ACUTE RENAL FAILURE DEFINITION ABRUPT DECREASE IN RENAL
ACUTE RENAL FAILURE
DEFINITION ABRUPT DECREASE IN RENAL FUNCTION RESULTING IN THE ACCUMULATION OF NITROGENOUS COMPOUNDS SUCH AS UREA AND CREATININE
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Acute vs Chronic Renal Failure l History » Known Chronic » Recent Toxic Exposure » Recent Hypoxic Insult » Recent Trauma » Known Diseases Associated with ARF » Prev. Abnormal Lab Results Suggesting Chronic
Acute vs Chronic Renal Failure Rapidly Rising Creatinine = Acute l Kidney Size l » Small = Chronic l Renal Ultrasound » Increased Echogenicity = Chronic l Urine Flow Rate » Oliguric or Anuric usually = Acute
ACUTE RENAL FAILURE CLASSIFICATION BY URINE VOLUME OLIGURIC: <400 CC/ 24 Hrs NON-OLIGURIC: >500 CC/24 Hrs ANURIC <50 CC/24 Hrs
ETIOLOGY OF ACUTE RENAL FAILURE l PRE-RENAL 55 -60% l POST RENAL <5% l RENAL 35 -40%
PRE-RENAL ACUTE RENAL FAILURE l MOST COMMON CAUSE OF ARF l RESULTS FROM DECREASED RENAL PERFUSION l TREATMENT OF THE CAUSE RESTORES RENAL FUNCTION TUBULAR FUNCTION INTACT * l PROLONGED PRE-RENAL FAILURE MAY LEAD TO ATN
CAUSES OF PRE-RENAL AZOTEMIA Intravascular volume depletion l Decreased cardiac output l Systemic vasodilation l » Antihypertensives » Sepsis Renal vasoconstriction l Drugs impairing autoregulation l » Ace inhibitors NSAID
MECHANISMIS OF PRE RENAL ARF
POST-RENAL ACUTE RENAL FAILURE ACCOUNTS FOR 2 -15% OF ALL ARF l OBSTRUCTION TO URINE FLOW l » INCREASED TUBULAR PRESSURE » VASOCONSTRICTION – DECREASED RENAL BLOOD FLOW l MUST BE BILATERAL TO RESULT IN ARF » UNLESS : SINGLE KIDNEY OR PRIOR CHRONIC RENAL FAILURE
POST RENAL ACUTE RENAL FAILURE SUSPECT OBSTRUCTION IN ANURIA l ETIOLOGY MAY BE AGE DEPENDENT l » YOUNG = CONGENITAL ABNORMALITY » OLDER MALE = PROSTATIC ENLARGEMENT l ARF MOST OFTEN ASSOCIATED WITH LESIONS IN: » BLADDER, PROSTATE OR URETHRA
RENAL-ACUTE RENAL FAILURE l VASCULAR DISEASE » VASCULITIS (SLE, POLYARTERITIS ETC. ) » SCLERODERMA » THROMBOEMBOLIC DISEASE » MALIGNANT HYPERTENSION
RENAL--ACUTE RENAL FAILURE l GLOMERULAR DISEASE » ACUTE GLOMERULONEPHRITIS – POST INFECTIOUS GN – CRESCENTIC GN l ANCA POSITIVE DISEASES – GOODPASTURE’S DIS. l ANTI- GLOMERULAR BASEMENT ANTIBODY
RBC CAST
ACUTE INTERSTITIAL NEPHRITIS DRUG INDUCED l l l PENICILLINS SULFONAMIDES CEPHALOSPORIN RIFAMPIN ( 2 ND TIME) QUINOLONES l l l NSAID (FENOPROFEN) ALLOPURINOL PHENYTOIN THIAZIDES FUROSEMIDE CIMETIDINE
Acute Interstitial Nephritis l Fever l Rash l Eosinophilia l Pyuria l Eosinophiluria l WBC Casts
WBC Cast
RENAL --ACUTE RENAL FAILURE l ACUTE TUBULAR NECROSIS » ISCHEMIC INJURY » TOXIC INJURY – ENDOGENOUS TOXINS l HEMOGLOBINURIA l MYOBLOBINURIA (RHABDOMYOLYSIS) l ENDOTOXEMIA
RENAL-- ACUTE RENAL FAILURE l ACUTE TUBULAR NECROSIS » EXOGENOUS TOXINS – AMINOGLYCOSIDES – RADIOGRAPHIC CONTRAST – HEAVY METAL COMPOUNDS – ETHYLENE GLYCOL – METHANOL – CARBON TETRACHLORIDE – CIS PLATIN
HIGH RISK SETTINGS FOR ATN CLINICAL SETTING FREQUENCY l l l l GEN. MED. --SURG. INTENSIVE CARE OPEN HEART SURG AMINOGLYCOSIDE BURNS RHABDOMYOLYSIS CIS-PLATIN 3 -5% 5 -20% 10 -30% 20 -60% 20 -30% 15 -25%
ATN SEDIMENT
DIAGNOSTIC APPROACH TO ARF HISTORY l PHYSICAL EXAMINATION l ASSMENT OF URINE VOLUME l URINE ANALYSIS l BLOOD CHEMISTRY l BLOOD AND URINE INDICES l RADIOLOGIC STUDIES l
Treatment of ARF
Hyperkalemia Never occurs in the absence of renal excretory problem l Pseudohyperkalemia l » Leukocytosis » Thrombocytosis » Prolonged Application of Tourniquet
Hyperkalemia Significance of urine output l Role of increased catabolism or tissue breakdown l Factors affecting shift of Potassium out of cells l Etiololgy of the renal failure l
Treatment of Hyperkalemia Urgency l Role of the EKG in making the decision l Clinical setting in which it occurs l » Acute renal failure » Chronic renal failure
Table 5 -3. Treatment of hyperkalemia Medication Mechanism of action Dosage Calcium gluconate Antagonism of membrane Insulin and Glucose Increased K+entry into the cells Insulin, 10 U IV bolus followed by 0. 5 m. U/kg of body weight per minute in 50 ml of 20% glucose Sodium bicarbonate Increased K+entry into the cells 44 -50 m. Eq IV over 5 min; can be repeated within 30 min Albuterol Increased K+entry into the cells Peak effect 10 -30 ml of 10% solution IV over 2 min -5 min 30 -60 min 20 mg in the nebulized form 30 -60 min 2 -4 hr Kayexalate Removal of the excess K+ 20 g of resin with 100 ml of 20% sorbitol; can be repeated every 4 -6 hr Hemodialysis Removal of the excess K+ Dialysis bath K+ concentration variable 30 -60 min
INDICATIONS FOR DIALYSIS IN ACUTE RENAL FAILURE UREMIC SYMPTOMS ~ nausea ~ neurologic l SEVERE FLUID OVERLOAD l REFRACTORY ELECTROLYTE DISORDERS ~hyperkalemia l SEVERE REFRACTORY ACIDOSIS l
INDICATIONS FOR DIALYSIS IN ACUTE RENAL FAILURE PERICARDITIS l NEUROPATHY l MENTAL STATUS CHANGE l SEIZURES l BLEEDING l TOXINS----ETHYLENE GLYCOL, l METHANOL l PROPHYLACTIC ~recent studies fail to document benefit
MORTALITY ASSOCIATED WITH SETTING OF ATN OVERALL MORTALITY l POST TRAUMATIC l MEDICAL CAUSE l SURGICAL CAUSE l NON-OLIGURIC l 40 -60% 70 -90% 15 -40% 40 -80% 26% * 50% *
CAUSES OF DEATH IN ATN
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