00:01
So bronchitis is the first form
of lower respiratory
tract infections that we are going to discuss.
That’s a bacterial or a viral infection
of the trachea or the bronchi. It causes the
inflammation of the trachea or the bronchi,
and the consequence of that is that you cough
and also you produce phlegm, and generally
speaking, we would say that if the phlegm
is clear in color there is not a bacterial
infection, but if the phlegm is green, gunky
and thick then it’s likely to be due to
a bacterial infection. There is a wide range
of viruses and bacteria that cause this and
they are listed here. The important things
here are that actually the viruses are very
much the same as the ones that cause the common
cold, it’s just that infection has gone
further down into the respiratory tract than
just the common cold by itself. The bacteria
are the standard bacterial pathogens that
we see repeatedly during lung infections but
just infecting the lower airways but not the
alveoli in these situations. Pneumoccocus,
Haemophilus influenzae, Maraxella catarrhalis,
and then there is these atypical pathogens
Mycoplasma pneumoniae, Chlamydophila pneumoniae,
which behave in fact much more like a virus
than a normal bacterial pathogen. So the symptoms
if you have a tracheobronchitis
is that you have cough, you have phlegm production,
as a said purulent phlegm tends to suggest
a bacterial infection, and again it’s an
infection, so you get some systemic symptoms,
you have fever, you feel unwell, you go to
bed for a couple of days or so. And when you
examine the patient there aren’t many signs,
pyrexia, maybe a little bit of a tachycardia,
but there will not be much in the way of lung
signs, not unless there is an underlying lung
disease. Because tracheobronchitis itself,
because it hasn’t reached the alveoli, you
are not going to hear it when you listen to
the lungs. And again, like upper respiratory
tract infections most patients don’t need
any investigations. Occasionally if you're
worried that this might be a pneumonia, and
that is the main differential diagnosis, you
might need to do a chest X ray or blood test to
look for inflammatory markers such as C-reactive
protein. And the treatment, for most people
is actually
just to wait and let them get better. If it’s
a bacterial infection you may want to give
antibiotics. So in patients who have purulent
phlegm or are severely unwell really quite,
feeling pretty rotten, or older patients where
the risk of allowing a bacterial infection
to get hold and become a pneumonia is increased,
then you might want to give antibiotics in
those circumstances and you won’t need anything
too complex amoxicillin, clarithromycin, or
doxycycline, should be adequate to treat these
patients.
02:30
A very important consideration is that the
bacterial tracheobronchitis is a very common
cause of an exacerbation of chronic lung disease.
So this type of infection will cause the underlying
lung disease to get worse in patients who have,
for example COPD, or asthma, or bronchiectasis
and that means the patient will have increased
airways obstruction and that will precipitate
hostile remission in a significant proportion
of patients, with increased breathlessness
and potentially respiratory failure, and I
discussed the infective exacerbations of COPD
in another lecture but there is a 9% mortality
associated with these infective admissions
to hospital. So in these circumstances treatment
with antibiotics or if it’s Influenza A
infection, a neuraminidase inhibitor is probably
going to be very beneficial for the patient
and of course you need to treat the underlying
lung disease. So that’s a situation where
the infective exacerbation of the underlying
lung disease has been precipitated by a bacterial
infection of the trachea and bronchi.