ACUTE RENAL FAILURE

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ACUTE RENAL FAILURE

• JAKUB ZÁVADA
• KLINIKA NEFROLOGIE 1.LF UK

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ACUTE RENAL FAILURE (ARF)

• ARF IS A CLINICAL SYNDROME CHARACTERIZED BY A
  RAPID DECLINE IN GLOMERULAR FILTRATION RATE (OVER
  HOURS TO WEEKS)
• ARF IS ACCOMPANIED BY
• DISTRUBANCES OF
• EXTRACELLULAR FLUID VOLUME
• ELECTROLYTE HOMEOSTASIS
• ACID-BASE BALANCE
• ACCUMULATION OF NITROGENOUS WASTE PRODUCTS
• ARF IS OFTEN REVERSIBLE
• ARF INCREASES MORBIDITY AND MORTALITY

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ACUTE RENAL FAILURE

• PRERENAL PHYSIOLOGICAL RESPONSE TO RENAL
  HYPOPERFUSION IN WHICH INTEGRITY OF RENAL
  PARENCHYMA IS PRESERVED
• INTRINSIC RENAL CAUSED BY DISEASES OF RENAL
  PARENCHYMA
• POSTRENAL ACUTE OBSTRUCTION OF URINARY TRACT

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CAUSES OF PRERENAL ARF

• INTRAVASCULAR VOLUME DEPLETION
• HEMORRHAGE, GASTROINTESTINAL, RENAL, SKIN AND
  MUCOUS MEMBRANE, THIRD SPACE LOSSES
• DECREASED CARDIAC OUTPUT
• DISEASES OF MYOCARDIUM, PERICARDIUM, VALVES ETC.
• SYSTEMIC VASODILATION
• DRUGS, SEPSIS, LIVER FAILURE, ANAPHYLAXIS
• IMPAIRED RENAL AUTOREGULATION
• ACEI, ATRA, NSAID

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CAUSES OF INTRINSIC RENAL ARF

• SEVERE RENAL HYPOPERFUSION (SIRS)
• TOXINS
• EXOGENOUS (RADIOCONTRAST, NEFROTOXIC ANTIBIOTICS,
  ANTICANCER AGENTS )
• ENDOGENOUS (RHABDOMYOLYSIS, HEMOLYSIS,
  TUMORLYSIS, HYPERCALCEMIA, LIGHT Ig CHAINS)
• DISEASES OF LARGE RENAL VESSELS
• ATHEROEMBOLISM, THROMBOSIS OF RENAL ARTERY AND
  VEIN
• DISEASES OF SMALL VESSELS AND GLOMERULI
• GLOMERULONEPHRITIS AND VASCULITIS, TTP-HUS,
  MALIGNANT HYPERTENSION
• ACUTE DISEASES OF THE TUBULOINTERSTITIUM
• ALLERGIC INTERSTICIAL NEPHRITIS, ACUTE BILATERAL
  PYELONEPHRITIS

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CAUSES OF POSTRENAL ARF

• BILATERAL OBSTRUCTION OF URETHERS
• OBSTRUCTION OF BLADDER NECK
• DISEASES OF PROSTATE GLAND
• OBSTRUCTION OF URETHRA

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DIFFERENTIAL DIAGNOSIS OF ARF

• IS THE RENAL FAILURE ACUTE, ACUTE ON CHRONIC OR
  CHRONIC?
• IS THERE RENAL TRACT OBSTRUCTION?
• IS THERE EVIDENCE OF TRUE HYPOVOLEMIA OR REDUCED
  EFFECTIVE ARTERIAL BLOOD VOLUME?
• HAS THERE BEEN A MAJOR VASCULAR OCCLUSION?
• IS THERE EVIDENCE OF PARENCHYMAL RENAL DISEASE
  OTHER THAN ATN?

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DIFFERENTIAL DIAGNOSIS OF ARF

• IS THE RENAL FAILURE ACUTE, ACUTE ON CHRONIC OR
  CHRONIC?
• ARF
• RECENT INCREASE OF BUN AND SERUM CREATININ
• CLINICAL AND HISTORY DATA CONSISTENT WITH ARF
• CRF
• PREVIOUSLY RECORDED ALTERED RENAL PARAMETRES
• HISTORY CONSISTENT WITH POSSIBLE CHRONIC KIDNEY
  DISEASE (DM, HT, AMYLOIDOSIS, NSAID)
• SEVERE ANEMIA, HYPERPHOSPHATEMIA, HYPOCALCEMIA
• ULTRASONOGRAPHY SMALL, SHRUNKEN OR POLYCYSTIC
  KIDNEYS

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DIFFERENTIAL DIAGNOSIS OF ARF

• IS THERE URINARY TRACT OBSTRUCTION?
• CLINICAL POINTS
• SUPRAPUBIC PAIN, PALPABLE BLADDER DISTENTION
• HISTORY OF PROSTATIC DISEASE (NOCTURIA, FREQUENY,
  HESITANCY)
• COLICKY PAIN WITH IRADIATION TO THE GROIN
• HISTORY OF MALIGNANCY IN PELVIS
• HISTORY OF NEUROGENIC BLADDER
• IMAGING
• ULTRASOUND, CT, MRI, IVU

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DIFFERENTIAL DIAGNOSIS OF ARF

• IS THERE EVIDENCE OF TRUE HYPOVOLEMIA OR REDUCED
  EFFECTIVE ARTERIAL BLOOD VOLUME?
• HISTORY
• BLEEDING, LOSS OF SOLUTES, LOW FLUID INTAKE
• HEART OR LIVER FAILURE
• NSAID, ACEI, ATRA
• SIGNS
• ORTOSTATIC HYPOTENSION, TACHYCARDIA, DRY MUCOUS
  MEMBRANES, LOW JUGULAR VENOUS PRESSURE, OLIGURIA,
  SEPSIS/SIRS
• LABORATORY AND URINARY FINDINGS
• HEMOCONCENTRATION, ?UREA/KREATININ, ?SPEC.
  GRAVITY OF URINE, ? U-Na
• INVASIVE MONITORING
• CENTRAL VENOUS PRESSURE, SWAN-GANZ CATHETR

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DIFFERENTIAL DIAGNOSIS OF ARF

• HAS THERE BEEN A MAJOR VASCULAR OCCLUSION?
• ATHEROEMBOLISM
• RECENT INSTRUMENTATION IN AORTA, AGE OVER 50,
  SEVERE ATHEROSCLEROSIS, WARFARIN
• PURPURA, LIVEDO RETIKULARIS
• EOSINOPHILIA, HYPOCOMPLEMENTEMIA
• RENAL BIOPSY
• TROMBOSIS OF RENAL ARTERY
• HISTORY OF ATRIAL FIBRILLATION, RECENT MI
• NAUSEA, ABDOMINAL PAIN, FLANK PAIN
• ANGIOGRAPHY, AG-CT, MRI
• TROMBOSIS OF RENAL VEIN
• NEPHROTIC SYNDROME, PULMONARY EMBOLISM
• AG, AG-CT, MRI, DOPPLER US

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DIFFERENTIAL DIAGNOSIS OF ARF

• IS THERE EVIDENCE OF PARENCHYMAL RENAL DISEASE
  OTHER THAN ATN?
• HISTORY AND PHYSICAL EXAM
• ARTHRALGIAS
• SKIN CHANGES
• PULMONARY AND ETN DISORDER
• MALIGNANT HYPERTENSION
• URINANALYSIS
• ACTIVE URINE SEDIMENT (PRUgt1g/d, ERY-U)
• LAB
• SIGNS OF MICROANGIOPATIC HEMOLYSIS
• IMUNOLOGY (ANCA, ANA, C3, C4, ANTI-GBM, APLA)
• RENAL BIOPSY

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ACUTE TUBULAR NECROSIS (ATN)

• ETIOLOGY
• ISCHEMIA
• TOXINS
• SIRS/SEPSIS
• PATOPHYSIOLOGY
• VACUOLATION, LOSS OF BRUSH BORDER,
  APOPTOSIS/NECROSIS OF TUBULÁR CELLS
• INTRARENAL VASOCONSTRICTION, IMPAIRED RENAL
  AUTOREGULATION
• INTRATUBULAR OBSTRUCTION
• INFILTRATION BY NEUTROPHILS AND MACROPHAGES
• PROGNOSIS
• UNCOMPLICATED ATN REVERSES IN 2-3 WEEKS
• CORTICAL NECROSIS IS IRREVERSIBLE

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ACUTE TUBULAR NECROSIS (ATN)

• DIFF.DG. OF PRERENAL AZOTEMIA AND ATN
• PRERENAL AZOTEMIA
• ADEQUATE KIDNEY RESPONSE TO VOLUME DEPLETION
• ? URINE OSMOLALITY (U-OSMgt500 mOsm/kg)
• ? SPECIFIC GRAVITY (gt1,018)
• LOW URINARY SODIUM (U-Nalt10 mmol/l, FeNa lt1)
• RAPID RESTORATION AFTER VOLUMEXPANSION
• ATN
• DISTURBED CONCENTRATING AND VOLUMEREGULATORY
  KIDNEY FUNCTION
• ? URINE OSMOLALITY (U-OSMlt250 mOsm/kg)
• ? SPECIFIC GRAVITY (lt 1,012)
• HIGH URINARY SODIUM (U-Na gt 20 mmol/l, FeNa gt 2)

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NEFROTOXIC AGENTS

• HEME PIGMENTS
• MYOGLOBIN RHABDOMYOLYSIS
• MUSCLE TRAUMA, ETHANOL, SEIZURES, LIMB ISCHEMIA,
  STATINS, FIBRÁTES
• ? CK, MYOGLOBIN IN PLASMA
• HEMOGLOBIN HEMOLYSIS
• INKOMPATIBILE TRANSFUSION, AIHA, SNAKE VENOM,
  MALÁRIA, G6PDH DEFICIENCY, PNH
• RADIOCONTRAST
• NEPHROTOXIC DRUGS
• NSAID, ACEI, ATRA
• AMINOGLYKOSIDS, AMFOTERICIN B, PENTAMIDIN,
  ACYCLOVIR
• CYCLOSPORINE, TAKROLIMUS
• CISPLATINE, IFOSFAMIDE
• ETHYLENGLYKOL, HEAVY METALS, HERBAL REMEDIES

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ACUTE RENAL FAILURE COMPLICATIONS

• HYPERVOLEMIA
• HYPERKALEMIA
• METABOLIC ACIDOSIS
• UREMIA
• HYPERURICEMIA
• HYPOCALCEMIA, HYPERPHOSFATEMIA
• RECOVERY PHASE OF ARF
• POLYURUIA
• HYPERNATREMIA, HYPOKALEMIA, HYPOMAGNESEMIA,
  HYPOPHOSFATEMIA

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ACUTE RENAL FAILURE MANAGEMENT

• PRERENAL ARF ? RESTORATION OF RENAL PERFUSION
• REPLACEMENT OF FLUID LOSSES (CRYSTALOIDS,
  COLLOIDS)
• MANAGEMENT OF CIRCULATORY FAILURE (INVASIVE
  HEMODYNAMIC MONITORING, TREATMENT OF HEART
  FAILURE, IONOTROPES, VASOACTIVE DRUGS)
• POSTRENAL ARF ? RELIEVE OBSTRUCTION
• MULTIDISCIPLINARY APPROACH (RADIOLOGIST,
  UROLOGIST, NEPROLOGIST)
• URINARY BLADDER CATHETER
• NEPHROSTOMY

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ACUTE RENAL FAILURE MANAGEMENT

• INTRARENAL ARF
• PREVENTION
• OPTIMAL HYDRATION OF PATIENTS AT RISK
• MONITORING OF LEVELS OF AMINOGLYCOSIDES AND
  CYKLOSPORINE
• N-ACETYLCYSTEINE?
• CAVE ACEI, NSAID, DIURETICS
• SUPPORTIVE TREATMENT
• ADRESSING COMPLICATIONS (ACIDOSIS, ELECTROLYTE
  ABNORMALITIES, HYPERVOLEMIA)
• DIALYSIS (OR HEMOFILTRATION)
• TREATMENT OF SPECIFIC CAUSES OF ARF
• TTP-HUS, RPGN, ATIN

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ACUTE RENAL FAILURE INDICATIONS OF DIALYSIS

• UREMIA
• HYPERKALEMIA
• HYPERVOLEMIA
• SEVERE ACIDOSIS