Acute Renal Failure.ppt

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1、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 normalAcute Renal Insufficiency Deterioration over days-wks GFR 10-20 mL/min,Definitions,Anuria: No UOP Oliguria: UOP400-

2、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,ARF: Signs and Symptoms,Hyperkalemia Nausea/Vomiting HTN Pulmonary edema Ascites A

3、sterixis Encephalopathy,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,

4、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 inter

5、stitial 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. P

6、RERENAL 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

7、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 damageFeNa 2% ATN Damaged tubules cant reabsorb Na,Calculating FeNa after pt has gotten Lasix.,Caution with calculating FeNa if pt ha

8、s 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 FeNa1%, you dont know if this is because pt is euvolemic or because Lasix increased the U Na So helpful if FeNa still 1% 1. Fractional Excretion of Lithi

9、um (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

10、 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” Diureti

11、cs 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/ oliguri

12、a 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

13、 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%),ATNWhat to do,Remove any offending agent IVF Try Lasix if

14、euvolemic pt is not peeing Dialysis Most pts return to baseline Cr in 7-21 days,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 gr

15、av 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

16、 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,C

17、ells 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% I

18、diopathic 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 drugFever (27%) Serum Eosinophilia (23%

19、) Maculopapular rash (15%)Bland sediment or WBCs, RBCs, non-nephrotic proteinuria WBC Casts are pathognomonic! Urine eosinophils on Wrights or Hansels Stain Also see urine eos in RPGN, renal atheroemboli.,AIN Management,Remove offending agent Most patients recover full kidney function in 1 year Poor

20、 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

21、: 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 glome

22、rular 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

23、glomerulonephritis (often ANCA-positive, assoc. w/vasculitis) Can present with viral-like prodrome Myalgias, arthralgias, back pain, fever, malaiseKidney bx : Extensive cellular crescents with or w/o immune complexes Can develop ESRD in days to weeks. Treat w/glucocorticoids & cyclophosphamide.,Rapi

24、dly 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% uppe

25、r 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=6

26、00. UA=3+ prot, 3+blood, 20 RBC. What next test do you order? Whats 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)

27、 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 kidneysGlomerular capillary occlusion or thrombosis Plasma exchange, steroids, Vincristine, IVIG, splenec

28、tomy,Macrovascular ARF,Aortic Aneurysm Renal artery dissection or thrombosis Renal vein thrombus Atheroembolic diseaseNew onset or accelerated HTN? Abdominal bruits, reduced femoral pulses? Vascular disease? Embolic source?,Renal Artery Stenosis Contrast-Induced Nephropathy C. Abdominal Aortic Aneur

29、ysm 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 Cerebr

30、al 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, ur

31、ethralstricture.Bladder calculi or neoplasms.Pelvic or retroperitoneal neoplams.Bilateral ureteral obstruction (neoplasm, calculi).Retroperitoneal fibrosis.,“Doc, your pt hasnt peed in 5 hrswhat do you want to do?”,Examine pt: Dry? Septic (vasodilated)? Flush foley (sediment can obstruct outflow) Ch

32、eck 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 doesnt pee, then shes either REALLY dry or in renal failure Check UA, UCx, urine lytes Consider Renal U/S if reasonable,Youre called to the ER to see.,A 35yo woman w

33、ith 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 thi

34、s 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?,UremiaSo what?,General Fatigue, weakness Pruritis Mental status change Uremic encephalopathy Seizures Asterixis GI disturbance Anorexia, early satiety, N/V, Uremic

35、 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 h

36、ydration 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 Cr1.4, use pre-procedure prophylaxis,Pre-Procedure Prophylaxis,1. IVF ( 0.

37、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,