that’s
a very extensive infection and is often a
fatal event in patients with underlying severe
disease such as a cancer or another disability
such as dementia or chronic neurological deficit
of some description. A third pattern of pneumonia
that we can see
is interstitial pneumonia. Now you probably
can't tell very easily on this chest X ray
that it's abnormal but there is a widespread
reticular nodular infiltrate in both lungs,
but it’s very subtle and that represents
again a diffused pneumonia and is commonly
associated with the atypical organisms that
I mentioned earlier, Mycoplasma and Chlamydia.
01:44
The overall importance here is that, if you
have pneumonia there is some form of alveolar
consolidation, usually lobar but potentially
interstitial or bronchopneumonia as well.
01:53
Now we can detect that clinically, so if you
have somebody with pneumonia, the area of
infected lung, the area of consolidation will
be dull to percussion, and when you listen
to it they'll be crackles in that area, and
potentially bronchial breathing. And the chest
X ray as we’ve seen is obviously abnormal.
It shows airspace shadowing with white patches
in the infected area, and occasionally what
we call air bronchograms. That’s where the
bronchus that’s moving through the consolidated
lung has been delineated by the alveolar consolidation
I've stated here. So it shows up as a black
tube going through a consolidated area.