ACUTE KIDNEY INJURY
4-34
Table 4-11: Category
FENa
Causes
Volume depletion
Prerenal
Acute K1dney Injury Labs and Clues
FEuricacid
<1%
<12%
FE urea
<35%
Decreased
Uosm >400
Urine
Urine
Na+
Sediment
Suspect
<20
in Patient with
...
Bleeding
mOsm/L
CHF
EABV *
Cirrhosis!hepatorenal
NSAIDs
Abdominal compartment
ACEI
syndrome (ACS) Nephrotic syndrome GI fluid loss (nausea! vomiting/diarrhea)
Intrinsic
Diseases of,
ATN*>2%
renal
or damage to,
GN*<l%
>20%
>50%
>20
300-350 mOsm/L
Red cell casts
Infections
and/or protein
SLE
the glomeruli,
(GN)
Vasculitis
tubules, or
Dirty brown
Drugs (aminoglycosides,
casts (ATN*)
amphotericin, cisplatin,
Eos (AIN*)
NSAIDs)
interstitium
Contrasts/IV dyes Atheroembolism Heroin Myeloma Diabetes H TN Hypotension, shock Postrenal
Varies
Varies
Varies
Obstruction
Normal
Elderly males Colicky pain
Level indicating prerenal
Fractional excretion**
Changed by diuretics
*EABV
AKJ
ATN
•
FEurea
<35
No
FEuricacid
<12
No
•
=
AIN
effective arterial blood volume
acute tubular necrosis
glomerulonephritis
=
acute interstitial nephritis
**Recent diuretics use can alter the FENa and, in this setting, FEurea and FEuric acid are more reliable.
dysfunction. ACS can occur with abdominal trauma, mas
No evidence of parenchymal kidney disease (normal U/A, proteinuria<
GN
Yes
<1
=
=
500 mg/d, normal renal
sive ascites, intraperitoneal bleeding, acute pancreatitis,
ultrasound)
and any other condition that raises the intraabdominal
Absence of any other apparent cause of AKI,
pressures. AKI in ACS most likely occurs secondary to
including shock, nephrotoxins, and infection
renal vein compression, which increases venous resis
(except peritonitis)
tance and impairs venous drainage.
Therapy with midodrine and octreotide is aimed at stabilizing patients until they receive a liver transplant. Abdominal compartment syndrome as a cause of prerenal
AKI:
Abdominal
compartment
syndrome
(ACS) refers to organ dysfunction caused by intraab dominal hypertension. Intraabdominal pressure (lAP) is
Similar
to
other
causes
of
prerenal
AKI
induced
by reduced perfusion, the renal indices usually are decreased (FENa < Treat
with
1% and FEurea< 35%).
either
surgical
decompression
(trauma
patients) or high-volume paracentesis (in patients with massive ascites).
the steady state pressure concealed within the abdomi nal cavity. Abdominal perfusion pressure (APP) is calculated as the mean arterial pressure (MAP) minus the lAP (APP
=
MAP- lAP).
Elevated intraabdominal pressure reduces blood flow to the abdominal viscera. ACS is defined as a sustained
Prerenal AKI: Labs BUN:Cr ratio is typically increased to>
20.
Urine is very concentrated with osmolality > often>
400, and
700.
intraabdominal pressure >
UrineNa+ is< 20, indicating normal tubular function (and
APP <
avid reabsorption ofNa+ to increase glomerular pressure).
20 mmHg (with or without 60 mrnHg) that is associated with new organ
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