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hello and welcome back
today we're going to be talking about
renal replacement therapy in our
nephrology curriculum
so before we get started i think it's
really important to look at the
prevalence of end-stage renal disease
in patients in the united states so
remember end-stage renal disease are
patients who have stage five chronic
kidney disease
and are eligible for renal replacement
therapy what i want you to notice is
that on the y-axis
we have number of patients in need of
renal replacement therapy by the
thousands
so that top line represents 800 000
whereas the x-axis
represents time starting from 1980 all
the way through 2016.
this is data taken from our usrds that's
the united states renal data systems
looking at dialysis patients and what i
want you to focus on
is that red line these are all end-stage
renal disease patients
what's interesting is that you can see
in 1980 there was maybe only
tens of thousands of patients who were
in need of renal replacement therapy
but look at what's happening now in 2016
we now have about 700 000 people that
are on renal replacement therapy
and that's either hemodialysis
represented by the yellow line
peritoneal dialysis represented by the
blue line and transplant represented by
the green line
why is this so important in addition to
causing incredible morbidity and
mortality
in these populations it's also a very
big cost to the health care system
a dialysis patient costs about 88
thousand dollars per year
a transplant patient costs about 27 000
per year
so it's a significant issue when it
comes to both the care of the patient
and the cost of the health care system
so let's talk a little bit more about
what renal replacement therapy is
it's a life-supporting therapy in
patients who have renal failure
their kidneys aren't working anymore so
we have to have something
that can do the job for them it can be
either acute or chronic
so when a patient has acute kidney
injury and they have complications from
renal failure
it would be critical to start renal
replacement therapy with hemodialysis
however if a patient has approached
chronic kidney disease
and now has transitioned to the need of
renal replacement therapy because they
have stage five chronic kidney disease
that would be chronic renal replacement
therapy
so renal replacement therapy involves
removing solute
normalization of electrolytes and
acid-base status
and removal of extracellular volume that
means salt and water
so what are the indications for doing
renal replacement therapy in our
patients
if patients develop uremic syndrome
these are symptoms and signs that result
from toxic effects of elevated levels of
nitrogenous waste
and other wastes in the blood these are
things like aliphatic amines
uremic phenols guanidines and middle
size molecules like beta2 microglobulin
one thing i want to draw your attention
to urea is not responsible for uremia
we talk about it quite a bit but we only
use it as a marker for solute removal
having a high urea level doesn't
necessarily mean that a patient is
uremic
so we talked about the symptoms of
uremia as being an indication for renal
replacement therapy what are those
that includes nausea vomiting
anorexia meaning that our patients just
aren't hungry
dysgosia that means patients have an
abnormal taste and they might describe
their food tasting metallic in quality
or like cardboard pureitis meaning that
our patients are very itchy
and having alterations in sleep they
might have insomnia at night but have
daytime hypersomnolence
and a sensation of being cold that's one
of the earliest manifestations people
feel
but they might be cold when everybody
else is hot and then finally cognitive
changes where they just can't think
correctly
some of the signs of uremia this is what
we can see on physical exam
is that patients might have a sallow
discoloration of the skin
they might have an ammonia odor to the
breath that's very distinct
and you will be able to recognize that
they could have a pericardial friction
rub
from a pericardial effusion so it's
important to do a good
cardiopulmonary exam in those patients
they might have myoclonus or seizures so
they have muscle irritability and
sometimes that actually manifests with
hiccups as well
they might have foot or wrist drop from
uremic motor neuropathy
and finally they can have prolongation
of bleeding time or from uremic platelet
dysfunction
so it's interesting because there is a
relationship between
the development of uremic syndrome and
glomerular filtration rate
so the uremic syndrome will predictably
develop when that gfr
falls below 10 mils per minute
most patients will require renal
replacement therapy once that gfr falls
between 6 and 15 ml per minute
and i do want to say that there is no
data to suggest that starting renal
replacement therapy early in patients
will portend a better outcome and in
fact with some of the
data that we do have available there's a
signal towards harm if you start
patients too early
so we really wait until a patient
absolutely needs dialysis before
starting it
and our younger healthier patients that
might be a gfr of about six mils per
minute
so when it comes to talking about
different types of renal replacement
therapy there's a few choices that we
have in our for our patients
this includes hemodialysis peritoneal
dialysis and transplant
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