00:00
When we're talking about
lung infections,
we define the infection
by the site.
00:05
So that means that if you have
an infection of the pharynx,
or the nose, or the larynx,
that's called an
upper respiratory tract infection.
00:13
And that's usually the
common cold or viral infection
that we've all had
repeatedly in our lives.
00:18
There are the occasional rare
diseases caused by bacteria,
which we'll mention later
diphtheria / epiglottitis,
for example.
00:25
Then in the lower respiratory tract,
you may get infections,
which only affect the trachea,
or the bronchial tree.
00:32
Now, they tend to be that you will
get an infection of the trachea
and it will spread
to the bronchi.
00:37
They're not independent
of each other.
00:39
Usually you get a tracheobronchitis.
00:42
And again, that's often
a viral infection.
00:44
And again, we've probably all had
those several times in our lives.
00:48
That's the acute infection
of the bronchial tree.
00:51
Chronic bronchial infection
is largely a disease
called bronchiectasis.
00:55
And that's a subject I wanted to
talks on airways disease.
00:59
The main subject of this lecture
is pneumonia.
01:02
And that is an infection
that's affecting the alveoli.
01:06
And it's an acute infection.
01:09
There are a range of less
acute infections of the alveoli.
01:13
Tuberculosis being the most common.
01:15
Other things will be lung abscess,
and some very rare infections
due to fungi and unusual bacteria.
01:21
And those are mentioned
and discussed in the talk
in tuberculosis.
01:26
So today, we really concentrate
on acute pneumonia
alveolar infection,
and it could be due to a virus,
or it could be due to bacteria.
01:35
So, pneumonia is incredibly common.
01:38
It affects about one in 200 people
each year
and it is actually the commonest
cause of death in children
under the age of five
across the developing world.
01:46
As I've already mentioned,
the pneumococcus streptococcus
pneumoniae is the commonest cause.
01:53
Before we discussed pneumonia,
I'm just briefly going to cover
upper respiratory tract infections.
01:59
These are incredibly common.
02:00
As I've mentioned,
we all have had colds in our life
and will get repeated colds
as time goes by.
02:05
These are mainly due to viruses.
Rhinovirus, Adenovirus
various influenza viruses,
Metapneumovirus, etc.
02:12
And occasionally they can be
due to a bacterium
the common is been
streptococcus pyogenes,
which causes the disease,
that everyone calls strep throat.
02:19
And that's basically a bacterial
infection of the pharynx.
02:22
Patients with upper respiratory
tract infections presents similarly
an independent of what
the pathogen is
was sneezing, a sore throat,
cough, mild systemic upset,
a bit of a fever, feeling unwell,
wanting to go to bed.
02:35
And the treatment actually
is not much.
02:37
We just leave this, and people
will get better most of the time.
02:41
If you have a
strep pyogenes pharyngitis
then actually antibiotics
would be helpful,
and penicillin will be beneficial
in those circumstances.
02:50
There are a couple
of bacterial infection
the upper respiratory tract
which are very important
because they are
potentially dangerous.
02:57
Diptheria is a laryngitis.
02:59
An infection of the larynx
caused by a bacterium called
Corynebacterium diphtheriae.
03:04
The important thing
about diphtheria
is that the infection forms
what we call
a pseudomembrane.
03:09
As an extra layer of gunky tissue
on the surface of the larynx,
And that pseudomembrane
causes obstruction of the larynx.
03:18
And of course, the larynx is a
relatively small surface area,
and is where all the air that goes
into your lungs has to pass through.
03:24
And that causes
airways obstruction,
and therefore is
potentially dangerous,
and which is why
diphtheria used to be
a very common cause
of death in infants.
03:34
Epiglottitis is a rare infection
of the epiglottis,
as his name suggests,
and that's due to a bacteria
called haemophilus influenzae.
03:42
And again, it causes
swelling of the epiglottis
and therefore cause
upper airways obstruction
and is potentially dangerous
as a consequence of that.
03:49
Fortunately, diphtheria
can be vaccinated against
and has become
much less of a problem
than it used to be
in the past.
03:57
So, if we talk about lower
respiratory tract infections,
those that occur
below the larynx,
affecting the trachea,
the bronchi, or the alveoli.
04:04
In fact, most patients
lower speech transfection
will have the tracheobronchitis
that we mentioned.
04:09
That's the bottom part
of this pyramid of infection.
04:11
And only a small portion of patients
actually go on to divert
the more serious form of
lower respiratory tract infection,
which is the pneumonia.
04:19
And of those with pneumonia,
say about 100 people pneumonia,
about 70% can be treated
successfully in the community.
04:26
You don't need to get into hospital
if you have pneumonia,
because most cases
is relatively mild.
04:31
However, in some people
is a more severe disease.
04:34
And in some people
is very severe disease,
and they end up in hospital
potentially in intensive care.
04:39
And there is a mortality
which probably overall for each
100 people pneumonia,
about three will die.