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the big question with pleural fluid is
whether the patient has a transudate
or an exudate now the difference is that
the in a transudate the pleura is normal
and what you're getting is excessive
formation of pleural fluid by a passive
transfer across from the blood so this
occurs increase venous pressure such as
heart failure or a low oncotic pressure
of the blood such as decreased blood
protein content
these may be bilateral but can be
unilateral and they can be associated
peripheral edema because the same
mechanisms that cause thorough fluid in
these patients will also be caused from
peripheral edema exudates in contrast
the pleura is the abnormality the
problem is that the pleura is abnormal
and driving fluid formation and that
occurs which tumor of the pleura
information of the pleura or infection
and these tend to be unilateral and
won't have associated peripheral edema
because this is a specific pleural
abnormality so what are the causes of
pleural effusions both transit dates you
can have an increased venous pressure
and that might be due to cardiac failure
mainly right sorry cart failure but also
left-sided Carter cardiac failure could
be fluid overload
somebody's got renal failure and they
have an excess amount of fluid in the
system then you may get through pleural
fluid forming an pericardial disease
also causes pleural effusions there's
often forgotten there's a cause of these
the protein content of the blood is
required for retaining fluid within the
blood and with that with a low albumin
content you end up with with the fluid
seeping out into the pleural space into
a societies and into the peripheral
edema as well so patients were very low
protein content of the blood will
present with poor effusions these
include liver cirrhosis nephrotic
syndrome and very rarely protein losing
gut Interop fees or mayor's auction but
the commoners cause there would probably
be the renal and the liver problems
extra dates in contrast are due to
abnormalities of the pleura as I
mentioned before so these occur in
tumors and usually there's a secondary
metastases iver from a lung cancer from
a breast cancer or from a GI tract
malignancies those are common causes but
in fact multiple different types of
cancers can spread to the pleura to
cause pleural effusions and the presence
of a pleural effusion is somebody of a
no malignancy is very suggestive they're
going to have metastatic disease
affecting the pleura then again there
are a primary pleural cancers as well
actually these are very rare in general
apart from mesothelioma which is a
primary cancer of the pleura that is
associated our specialist exposure that
I've discussed in the lung long quality
lecture there are other causes of exit a
pleural effusions these are basically
involved plural information probably the
commonest cause might be a poorly
embolus where you often get smaller
fusions formed with that but then there
are connective tissue diseases
rheumatoid arthritis for example will
often have patients with pleural
effusions and systemic lupus
erythematosus is another cause of
inflammatory pleural effusions benign
asbestos effusions occur in people
who've been exposed to asbestos where
the asbestos has inflamed the pleura and
caused an exudative tore effusion but
hasn't gone on to cause a mesothelioma
occasionally drugs can cause poor
fusions the classic example being
practical and then actually many exudate
pleural effusions we cannot identify the
cause and characterizes idiopathic the
last major category of excitation or
effusions of those to to infection is an
incredibly important category and these
occur in three main circumstances one is
a perineum or confusion which is an
effusion associated with pneumonia one
is a the second is the empyema which is
a pleural infection without associated
pneumonia and the third very important
is tuberculosis
there are a whole range of very rare
causes of pleural effusions needing
qaeda for x-ray have Kyle forming in the
pleural space ovarian tumors Meek's
syndrome pancreatitis can cause
information of the pleura and of course
trauma itself can cause bleeding of
blood into the pleura and that's called
a hemothorax
but those are all in general relatively
rare or obvious diagnosis so how do you
investigate somebody with a pleural
effusion well first off you need to
confirm there's a pleural effusion by
a chest x-ray and a plural ultrasound
will be also very helpful indeed this is
an ultrasound picture showing the
clearly a very black area which is the
fluid with the lung separator from the
chest wall by that black area if
somebody has bilateral pleural effusions
then they're likely to be trans days
just because they're bilateral
so some with bilateral fusions and
obvious cause for tragedy such as known
heart failure or low album to albumin
due to nephrotic syndrome and actually
you don't need to do any further tests
the answers to why the patient has
pleural effusions is there it's due to
the the cause of the transi dates
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