Well, let’s talk about edema that develops
not because of an abnormality in the lymphatic
vessels but because of another disease.
There are two very common diseases that lead
to edema, particularly in the legs. And sometimes
it can spread all the way up into the lower
abdomen. One of these is heart failure and
the other is liver failure. Let’s talk a
little bit about heart failure.
What happens in heart failure is that the
heart doesn’t contract adequately, particularly
the left ventricle. When it doesn’t contract
adequately, there’s all kinds of remodelling,
changes. The ventricle dilates in an attempt
to keep up the cardiac output. And when it
does that, the pressures during diastole – that
is during the resting phase – rise and are
transmitted back to the lung and, eventually,
are transmitted back to the venous system
and venous pressure rises.
When venous pressure rises, then capillary
pressure rises. And now you have a marked
difference between the hydrostatic and the
oncotic pressure and fluid leaks out at a
much faster rate into the tissues. At a rate
so fast that the lymphatics cannot drain it
adequately. And what you end up with is swelling
– or edema, which is the medical term – particularly
in the lower extremities.
Persistent edema is often a sign of heart
failure. It can also be a sign, on the other
hand, of liver failure. What happens in liver
failure is that the liver fails to produce
albumin and other proteins to maintain oncotic
pressure. So down in the capillaries instead
of increased hydrostatic pressure, you have
decreased oncotic pressure. And, again, excess
fluid leaks out of the capillaries and into
Both of these forms of edema can be very
difficult and challenging to remove although
most patients with mild liver failure or mild
heart failure will respond to diuretics – that
is medicines that increase the flow of urinary
fluid and increase the amount of urine that
one makes and therefore gets rid of this extra
fluid that’s in the body.
So, for heart failure, we have a whole variety
of other drugs. We’re not going to review
them right now. Those of you who are interested,
it’s in the Cardiology series. There’s
a whole lecture on heart failure. It discusses
all of the various drugs, particularly a drug
called beta blockers which decrease the heart
rate and allow the heart to heal to some degree
from whatever injury it’s had. And, of course,
diuretics increase the urine flow and get
the fluid out.
In liver failure, we also use diuretics. But
in particular there’s a diuretic called
spironolactone that blocks aldosterone. Remember
the renin-angiotensin-aldosterone system?
Well, this spironolactone drug blocks the
aldosterone and allows the kidneys to get
rid of more fluid.
Often edema in liver failure is much more
challenging to get rid of than in heart failure
and often will collect in the abdomen. The
patients will have a belly full of fluid at
the end stage of liver failure. It’s a little
easier to control the edema in heart failure.
Well let’s talk about conditions where the
lymphatics are destroyed by disease or surgery.
The commonest one – although much less common
these days – is when a female patient with
breast cancer gets a radical mastectomy in
which all the lymph nodes and the upper thoracic
lymph nodes are removed to make sure that
there’s no cancer cells that survive. What
you do then is you cause a marked decrease
in the lymphatic ability to drain the arm
and, very often, these women have chronic
It’s often managed as I’ll mention in
a moment. Sometimes you can put a pump on
that squeezes the lymphatic fluid out of the
arm. And compressive or elastic bandages will
There are a number of parasitic diseases that
actually destroy the lymph vessels and, of
course, then the fluid doesn’t drain out
of the tissues. And you actually see a picture
here of a woman who has had a parasitic disease
that destroyed her lymphatic vessels. And
you can see her massive peripheral edema
in her legs.
The massive edema that occurs is called elephantiasis
because it looks like the bulky leg of an
The commonest parasite that does this is in
Africa. It’s Wuchereria bancrofti. This
little worm is introduced through the skin
usually by insect bites. And it then works
its way into the lymphatic vessels and the
lymphatic vessels develop fibrosis and scarring
and close down. And that leads to elephantiasis.
There’s a genetic disease where people are
born without good lymph vessels. That’s
known as the Proteus syndrome. It’s very
rare but again you get the same thing: elephantiasis
because the tissue fluid never can leave the
limb or leaves very, very poorly.
And occasionally there will be an autoimmune
disease which will attack the lymph vessels
and result in their scarring and fibrosis
and could also lead to elephantiasis – to
There’s a huge problem there. This amount
of edema impairs tissue nutrition because
the blood flow has a hard time getting in
because of the massive edema. And often you
can develop ulcers and even necrosis – death
of tissue. And sometimes even amputation is
So the therapy for all of these forms of edema
consists of diuresis – that is you increase
urine flow in an attempt to get the fluid
out of the body.
If you raise the limb, that will help some
of it with gravity to drain the fluid out.
And then, as I mentioned, compression stockings
or arm binding. And there are intermittent
compression devices that can be bought. Particularly
women who’ve had a radical mastectomy often
two or three times a day will put their arm
in the compression device and it squeezes
the lymph fluid out of the arm so that there’s
not so much edema in the arm.