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Acute Renal FailureAka: Renal Failure, Azotemia, Uremia, Acute Tubular Necrosis, Acute Intrinsic Renal Failure

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  1. See Also
    1. Prerenal Failure
    2. Postrenal Failure
    3. Chronic Renal Failure
  2. Epidemiology
    1. Acute Tubular Necrosis accounts for 20-30% of ARF
  3. Causes
    1. See Acute Renal Failure Causes
  4. Pathogenesis
    1. Types: Extrarenal Conditions
      1. Prerenal Failure
        1. Decreased renal perfusion
        2. Examples: Dehydration, CHF, Liver failure
      2. Postrenal Failure
        1. Renal outflow obstruction
        2. Examples: BPH, Genitourinary tumors
    2. Types: Intrarenal Conditions
      1. Vascular Injury
        1. Afferent arteriolar vasoconstriction
          1. Results in decreased driving force
          2. Decreased Glomerular filtration
        2. Types
          1. Microvascular (Small vessel thrombosis)
          2. Macrovascular (e.g. Renal Artery Stenosis)
      2. Glomerulonephritis
        1. Associated with Hematuria and Proteinuria
      3. Acute Interstitial Nephritis
        1. Due to allergic or autoimmune diseases
      4. Tubular Injury and Acute Tubular Necrosis
        1. Mechanism
          1. Tubules injured in most but not all acute failure
          2. Obstruction
            1. Abnormal material inspissates and plugs flow
          3. Back-leak
            1. Tubular cells loose integrity
            2. Back-leaks ultrafiltrate
            3. Results in poor waste clearance
        2. Course (3 phases)
          1. Initiation phase (minutes to hours)
            1. Starts with well functioning kidney
            2. Kidney bombarded by potential toxins
          2. Maintenance phase
            1. Established loss of Renal Function
            2. Kidney unresponsive to simple interventions
          3. Recovery phase (weeks to months)
            1. Complete recovery in Acute Tubular Necrosis
    3. Specific Examples
      1. Intravenous Contrast Related Acute Renal Failure
      2. Renal Ischemia
        1. Tubular obstruction and back-leak
      3. Aminoglycoside Antibiotics
        1. Decreased Glomerular Filtration Rate
        2. Tubular cell injury
      4. Rhabdomyolysis
        1. Decreased afferent blood flow
        2. Renal tubular obstruction
  5. Risk Factors
    1. See Acute Renal Failure Risk
  6. Signs
    1. Aortic aneurysm
    2. Skin
      1. Rash (Drug-induced Interstitial Nephritis)
      2. Palpable Purpura (Vasculitis)
      3. Non-palpable Purpura
        1. Thrombotic Thrombocytopenic Purpura (TTP)
        2. Hemolytic Uremic Syndrome (HUS)
      4. Livido reticularis
  7. Labs
    1. Renal Function: Criteria for acute renal failure
      1. Serum Creatinine rises >0.3 on 2 contiguous days or
      2. Serum Creatinine rises >0.5 mg/dl or
      3. Serum Creatinine rises >50% above baseline or
      4. Calculated GFR falls >50% below baseline
    2. Fractional Excretion of Sodium (FENa)
      1. Requires urine sample prior to IV fluids, Diuretics
      2. FENa >1%: Acute tubular necrosis
      3. FENa <1%: Prerenal Failure
        1. Kidney still able to concentrate urine
    3. Complete Blood Count (CBC)
      1. Platelets decreased in Purpura (see above)
      2. Eosinophils increased in interstitial disease
    4. Urinalysis with Urine sediment examination
      1. Urine Specific Gravity
        1. Prerenal Failure: Specific Gravity >1.020
        2. Intrarenal Failure: Specific Gravity 1.010 - 1.020
      2. Vascular disease
        1. Urine RBCs often present
      3. Glomerulonephritis
        1. Urine RBCs
        2. Granular casts
        3. Proteinuria
      4. Interstitial Nephritis
        1. Pyuria
        2. Eosinophils
        3. White Blood Cell and Eosinophil casts
      5. Drug hypersensitivity nephritis
        1. Eosinophils
      6. Tubular Necrosis
        1. Pigmented granular casts
        2. Tubular epithelial cells
        3. Granular casts
      7. Prerenal Failure
        1. Hyaline Casts
    5. Autoimmune Testing for Glomerular Disease
      1. Antinuclear Antibody (ANA)
      2. Antineutrophil Cytoplasmic Antibody
      3. Antiglomerular basement membrane Antibody
    6. Percutaneous Renal Biopsy
      1. Indicated for Glomerular or Interstitial disease
  8. Radiology: Renal Ultrasound
    1. Intrarenal Failure: May show parenchymal abnormality
    2. Postrenal Failure: Hydronephrosis
  9. Management
    1. See Acute Renal Failure Management
  10. Prevention
    1. See Intravenous Contrast Related Acute Renal Failure
  11. Reference:
    1. Needham (2005) Am Fam Physician 72:1739
    2. Singri (2003) Acute Renal Failure 289:747
    3. Wilkes (1986) Am J Med 80:1129
    4. Anderson (8/15/1993) Hospital Practice, p. 61-75

Kidney Failure, Acute (C0022660)

Definition (MSH)A severe stage of acute renal insufficiency, characterized by the sudden decrease in GLOMERULAR FILTRATION RATE to less than 15 ml per min, sometime to less than 1 to 2 ml per min. It is usually associated with OLIGURIA; EDEMA; and increase in BLOOD UREA NITROGEN and serum CREATININE concentrations.
Definition (CSP)clinical syndrome characterized by a sudden decrease in glomerular filtration rate, usually associated with oliguria and always associated with biochemical consequences of the reduction in glomerular filtration rate such as a rise in blood urea nitrogen (BUN) and serum creatinine concentrations.
ConceptsDisease or Syndrome (T047)
ICD9584, 584.9
EnglishAcute and unspecified renal failure, ACUTE KIDNEY FAILURE, Acute Renal Failure, Acute renal failure syndrome, Acute Renal Failures, FAILURE KIDNEY ACUTE, KIDNEY FAILURE ACUTE, RENAL FAILURE ACUTE, RENAL SHUTDOWN ACUTE
CreditsDerived from the NIH UMLS (Unified Medical Language System)


Uremia (C0041948)

Definition (MSH)A clinical syndrome associated with the retention of renal waste products or uremic toxins in the blood. It is usually the result of RENAL INSUFFICIENCY. Most uremic toxins are end products of protein or nitrogen CATABOLISM, such as UREA or CREATININE. Severe uremia can lead to multiple organ dysfunctions with a constellation of symptoms.
Definition (CSP)excess in the blood of urea, creatinine and other nitrogenous end products of protein and aminoacid metabolism; also, the constellation of signs and symptoms of chronic renal failure.
ConceptsDisease or Syndrome (T047)
ICD9586
EnglishURAEMIA, Uremia, UREMIA OF RENAL ORIGIN, Uremias
Spanishuremia
CreditsDerived from the NIH UMLS (Unified Medical Language System)


Azotemia (C0242528)

Definition (MSH)A biochemical abnormality referring to an elevation of BLOOD UREA NITROGEN and CREATININE. Azotemia can be produced by KIDNEY DISEASES or other extrarenal disorders. When azotemia becomes associated with a constellation of clinical signs, it is termed UREMIA.
ConceptsDisease or Syndrome (T047)
EnglishAzotemia
CreditsDerived from the NIH UMLS (Unified Medical Language System)



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