急性肾衰竭 Acute Renal Failure （ARF）
DEFINITIONS AND INCIDENCE • Acute renal failure (ARF) is a syndrome characterized by rapid decline in glomerular filtration rate(GFR) and retention of nitrogenous waste products such as blood urea nitrogen (BUN) and creatinine. • ARF complicates approximately 5% of hospital admissions and up to 30% of admissions to intensive care units.
CLASSIFICATION • Prerenal azotemia • Intrinsic renal azotemia • Postrenal azotemia
ETIOLOGY OF ARF Prerenal Azotemia • Intravascular Volume Depletion • Decreased Cardiac Output • Systemic Vasodilatation • Renal Vasoconstriction • Pharmacologic Agents (ACEI or NSAIDs)
ETIOLOGY OF ARF Postrenal Azotemia • Ureteric Obstruction • Bladder Neck Obstruction • Urethral Obstruction
ETIOLOGY OF ARF Intrinsic Renal Azotemia • Diseases Involving Large Renal Vessels • Diseases of Glomeruli And Microvasculature • Acute Tubule Necrosis • Diseases of the Tubulointerstitium
急性肾小管坏死 Acute Tubule Necrosis （ATN）
ETIOLOGY OF ATN • Renal Ischemia（50%） • Nrphrotoxins （35%） Exogenous Endogenous
PATHOPHYSIOLOGY OF ATN • Intrarenal Vasoconstriction • Tubular Dysfunction
Role of Hemodynamic alterations in ATN • Reduction in Total Renal Blood Flow Regional Disturbance in Renal Blood Flow and Oxygen Supply • Edothelin (ET) / NO (EDNO) • Other Endothelial Vasoconstrctors • The Tubulo-glomerular Feed Back
Role of Tubule Dysfunction in ATN Two Major TubularAbnormalities: Obstrction Backleak
Metabolic Responses of Tubule cells to Injury • ATP Depletion • Cell Swelling • Intyacellular Free Calcium↑ • IntyacellularAcidosis • Phospholipase Activation • Protease Activation • Oxidant Injury • Inflammatory Respose
Pathology
Clinical Presentation of ATN The Clinical Course of ATN： The Initiation Phase The Maintenance Phase The Recovery Phase
The Initiation Phase • GFR↓ • Lasting Hours or Days • Evidence of true Volume Depletion • Decreeced Effective Circulatory Volume • Treatment with NSAIDs or ACEI
The Maintenance Phase • GRR 5 ~ 10 ml/min • Lasting 1 ~ 2 Weeks • Oliguric ARF • high catabolism • Nonoliguric ARF • Uremic Syndrome
High Catabolic State • Daily Increase in BUN >10.1~17.9 mmol/L • Daily Increase in Serum Creatinine >176.8μmol/L • Daily Increase in Serum Potassium >1~2 mmol/L • Daily Decrease in Serum HCO 3 －>2 mmol/L
The Uremic Syndrome General Complications of ARF： Gastrointestinal Cardiovascular Respiratory Neurologic Hematologic Infectious
The Uremic Syndrome Homeostatic Disorder of water，Electrolyte and Acid-alkali Balance： Volume Overload Metabolic Acidosis Hyperkalemia Hyponatremia Hypocalcemia Hyperphosphatemia
The Recovery Phase The Period of Repair and Regeneration of Renal Tissue: Gradual Increase in Urine Output “Post-ATN” Diuresis Fall in BUN and Scr Recovery of GFR/ Tubule function
Lab Examination Blood Routine Test and Chemistry Assays: Animia, RBC ↓, Hb ↓ BUN and Scr↑ Na＋ ↓，K＋↑,Ca2＋↓，P3+ ↑ pH ↓，AG ↑，HCO3－ ↓
Lab Examination Diagnostic IndexPrerenal Renal Specific Gravity > 1.020 ~ 1.010 Osmolality(mOsm/Kg H2O) > 500 ~ 300 Urinary Na+ (mmol/L) < 10 > 20 Ucr/Scr > 40 < 20 UUN/BUN > 8 < 3 BUN/Scr > 20 < 10-15 Renal Failure Index < 1 > 1 Fractional Excretion of Na+ < 1 > 1 Urine Sediment Hyaline Brown ranular
Lab Examination • Radiologic Evaluation: Plain Abdominal film Renal Ultrasonography IVP Renal angiography • Renal Biopsy
Diagnosis Differentiation： prerenal azotemia postrenal azotemia Glomerulonephritis/Vasculitis HUS/TTP Interstitial Nephritis Renal Artery Thrombosis Renal vein thrombosis
Management of ARF (一) • Correction of Reversible causes • Prevention of additional Injury • Maintaining Fluid balance
Management of ARF (二) Maintaining Fluid balance Fluid Intake ： 500ml + The Amount of Urine in The Preceding 24 Hours
Management of ARF (三） Nutrition • Enegy Intake:147kj/d • Dietary Protein: 0.8g/kg.d • CRRT ( fluid > 5L/d)
Management of ARF (四） Hyperkalemia K+<6mmol/L Restriction of Dietary Potassium Intake K+-Binding Ion Exchange Resins K+>6mmol/L 10%Calcium Gluconate 10-20ml 5% Sodium Bicarbonate 100-200ml 20% Glucose 3ml/kg.h+Insulin 0.5U/kg.h Dialysis
Management of ARF (五） Metabolic Acidosis HCO3－< 15mmol/L : 5% Sodium Bicarbonate 100-250ml Dialysis
Management of ARF • Other Electrolyte Disorder • Infection • Hart failure • Dialysis
