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

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

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