05 Goldstein   Acute Renal Failure
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05 Goldstein Acute Renal Failure

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  • hyaline cast, normal finding, Prerenal.
  • muddy brown granular casts
  • epithelial cell cast (cells are larger than WBCs; have nuclei)
  • WBC cast which drug? gentamicin for SBE, motrin for RA, ASA for CAD,
  • RBC casts
  • Another pic of RBC casts; just look different

05 Goldstein   Acute Renal Failure 05 Goldstein Acute Renal Failure Presentation Transcript

  • Acute Renal Failure Deb Goldstein Argy Resident September, 2005
  • Acute Renal Failure
    • Rapid decline in the GFR over days to weeks.
    • Cr increases by >0.5 mg/dL
    • GFR <10mL/min, or <25% of normal
    • Acute Renal Insufficiency
    • Deterioration over days-wks
    • GFR 10-20 mL/min
  • Definitions
    • Anuria: No UOP
    • Oliguria: UOP<400-500 mL/d
    • Azotemia: Incr Cr, BUN
    • May be prerenal, renal, postrenal
    • Does not require any clinical findings
    • Chronic Renal Insufficiency
    • Deterioration over mos-yrs
    • GFR 10-20 mL/min, or 20-50% of normal
    • ESRD = GFR <5% of nl
    View slide
  • ARF: Signs and Symptoms
    • Hyperkalemia
    • Nausea/Vomiting
    • HTN
    • Pulmonary edema
    • Ascites
    • Asterixis
    • Encephalopathy
    View slide
  • Causes of ARF in hospitalized pts
    • 45% ATN
    • Ischemia, Nephrotoxins
    • 21% Prerenal
    • CHF, volume depletion, sepsis
    • 10% Urinary obstruction
    • 4% Glomerulonephritis or vasculitis
    • 2% AIN
    • 1% Atheroemboli
  • ARF: Focused History
    • Nausea? Vomiting? Diarrhea?
    • Hx of heart disease, liver disease, previous renal disease, kidney stones, BPH?
    • Any recent illnesses?
    • Any edema, change in
    • urination?
    • Any new medications?
    • Any recent radiology studies?
    • Rashes?
  • Physical Exam
    • Volume Status
      • Mucus membranes, orthostatics
    • Cardiovascular
      • JVD, rubs
    • Pulmonary
      • Decreased breath sounds
      • Rales
    • Rash (Allergic interstitial nephritis)
    • Large prostate
    • Extremities (Skin turgor, Edema)
  • W/U for ARF
    • Chem 7
    • Urine
      • Urine electrolytes and Urine Cr to calculate FeNa
      • Urine eosinophils
      • Urine sediment: casts, cells, protein
      • Uosm
    • Kidney U/S - r/o hydronephrosis
  • FeNa = (urine Na x plasma Cr) (plasma Na x urine Cr)
    • FeNa <1%
    • 1. PRERENAL
    • Urine Na < 20. Functioning tubules reabsorb lots of filtered Na
    • 2. ATN (unusual)
    • Postischemic dz: most of UOP comes from few normal nephrons, which handle Na appropriately
    • ATN + chronic prerenal dz (cirrhosis, CHF)
    • 3. Glomerular or vascular injury
    • Despite glomerular or vascular injury, pt may still have well-preserved tubular function and be able to concentrate Na
  • More FeNa
    • FeNa 1%-2%
    • 1. Prerenal-sometimes
    • 2. ATN-sometimes
    • 3. AIN-higher FeNa due to tubular damage
    • FeNa >2%
    • ATN
    • Damaged tubules can't reabsorb Na
  • Calculating FeNa after pt has gotten Lasix...
    • Caution with calculating FeNa if pt has gotten Loop Diuretics in past 24-48 h
    • Loop diuretics cause natriuresis (incr urinary Na excretion) that raises U Na-even if pt is prerenal
    • So if FeNa>1%, you don’t know if this is because pt is euvolemic or because Lasix increased the U Na
    • So helpful if FeNa still <1%, but not if FeNa >1%
    • 1. Fractional Excretion of Lithium (endogenous)
    • 2. Fractional Excretion of Uric Acid
    • 3. Fractional Excretion of Urea
  • A 22yo male with sickle cell anemia and abdominal pain who has been vomiting nonstop for 2 days. BUN=45, Cr=2.2.
    • A. ATN
    • B. Glomerulo-nephritis
    • C. Dehydration
    • D. AIN from NSAIDs
  • Prerenal ARF
    • Hyaline casts can be seen in normal pts
      • NOT an abnormal finding
    • UA in prerenal ARF is normal
    • Prerenal: causes 21% of ARF in hosp. pts
    • Reversible
    • Prevent ATN with volume replacement
      • Fluid boluses or continuous IVF
      • Monitor Uop
  • Prerenal causes
    • Intravascular volume depletion
      • Hemorrhage
      • Vomiting, diarrhea
      • “ Third spacing”
      • Diuretics
    • Reduced Cardiac output
      • Cardiogenic shock, CHF, tamponade, huge PE....
    • Systemic vasodilation
      • Sepsis
      • Anaphylaxis, Antihypertensive drugs
    • Renal vasoconstriction
      • Hepatorenal syndrome
  • Intrinsic ARF
    • Tubular (ATN)
    • Interstitial (AIN)
    • Glomerular (Glomerulonephritis)
    • Vascular
  • You evaluate a 57yo man w/ oliguria and rapidly increasing BUN, Cr.
    • ATN
    • Acute glomerulonephritis
    • Acute interstitial nephritis
    • Nephrotic Syndrome
  • ATN
    • Muddy brown granular casts (last slide)
    • Renal tubular epithelial cell casts (below)
  • More ATN
    • Broad casts (form in dilated, damaged tubules)
  • ATN Causes
    • 1. Hypotension
    • Relative low BP
    • May occur immediately after low BP episode or up to 7 days later!
    • 2. Post-op Ischemia
    • Post-aortic clamping, post-CABG
    • 3. Crystal precipitation
    • 4. Myoglobinuria (Rhabdo)
    • 5. Contrast Dye
      • ARF usually 1-2 days after test
    • 6. Aminoglycosides (10-26%)
  • ATN—What to do
    • Remove any offending agent
      • IVF
      • Try Lasix if euvolemic pt is not peeing
      • Dialysis
    • Most pts return to baseline Cr in 7-21 days
  • >20:1 10-15:1 BUN/Cr Cr improves with IVF Cr won’t improve much Response to volume Normal epi cells, granular casts UA UNa<20 FeNa<1% UNa>40 FeNa >2% U Na, FeNa increases slower than 0.3 /day increases at 0.3-0.5 /day Cr Prerenal ATN
  • Which UA is most compatible w/contrast-induced ATN?
    • Spec grav 1.012, 20-30 RBC, 15-20 WBC, +Eos
    • Spec grav 1.010, 1-3 WBC, 5-10 renal tubular cells, many granular casts, occasional renal tubular cell casts, no eos
    • Spec grav 1.012, 5-10 RBC, 25-50 WBC, many bact, occasional fine granular casts, no eos
    • Spec grav 1.020, 10-20 RBC, 2-4 WBC, 1-3 RBC casts, no eos
  • ATN
    • B. Spec grav 1.010, 1-3 WBC, 5-10 renal tubular cells, many granular casts, occasional renal tubular cell casts, no eos
    • Dilute urine: failure to concentrate urine
    • No RBC casts or WBC casts in ATN
    • Eos classically in AIN or renal atheroemboli, but nonspecific
  • 56yo woman with previously normal renal function now has BUN=24, Cr 1.8. Which drug is responsible?
    • Indinavir for her HIV
    • Gentamicin for her SBE
    • Motrin for her OA
    • Cyclosporin for her SLE
  • WBC Casts
    • Cells in the cast have nuclei
    • (unlike RBC casts)
    • Pathognomonic for Acute Interstitial Nephritis
  • Acute Interstitial Nephritis
    • 70% Drug hypersensitivity
    • 30% Antibiotics: PCNs (Methicillin), Cephalosporins, Cipro
    • Sulfa drugs
    • NSAIDs
    • Allopurinol...
    • 15% Infection
    • Strep, Legionella, CMV, other bact/viruses
    • 8% Idiopathic
    • 6% Autoimmune Dz (Sarcoid, Tubulointerstitial nephritis/Uveitis)
  • AIN from Drugs
    • Renal damage is NOT dose-dependent
    • May take wks after initial exposure to drug
    • Up to 18 mos to get AIN from NSAIDS!
    • But only 3-5 d to develop AIN after second exposure to drug
    • Fever (27%)
    • Serum Eosinophilia (23%)
    • Maculopapular rash (15%)
    • Bland sediment or WBCs, RBCs, non-nephrotic proteinuria
    • WBC Casts are pathognomonic!
    • Urine eosinophils on Wright’s or Hansel’s Stain
      • Also see urine eos in RPGN, renal atheroemboli...
  • AIN Management
    • Remove offending agent
    • Most patients recover full kidney function in 1 year
    • Poor prognostic factors
      • ARF > 3 weeks
      • Advanced age at onset
  • You evaluate a 32yo woman with HTN, oliguria, and rapidly increasing Cr, BUN. You spin her urine:
    • ATN
    • Acute glomerulonephritis
    • Acute interstitial nephritis
    • Nephrotic Syndrome
  • Acute Glomerulonephritis
    • RBC casts : cells have no nuclei
    • Casts in urine: think INTRINSIC renal dz
    • If she has Lupus w/recent viral prodrome, think Rapidly Progressive Glomerulonephritis
    • If she had a sore throat 10 days ago, think Postinfectious Proliferative Glomerulonephritis
  • What are these?
  • Glomerular Dz
    • Hematuria (dysmorphic RBCs)
    • RBC casts
    • Lipiduria (increased glomerular permeability)
    • Proteinuria (may be in nephrotic range)
    • Fever, rash, arthralgias, pulmonary sx
    • Elevated ESR, low complement levels
    • Type 1: Anti-GBM dz
    • Type 2: Immune complex
    • IgA nephropathy
    • Postinfectious glomerulonephritis
    • Lupus nephritis
    • Mixed cryoglobulinemia
    • Type 3: Pauci-immune
    • Necrotizing glomerulonephritis (often ANCA-positive, assoc. w/vasculitis)
    • Can present with viral-like prodrome
    • Myalgias, arthralgias, back pain, fever, malaise
    • Kidney bx : Extensive cellular crescents with or w/o immune complexes
    • Can develop ESRD in days to weeks.
    • Treat w/glucocorticoids & cyclophosphamide.
    Rapidly Progressive Glomerulonephritis
    • Usually after strep infxn of upper respiratory tract or skin – 8-14 day latent period
      • Can also occur in subacute bacterial endocarditis, visceral abscesses, osteomyelitis, bacterial sepsis
    • Hematuria, HTN, edema, proteinuria
    • Positive antistreptolysin O titer (90% upper respiratory and 50% skin)
    • Treatment is supportive
      • Screen family members with throat culture and treat with antibiotics if necessary
    Postinfectious Proliferative Glomerulonephritis
  • A 19yo woman with Breast Cancer s/p chemo in the ER has weakness, fever, rash. WBC=15.4, Hct 24, Cr 2.9, LDH 600, CK=600. UA=3+ prot, 3+blood, 20 RBC. What next test do you order? What’s her likely dx?
    • Nephrotic Syn
    • Systemic Vasculitis
    • Acute Glomerulonephritis
    • Hemolytic-Uremic Syn
    • Rhabdomyolysis
  • TTP
    • Order blood smear to r/o TTP
    • TTP associated with malignancy, chemo
    • TTP may mimic Glomerulonephritis on UA (RBCs, WBCs)
    • Thrombocytopenia, anemia not consistent with nephrotic or nephritic syndrome
    • Need CK in the thousands to cause ARF
  • Microvascular ARF
    • TTP/HUS
    • HELLP syndrome
    • Platelets form thrombi and deposit in kidneys  Glomerular capillary occlusion or thrombosis
    • Plasma exchange, steroids, Vincristine, IVIG, splenectomy....
  • Macrovascular ARF
    • Aortic Aneurysm
    • Renal artery dissection or thrombosis
    • Renal vein thrombus
    • Atheroembolic disease
      • New onset or accelerated HTN?
      • Abdominal bruits, reduced femoral pulses?
      • Vascular disease?
      • Embolic source?
        • Renal Artery Stenosis
        • Contrast-Induced Nephropathy
        • C. Abdominal Aortic Aneurysm
        • D. Cholesterol Atheroemboli
    Your 68yo male inpatient with baseline Cr=1.2 had negative cardiac cath 4 days ago, now Cr=1.8 and blanching rash.
  • Why do his toes look like this?
  • Renal Atheroembolic Dz
    • 1% of Cardiac caths: atheromatous debris scraped from the aortic wall will embolize
      • Retinal
      • Cerebral
      • Skin (Livedo Reticularis, Purple toes)
      • Renal (ARF)
      • Gut (Mesenteric ischemia)
    • Unlike in Contrast-Induced Nephropathy, Cr will NOT improve with IVF
    • Diagnosis of exclusion: will NOT show up on MRI or Renal U/S; WILL show up on renal bx
    • Tx: supportive
  • Post-Renal ARF
    • Urethral obstruction: prostate, urethral
    • stricture.
    • Bladder calculi or neoplasms.
    • Pelvic or retroperitoneal neoplams.
    • Bilateral ureteral obstruction (neoplasm,
    • calculi).
    • Retroperitoneal fibrosis.
  • “Doc, your pt hasn’t peed in 5 hrs....what do you want to do?”
    • Examine pt: Dry? Septic (vasodilated)?
    • Flush foley (sediment can obstruct outflow)
    • Check I/Os (has she been drinking?)
    • Give IV BOLUS (250-500cc IVF), see if pt pees in next 30-60 min
      • If she pees, then she was dry
      • If she doesn’t pee, then she’s either REALLY dry or in renal failure
    • Check UA, UCx, urine lytes
    • Consider Renal U/S if reasonable
  • You’re called to the ER to see...
    • A 35yo woman with previously normal renal function now with BUN=60, Cr=3.5. Do you call the Renal fellow to dialyze this pt?
    • What if her K=5.9?
    • What if her K=7.8?
  • Indications for acute dialysis
    • AEIOU
    • Acidosis (metabolic)
    • Electrolytes (hyperkalemia)
    • Ingestion of drugs/Ischemia
    • Overload (fluid)
    • Uremia
    • You admit this pt to telemetry and aggressively hydrate her.
    • You recheck labs 6h later and BUN=85, Cr=4.2. Suddenly the pt starts to seize.
    • Now what?
  • Uremia—So what?
    • General
      • Fatigue, weakness
      • Pruritis
    • Mental status change
      • Uremic encephalopathy
      • Seizures
      • Asterixis
    • GI disturbance
      • Anorexia, early satiety, N/V,
    • Uremic Pericarditis
    • Plt dysfunction/bleeding
  • A pt with chronic lung disease has acute pleuritic pain and desats to 92%RA. You want to r/o PE but her Cr=1.4. Can you get a CT with IV contrast?
    • Send her for Stat CT with IV contrast
    • Send her for Stat CT without IV contrast
    • C. Just give her heparin
    • Begin IV hydration
    • Begin pre-procedure Mannitol
    • Get a VQ scan instead
  • Contrast-Induced Nephrotoxicity
    • Cr increases by 25% or >0.05 post-procedure
    • Contrast causes renal vasoconstriction  renal hypoxia
    • Iodine itself may be renally toxic
    • If Cr>1.4, use pre-procedure prophylaxis
  • Pre-Procedure Prophylaxis
    • 1. IVF ( 0.9NS)
    • 1-1.5 mg/kg/hour x12 hours prior to procedure and 6-12 hours after
    • 2. Mucomyst (N-acetylcysteine)
    • Free radical scavenger; prevents oxidative tissue damage
    • 600mg po BID x 4 doses (2 before procedure, 2 after)
    • 3. Bicarbonate (JAMA 2004)
    • Alkalinizing urine should reduce renal medullary damage
    • D5W with 3 amps HCO3; bolus 3.5 mL/kg 1 hour preprocedure, then 1mL/kg/hour for 6 hours postprocedure
    • 4. Possibly helpful? Fenoldopam, Dopamine
    • 5. Not helpful! Diuretics, Mannitol