Acute Renal Failure (ARF) with complete solutions

Acute
Renal
Failure
(ARF)
What
is
acute
renal
failure?
-
ANSWER--an
abrupt
decrease
in
renal
function
resulting
in
retention
of
nitrogenous
waste
-result
of
decreased
renal
blood
flow,
intrinsic
renal
parenchymal
diseases,
or
obstruction
of
urine
flow
-acute
tubular
necrosis
is
the
most
common
intrinsic
cause
of
ARF
What
is
the
most
common
intrinsic
cause
of
ARF?
-
ANSWER-acute
tubular
necrosis
What
is
the
epidemiology
of
ARF?
-
ANSWER-1%
on
admission
to
hospital
2-5%
during
hospitalization
What
is
the
etiology
of
ARF
in
the
hospitalized
patient?
-
ANSWER-In
hospitalized
adults,
the
most
common
cause
of
ARF
is
prerenal
azotemia--30-60%
of
all
cases
In
hospitalized
adults,
1-10%
of
ARF
is
associated
with
postrenal
azotemia
Acute
tubular
necrosis
(ATN)
is
most
common
intrinsic
renal
disease
leading
to
ARF
**common
predisposing
factor
is
prerenal
azotemia
**40-60%
in
post
trauma
or
postoperative
patient
What
is
the
most
common
intrinsic
renal
disease
that
leads
to
ARF?
-
ANSWER-acute
tubular
necrosis
In
hospitalized
adults,
the
most
common
cause
of
ARF
is
what?
-
ANSWER-prerenal
azotemia
30-60%
What
is
the
pathophysiology
of
prerenal
azotemia?
-
ANSWER-reduction
in
glomerular
perfusion
secondary
to
decreased
volume
or
situations
with
decreased
circulation
(CHF,
advanced
cirrhosis,
and
septic
states)--high
(>20)
ratio
of
BUN
to
serum
creatinine
ratio
with
low
urine
output
**
they
look
warm,
flushed,
and
sepsis
is
common
(similar
to
tylenol
OD) What
is
the
pathophysiology
of
acute
tubular
necrosis
(ATN)?
-
ANSWER-decreased
blood
flow
with
ischemia
What
is
the
clinical
presentation
of
ARF?
-
ANSWER-Decrease
in
urine
output,
dark
urine,
cola-colored
urine,
and
sx
suggestive
of
uremia,
such
as
fatigue,
weakness,
N/V
loss
of
appetite,
metallic
taste
in
the
mouth,
itching,
confusion,
fluid
retention,
and
HTN
What
is
the
chart
review,
hx,
and
px
of
ARF?
-
ANSWER--correct
diagnosis
depend
on
careful
review
of
patient
data
and
hx
-start
with
hx
and
review
of
chart
(look
for
reduced
weight,
postural
BP
and
pulse
changes,
and
also
a
reduced
JVP)
-examine
abdomen
for
distention
of
the
bladder
What
labs
would
you
look
at
for
ARF?
-
ANSWER-ratio
of
BUN
to
creatinine
urinary
volume
UA
and
urine
sediment
distinguish
btwn
prerenal
azotemia
and
acute
tubular
necrosis
What
would
the
ratio
of
BUN
to
creatinine
show
in
ARF?
-
ANSWER--in
prerenal
azotemia,
BUN/creatinine
ratio
is
>
20:1
-a
high
level
of
creatinine
that
exceeds
the
elevation
of
BUN
suggests
rhabdomyolysis
-within
48
hours
if
the
serum
creatinine
rises
at
least
0.3
mg/dl
(suspect)
What
are
other
causes
of
an
increased
BUN/creatinine
ratio?
-
ANSWER-GI
bleeding,
use
of
systemic
steroids;
catabolism
caused
by
medical
problems,
or
a
high
protein
diet
What
would
the
urinary
volume
show
in
ARF?
-
ANSWER-less
than
400
ml/day
with
oliguria
<
100
ml/day
with
anuria
What
would
the
UA
and
urine
sediment
show
in
ARF?
-
ANSWER--in
prerenal
failure:
moderate
number
of
hyaline
and
finely
granular
casts
may
be
seen