ACUTE RENAL FAILURE Pirouz Daeihagh, M.D. Internal medicine/Nephrology Wake Forest University School of Medicine
  Background   <ul><li>Common in Hospitalized patients </li></ul><ul><li>Associated with high Morbidity and Mortality </li...
 
 
Acute Renal Failure <ul><li>Sudden decrease in function (hours-days) </li></ul><ul><li>Often multifactorial </li></ul><ul>...
 
Acute Renal Failure   Diagnosis <ul><li>Laboratory Evaluation: </li></ul><ul><ul><li>Scr,  More reliable marker of GFR </l...
Acute Renal Failure Diagnosis (cont’d) <ul><li>Urinalysis </li></ul><ul><ul><li>Unremarkable in pre and post renal causes ...
Acute Renal Failure Diagnosis (cont’d) <ul><li>Urinary Indices; </li></ul><ul><ul><li>FE Na = (U/P)  Na  X (P/U) Cr X 100 ...
 
Prerenal Azotemia <ul><li>Nearly as common as ATN (think of as early part of the disease spectrum) </li></ul><ul><li>Diagn...
 
 
 
Acute Renal Failure   Etiologies <ul><li>Acute Tubular Necrosis </li></ul><ul><ul><li>Most common cause of intrinsic cause...
Acute Tubular Necrosis (ATN) -- 2 <ul><li>Diagnose by history,    FE Na  (>2%)  </li></ul><ul><li>sediment with coarse gr...
 
Contrast nephropathy <ul><li>12-24 hours post exposure, peaks in 3-5 days </li></ul><ul><li>Non-oliguric, FE Na <1% !! </l...
Rhabdomyolytic ARF <ul><li>Diagnose with    serum CPK (usu. > 10,000), urine dipstick (+) for blood, without RBCs on micr...
 
Acute Glomerulonephritis <ul><li>Rare in the hospitalized patient </li></ul><ul><li>Most common types: acute post-infectio...
Acute Glomerulonephritis (2) <ul><li>If diagnosis is post-infectious, disease is usually self-limited, and supportive care...
Atheroembolic ARF <ul><li>Associated with emboli of fragments of atherosclerotic plaque from aorta and other large arterie...
Acute Interstitial Nephritis  <ul><ul><li>Usually drug induced </li></ul></ul><ul><ul><ul><li>methicillin, rifampin, NSAID...
Acute Renal Failure  Etiologies <ul><li>Post-Renal </li></ul><ul><ul><li>Bladder outlet obstruction </li></ul></ul><ul><ul...
Prevention <ul><li>What works? </li></ul><ul><li>Maintenance of euvolemia </li></ul><ul><li>Avoidance of nephrotoxins when...
Prevention <ul><li>What doesn’t work? </li></ul><ul><li>Empiric use of: </li></ul><ul><ul><li>Diuretics (i.e., Furosemide,...
Acute Renal Failure   Treatment <ul><li>Water and sodium restriction </li></ul><ul><li>Protein restriction </li></ul><ul><...
Hyperkalemia <ul><li>Highly Arrhythmogenic </li></ul><ul><ul><li>Usually with progressive EKG changes </li></ul></ul><ul><...
 
Dialysis Indications <ul><li>Refractory hyperkalemia </li></ul><ul><li>Metabolic acidosis </li></ul><ul><li>Volume overloa...
 
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16 Daeihagh Acute Renal Failure

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16 Daeihagh Acute Renal Failure

  1. 2. ACUTE RENAL FAILURE Pirouz Daeihagh, M.D. Internal medicine/Nephrology Wake Forest University School of Medicine
  2. 3. Background <ul><li>Common in Hospitalized patients </li></ul><ul><li>Associated with high Morbidity and Mortality </li></ul><ul><li>Often Multifactorial </li></ul><ul><li>Identifiable risk factors. </li></ul>
  3. 6. Acute Renal Failure <ul><li>Sudden decrease in function (hours-days) </li></ul><ul><li>Often multifactorial </li></ul><ul><li>Pre-renal and intrinsic renal causes 70% </li></ul><ul><li>oliguric UOP < 400 ml </li></ul><ul><li>Non-oliguric (up to 65%) </li></ul><ul><li>Associated with high mortality and morbidity </li></ul>
  4. 8. Acute Renal Failure Diagnosis <ul><li>Laboratory Evaluation: </li></ul><ul><ul><li>Scr, More reliable marker of GFR </li></ul></ul><ul><ul><ul><li>Falsely elevated with Septra, Cimetidine </li></ul></ul></ul><ul><ul><ul><li>small change reflects large change in GFR </li></ul></ul></ul><ul><ul><li>BUN, generally follows Scr increase </li></ul></ul><ul><ul><ul><li>Elevation may be independent of GFR </li></ul></ul></ul><ul><ul><ul><ul><li>Steroids, GIB, Catabolic state, hypovolemia </li></ul></ul></ul></ul><ul><ul><li>BUN/Cr helpful in classifying cause of ARF </li></ul></ul><ul><ul><ul><li>ratio> 20:1 suggests prerenal cause </li></ul></ul></ul><ul><ul><ul><li>ratio 10-15:1 suggests intrinsic renal cause </li></ul></ul></ul>
  5. 9. Acute Renal Failure Diagnosis (cont’d) <ul><li>Urinalysis </li></ul><ul><ul><li>Unremarkable in pre and post renal causes </li></ul></ul><ul><ul><li>Differentiates ATN vs. AIN. vs. AGN </li></ul></ul><ul><ul><ul><li>Muddy brown casts in ATN </li></ul></ul></ul><ul><ul><ul><li>WBC casts in AIN </li></ul></ul></ul><ul><ul><li>Hansel stain for Eosinophils </li></ul></ul>
  6. 10. Acute Renal Failure Diagnosis (cont’d) <ul><li>Urinary Indices; </li></ul><ul><ul><li>FE Na = (U/P) Na X (P/U) Cr X 100 </li></ul></ul><ul><ul><ul><li>FENa < 1% C/W Pre-renal state </li></ul></ul></ul><ul><ul><ul><ul><li>May be low in selected intrinsic cause </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Contrast nephropathy </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Acute GN </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Myoglobin induced ATN </li></ul></ul></ul></ul></ul><ul><ul><ul><li>FENa> 1% C/W intrinsic cause of ARF </li></ul></ul></ul>
  7. 12. Prerenal Azotemia <ul><li>Nearly as common as ATN (think of as early part of the disease spectrum) </li></ul><ul><li>Diagnose by history and physical exam </li></ul><ul><ul><li>N/V, Diarrhea, Diuretic use,... </li></ul></ul><ul><li>low FE Na (<1%) </li></ul><ul><li>high BUN/creat ratio, normal urinary sediment </li></ul><ul><li>Treat by correction of predisposing factors </li></ul>
  8. 16. Acute Renal Failure Etiologies <ul><li>Acute Tubular Necrosis </li></ul><ul><ul><li>Most common cause of intrinsic cause of ARF </li></ul></ul><ul><ul><li>Often multifactorial </li></ul></ul><ul><ul><li>Non-oliguria carries better prognosis </li></ul></ul><ul><ul><li>Ischemic ATN: </li></ul></ul><ul><ul><ul><li>Hypotension, sepsis, prolonged pre-renal state </li></ul></ul></ul><ul><ul><li>Nephrotoxic ATN: </li></ul></ul><ul><ul><ul><li>Contrast, Antibiotics, Heme proteins </li></ul></ul></ul>
  9. 17. Acute Tubular Necrosis (ATN) -- 2 <ul><li>Diagnose by history,  FE Na (>2%) </li></ul><ul><li>sediment with coarse granular casts, RTE cells </li></ul><ul><li>Treatment is supportive care. </li></ul><ul><ul><li>Maintenance of euvolemia (with judicious use of diuretics, IVF, as necessary) </li></ul></ul><ul><ul><li>Avoidance of hypotension </li></ul></ul><ul><ul><li>Avoidance of nephrotoxic medications (including NSAIDs and ACE-I) when possible </li></ul></ul><ul><ul><li>Dialysis, if necessary </li></ul></ul><ul><li>80% will recover, if initial insult can be reversed. </li></ul>
  10. 19. Contrast nephropathy <ul><li>12-24 hours post exposure, peaks in 3-5 days </li></ul><ul><li>Non-oliguric, FE Na <1% !! </li></ul><ul><li>RX/Prevention: 1/2 NS 1 cc/kg/hr 12 hours pre/post </li></ul><ul><li>Mucomyst 600 BID pre/post (4 doses) </li></ul><ul><li>Risk Factors: CRF, Hypovolemia. </li></ul>
  11. 20. Rhabdomyolytic ARF <ul><li>Diagnose with  serum CPK (usu. > 10,000), urine dipstick (+) for blood, without RBCs on microscopy, pigmented granular casts </li></ul><ul><li>Common after trauma (“crush injuries”), seizures, burns, limb ischemia occasionally after IABP or cardiopulmonary bypass </li></ul><ul><li>Treatment is largely supportive care. </li></ul><ul><li>Alkalinization of urine . </li></ul>
  12. 22. Acute Glomerulonephritis <ul><li>Rare in the hospitalized patient </li></ul><ul><li>Most common types: acute post-infectious GN, “crescentic” RPGN </li></ul><ul><li>Diagnose by history, hematuria, RBC casts, proteinuria (usually non-nephrotic range), low serum complement in post-infectious GN), RPGN often associated with anti-GBM or ANCA </li></ul><ul><li>Usually will need to perform renal biopsy </li></ul>
  13. 23. Acute Glomerulonephritis (2) <ul><li>If diagnosis is post-infectious, disease is usually self-limited, and supportive care is usually all that is necessary. </li></ul><ul><li>For RPGN, may need immunosuppressive therapy with steroids ± Cytoxan, plasmapheresis (if assoc. with anti-GBM) </li></ul>
  14. 24. Atheroembolic ARF <ul><li>Associated with emboli of fragments of atherosclerotic plaque from aorta and other large arteries </li></ul><ul><li>Diagnose by history, physical findings (evidence of other embolic phenomena--CVA, ischemic digits, “blue toe” syndrome, etc), low serum C3 and C4, peripheral eosinophilia, eosinophiluria, rarely WBC casts </li></ul><ul><li>Commonly occur after intravascular procedures or cannulation (cardiac cath, CABG, AAA repair, etc.) </li></ul>
  15. 25. Acute Interstitial Nephritis <ul><ul><li>Usually drug induced </li></ul></ul><ul><ul><ul><li>methicillin, rifampin, NSAIDS </li></ul></ul></ul><ul><ul><li>Develops 3-7 days after exposure </li></ul></ul><ul><ul><li>Fever, Rash , and eosinophilia common </li></ul></ul><ul><ul><li>U/A reveals WBC, WBC casts, + Hansel stain </li></ul></ul><ul><ul><li>Often resolves spontaneously </li></ul></ul><ul><ul><li>Steroids may be beneficial ( if Scr>2.5 mg/dl) </li></ul></ul>
  16. 26. Acute Renal Failure Etiologies <ul><li>Post-Renal </li></ul><ul><ul><li>Bladder outlet obstruction </li></ul></ul><ul><ul><ul><li>BPH, intrapelvic pathology </li></ul></ul></ul><ul><ul><li>Crystalluria </li></ul></ul><ul><ul><ul><li>Acyclovir, Indanivir, Uric Acid </li></ul></ul></ul><ul><ul><li>Papillary tip necrosis </li></ul></ul><ul><ul><ul><li>DM with pyelonephritis </li></ul></ul></ul><ul><ul><ul><li>Analgesic abuse </li></ul></ul></ul><ul><ul><ul><li>Sickle cell disease </li></ul></ul></ul>
  17. 27. Prevention <ul><li>What works? </li></ul><ul><li>Maintenance of euvolemia </li></ul><ul><li>Avoidance of nephrotoxins when possible </li></ul><ul><ul><li>NSAIDs, aminoglycoside, Amphotericin, IV contrast </li></ul></ul><ul><li>BP control--avoidance of excessive hypo- or hypertension </li></ul>
  18. 28. Prevention <ul><li>What doesn’t work? </li></ul><ul><li>Empiric use of: </li></ul><ul><ul><li>Diuretics (i.e., Furosemide, Mannitol) </li></ul></ul><ul><ul><li>Dopamine (or Dopamine agonists such as Fenoldopam) </li></ul></ul><ul><ul><li>Calcium-channel blockers </li></ul></ul>
  19. 29. Acute Renal Failure Treatment <ul><li>Water and sodium restriction </li></ul><ul><li>Protein restriction </li></ul><ul><li>Potassium and phosphate restriction </li></ul><ul><li>Adjust medication dosages </li></ul><ul><li>Avoidance of further insults </li></ul><ul><ul><li>BP support </li></ul></ul><ul><ul><li>Nephrotoxins </li></ul></ul>
  20. 30. Hyperkalemia <ul><li>Highly Arrhythmogenic </li></ul><ul><ul><li>Usually with progressive EKG changes </li></ul></ul><ul><ul><ul><li>Peaked T waves ---> Widened QRS--> Sinus wave </li></ul></ul></ul><ul><ul><li>K> 5.5 meq/L needs evaluation/intervention </li></ul></ul><ul><ul><li>Usually in setting of Decrease GFR but: </li></ul></ul><ul><ul><ul><li>medication also a common cause </li></ul></ul></ul><ul><ul><ul><ul><li>ACEI </li></ul></ul></ul></ul><ul><ul><ul><ul><li>NSAIDS </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Septra, Heparin </li></ul></ul></ul></ul>
  21. 32. Dialysis Indications <ul><li>Refractory hyperkalemia </li></ul><ul><li>Metabolic acidosis </li></ul><ul><li>Volume overload </li></ul><ul><li>Mental status changes </li></ul>

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