Transcript Slide 1

Acute Kidney Injury
Edward L. Barnes, MD
Chief Resident Conference
July 5, 2012
Outline for Today
• Workup
• Pre-Renal
• Intrinsic
» Tubulointerstitial Disease
» Glomerular Disease
• Post-Renal
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Initial Work Up
• Attempt to define the problem
• What is the reason for the Acute Kidney
Injury?
• Typically broken down into where the etiology
is occurring
» Pre-Renal
» Intrinsic Disease
» Post-Renal
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Acute Kidney Injury
• Which situation is worse
» Creatinine 1.1 1.6
» Creatinine 2.8  3.3
• Is a Cr of 1 always normal?
» 80 yo woman, frail with BMI 18
» 25 yo man, muscular with BMI 25
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Serum Creatinine vs. GFR
• Remember this is a non-linear relationship
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Case #1
A 65-year-old man is admitted to the hospital because of fever
and dysuria. Laboratory studies show a leukocyte count of
12,000/µL, a blood urea nitrogen level of 24 mg/dL, a serum
creatinine concentration of 1.4 mg/dL, and pyuria. Empiric
treatment with trimethoprim-sulfamethoxazole is started. Three
days later, the pyuria and fever have resolved. The leukocyte
count is 10,000/µL, blood urea nitrogen level is 24, and serum
creatinine is 1.8 mg/dL. Urinalysis shows no leukocytes, casts or
crystals.
What are some potential causes of the increase
in Cr from 1.4 to 1.8?
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Case #1
Which of the following is the most likely
explanation for the rise in serum creatinine from
1.4 mg/dL to 1.8 mg/dL?
A.
B.
C.
D.
E.
Acute interstitial nephritis
Acute pyelonephritis
Acute tubular necrosis
Obstructive uropathy
Drug effect with reduced creatinine excretion
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Case #2
A previously healthy 74-year-old man is hospitalized with
cough and chest pain. On physical examination, the blood
pressure is 148/92 mm Hg, heart rate is 75/min,
respiration rate is 18/min, and temperature is 37.8 °C
(100 °F). The left lower lung field has scattered basilar
crackles. The hematocrit is 34% and leukocytosis is
present. The serum creatinine concentration is 2.3 mg/dL.
Urinalysis shows a pH of 6.0, 1+ proteinuria, and no
hematuria or ketonuria.
What else do you want to know?
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Case #2
Which of the following is most useful in
distinguishing acute from chronic renal failure in
this patient?
A. A previous hematocrit
B. Previous serum creatinine concentration
C. Blood urea nitrogen to creatinine ratio
D. Microscopic urinalysis
E. Renal ultrasonography
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Acute Kidney Injury
• Step One: Define the Problem (History)
» Prior Creatinine Measurements
» All Medications, New Medications, Herbal
Medications, Illicit Drug use
» Recent contrast exposure
• May have to explicitly ask about imaging
» Volume loss, dehydration, decreased po
intake
» Flank Pain
» Hematuria, Dysuria, Anuria
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Acute Kidney Injury
• Step Two: Physical Exam
»
»
»
»
»
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Evaluate for dehydration
Flank Pain
Edema
Tender, lower abdominal mass
Rash
Sinus abnormalities
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Acute Kidney Injury
• Step Three: Labs and Diagnostic Studies
» Urinalysis: the liquid kidney biopsy
» Urine “Lytes”
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•
•
•
Sodium
Creatinine
Urea (if on diuretics)
Serum Chemistry
» Fractional Excretion of Na (FENa)
Urine Na x Plasma Cr
Urine Cr x Plasma Na
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Acute Kidney Injury
• Fractional Excretion of Na (FeNa)
Urine Na x Plasma Cr
Urine Cr x Plasma Na
• FeNa <1 = Pre-Renal
• FeNa >2 = Intrinsic
• FeUrea <35% = Pre-Renal
• FeUrea >35% = Intrinsic Disease
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Acute Kidney Injury
• Other Labs to consider:
»
»
»
»
»
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Urine Protein/Creatinine Ratio
ANA, ANCA
HIV, RPR
Hepatitis Panel
Complement Levels: C3, C4
SPEP/UPEP
Hansel Stain
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Urinalysis
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Color
• Rhabdomyolysis (myoglobinuria)
• Alkaptonuria
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Color
Pseudomonas
Lee J. N Engl J Med 2007;357:e14.
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Urinalysis: Protein
• Only accounts for albumin
• You may need to test for other proteins
» Bence Jones protein in suspected Light Chain
Disease or Multiple Myeloma
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Looking at the Urine
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Looking at the Urine
Red Blood Cell Casts
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Looking at the Urine
Dysmorphic Red Blood Cells
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Looking at the Urine
Uric Acid
Crystals
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Calcium
Oxalate
Crystals
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PUTTING IT ALL TOGETHER
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Case #3
48 yo woman with PMH significant for HTN
(treated with Lisinopril) presents with a chief
complaint of vomiting and weakness. Baseline
Cr is 0.8. Laboratory Studies are shown below:
Na
K
BUN
Cr
140
3.8
38
1.6
Urine Na
Urine Cr
7
65
What type of Acute Kidney injury does this
patient have?
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Case #3
• FeNa = 0.12%
Pre-Renal
Acute Kidney Injury
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Pre-Renal Acute Kidney Injury
• Causes:
»
»
»
»
»
»
Dehydration
Shock
Acute Volume Loss (bleeding)
Abdominal Compartment Syndrome
Decompensated Heart Failure
End Stage Liver Disease (Hepatorenal
syndrome)
» Renal Artery Thrombosis
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Urinalysis
• Urinalysis should be relatively normal
• If patient is dehydrated, you may see Hyaline
Casts
• Urine Sediment will otherwise be bland
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Treatment
• Correct the underlying perfusion abnormality
if possible
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Case #3
48 yo woman with PMH significant for HTN
(treated with Lisinopril) presents with a chief
complaint of vomiting and weakness. Baseline
Cr is 0.8. Laboratory Studies are shown below:
Na
K
BUN
Cr
140
3.8
38
1.6
Urine Na
Urine Cr
Urine Urea
7
65
135
How would you treat this
patient?
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Pre-Renal Acute Kidney Injury
• 48 yo woman with PMH significant for HTN
presenting with:
» Severe abdominal pain
» Guarding on exam
» Bladder pressure as measured by foley
catheter is 34 mmHg
» Cr is 1.9 (baseline 0.8)
» Urine sediment is bland
What is the diagnosis?
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Pre-Renal Acute Kidney Injury
• 48 yo woman with PMH significant for HTN
presenting with:
» Altered mental status
» Hypotension
» Blood cultures positive for Pseudomonas
aeruginosa
» Cr is 2.7 (baseline 0.8)
» Urine sediment is bland
What is the etiology of the
acute kidney injury?
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Pre-Renal Acute Kidney Injury
• 48 yo woman with PMH significant for HTN,
cirrhosis secondary to HCV presenting with:
»
»
»
»
»
»
Altered mental status
Hypotension
Anasarca
FeNa 0% (very low), Urine Na <5
Cr is 2.7 (baseline 0.8)
Urine sediment is bland
What is the etiology of the
acute kidney injury?
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Case #4
48 yo woman with PMH significant for HTN
(treated with Lisinopril and HCTZ) presents with
a chief complaint of vomiting and weakness.
Baseline Cr is 0.8. Laboratory Studies are
shown below:
Na
K
BUN
Cr
140
3.8
38
2.6
Urine Na
Urine Cr
Urine Urea
85
65
135
How would you treat this
patient?
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Case #4
• This patient is on chronic diuretic therapy,
thus you must calculate the FeUrea:
Urine Urea x Plasma Cr
Urine Cr x Plasma Urea
FeUrea= 14.21%
Pre-Renal Acute
Kidney Injury
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Case #5
48 yo woman with PMH significant for HTN
(treated with Lisinopril and HCTZ) presents with
a chief complaint of vomiting and weakness.
Baseline Cr is 0.8. Laboratory Studies are
shown below:
Na
K
BUN
Cr
140
3.8
38
2.5
Urine Na
Urine Cr
Urine Urea
65
45
265
What is the etiology of this
patient’s Acute Kidney Injury?
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Intrinsic Acute Kidney Injury
• Etiology of Intrinsic AKI:
» Acute Tubular Necrosis (ATN)
» Contrast Induced Nephropathy (CIN)
» Rhabdomyolysis (Pigment Induced
Nephropathy)
» Acute Interstitial Nephritis (AIN)
» Glomerulonephritis (multiple etiologies)
» Cholesterol Emboli
» Thrombotic Microangiopathy
» and more…
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Case
23 yo man with no PMH, but was recently
treated for Strep Throat presents with fatigue
and overall feeling poorly. Physical Exam is
normal.
Cr 2.5
FeNa 2.3%
What do you want to do next?
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Case Continued
What is your diagnosis?
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Post-Streptococcal
Glomerulonephritis
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Glomerulonephritis
• Defined by Red Blood Cell Casts in the urine
sediment
• Multiple etiologies of Glomerulonephritis
exist, will be covered in detail elsewhere
• Associations to remember:
» Most Common: IgA Nephropathy
» GN + Hemoptysis: ANCA or anti-GBM
(Goodpasture’s Syndrome)
» GN + Purpura: Think Vasculitis
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Case #6
54 yo man with PMH significant for HTN,
Hyperlipidemia, presented to the MICU after
being found down and resuscitated for
approximately 20 minutes. After 3 days, patient
has now been extubated and is doing well,
however his Creatinine continues to rise.
Creatinine on admission was 1.2, now 3.5 this
morning.
Cr 3.5
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FeNa 3.5%
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Case #6 Continued
You spin his urine and find…
What is your
diagnosis?
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Esson ML, Shrier RW. Diagnosis and Treatment of Acute Tubular
Necrosis. Ann Intern Med. 5 November 2002;137(9):744-752
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Acute Tubular Necrosis
• Risk Factors:
» Prolonged Hypotension
» Nephrotoxic Agents
• Classic description: “muddy brown casts”
• Treatment
» Remove inciting etiology (resuscitate, remove
suspected medication)
• If patient improves, suspect post ATN
diuresis to occur (may take up to 1-3 weeks)
• Some patients may progress to End Stage
Renal Disease
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Case #7
68 yo man with PMH significant for HTN and
Hyperlipidemia, admitted for a STEMI. Patient
received PCI with stent to the Right Coronary
Artery. Patient is doing well, but on day 3 of
admission, Creatinine is noted to be elevated at
1.9. Baseline Creatinine was 0.9. No new
medications other than Plavix.
FeNa: 2.5%
What is the suspected
diagnosis?
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Contrast Induced Nephropathy
• At Risk Patients:
» Diabetes Mellitus
» Chronic Kidney Disease
• Occurs in approximately 3% of the population
• Typically occurs 24-48 hours following contrast
administration
• Typically transient, improving over 1-3 weeks; however
there is potential for progression to ESRD
• Prevention
» Hydration
» Hold nephrotoxic agents (NSAIDs)
• Treatment
» supportive
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Case #8
• 68 yo man with PMH significant for HTN and
Hyperlipidemia, admitted for a STEMI.
Patient received PCI with stent to the Right
Coronary Artery. Patient is doing well,
however overnight, Cr increases from
baseline (0.9) to 2.1 and the patient develops
a new rash. No new medications other than
Plavix.
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Case #8
What is this “rash”?
Livedo Reticularis
What is the diagnosis?
Cholesterol Emboli Syndrome
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Case #9
22 yo man with no PMH presents with nausea,
vomiting, and fatigue. The patient is a member
of the wrestling team at UNC. Denies taking any
new medications or supplements.
Cr 2.9 (baseline 0.8)
FeNa 2.6%
Urine dipstick performed in your office indicates
3+ blood. You examine the urine, and the
sediment is bland, no RBC or WBC are seen.
What other labs would you want to know?
What is the diagnosis?
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Case #10
78 yo man with PMH significant for HTN, and
Benign Prostatic Hypertrophy. He has been
taking over the counter allergy medications.
Over the past 24 hours he has developed lower
abdominal pain, decreased urine output. On
laboratory studies:
Cr 2.3 (baseline 1.0)
Urine Sediment is bland
FeNa 2.5%
What is the next test that you
want to order?
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Renal Ultrasound
Presence of Hydronephrosis indicates
post-renal Acute Kidney Injury
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Post-Renal Acute Kidney Injury
• Hydronephrosis and Acute Kidney Injury is an
Emergency
• You must relieve the obstruction
» Foley Catheter
» Nephrostomy Tubes
• Next you must identify the cause of the
obstruction
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The End
Acute Kidney Injury
Pre-Renal
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Intrinsic
Post-Renal
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