ACUTE RENAL FAILURE INTERN EMERGENCY LECTURE SERIES 2005

ABRUPT DECREASE IN RENAL FUNCTION RESULTING IN THE ACCUMULATION OF NITROGENOUS COMPOUNDS SUCH AS UREA AND CREATININE DEFINITION

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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 l Rapidly Rising Creatinine = Acute l Kidney Size »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 RENAL35-40%

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 l Intravascular volume depletion l Decreased cardiac output l Systemic vasodilation »Antihypertensives »Sepsis l Renal vasoconstriction l Drugs impairing autoregulation »Ace inhibitors NSAID

MECHANISMIS OF PRE RENAL ARF

POST-RENAL ACUTE RENAL FAILURE l ACCOUNTS FOR 2-15% OF ALL ARF l OBSTRUCTION TO URINE FLOW »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 l SUSPECT OBSTRUCTION IN ANURIA l ETIOLOGY MAY BE AGE DEPENDENT »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 PENICILLINS l SULFONAMIDES l CEPHALOSPORIN l RIFAMPIN ( 2ND TIME) l QUINOLONES l NSAID (FENOPROFEN) l ALLOPURINOL l PHENYTOIN l THIAZIDES l FUROSEMIDE l CIMETIDINE

l Fever l Rash l Eosinophilia l Pyuria l Eosinophiluria l WBC Casts Acute Interstitial Nephritis

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 GEN.MED. --SURG.3-5% l INTENSIVE CARE5-25% l OPEN HEART SURG5-20% l AMINOGLYCOSIDE10-30% l BURNS20-60% l RHABDOMYOLYSIS20-30% l CIS-PLATIN15-25%

ATN SEDIMENT

DIAGNOSTIC APPROACH TO ARF l HISTORY l PHYSICAL EXAMINATION l ASSMENT OF URINE VOLUME l URINE ANALYSIS l BLOOD CHEMISTRY l BLOOD AND URINE INDICES l RADIOLOGIC STUDIES

Treatment of ARF

Hyperkalemia l Never occurs in the absence of renal excretory problem l Pseudohyperkalemia »Leukocytosis »Thrombocytosis »Prolonged Application of Tourniquet

Hyperkalemia l 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

Treatment of Hyperkalemia l Urgency l Role of the EKG in making the decision l Clinical setting in which it occurs »Acute renal failure »Chronic renal failure

Table 5-3. Treatment of hyperkalemia Medication Mechanism of action Dosage Peak effect CalciumAntagonism of ml of 10% solution IV -5 min gluconate membrane over 2 min Insulin and Increased K + entry Insulin, 10 U IV bolus min Glucose into the cells followed by 0.5 mU/kg of body weight per minute in 50 ml of 20% glucose SodiumIncreased K + entry mEq IV over 5 min; min bicarbonate into the cells can be repeated within 30 min AlbuterolIncreased K + entry into the cells 20 mg in the nebulized form min KayexalateRemoval of the 20 g of resin with 100 ml of 2-4 hr excess K + 20% sorbitol; can be repeated every 4-6 hr HemodialysisRemoval of the Dialysis bath K + concentration min excess K + variable

INDICATIONS FOR DIALYSIS IN ACUTE RENAL FAILURE l UREMIC SYMPTOMS ~ nausea ~ neurologic l SEVERE FLUID OVERLOAD l REFRACTORY ELECTROLYTE DISORDERS ~hyperkalemia l SEVERE REFRACTORY ACIDOSIS

INDICATIONS FOR DIALYSIS IN ACUTE RENAL FAILURE l PERICARDITIS l NEUROPATHY l MENTAL STATUS CHANGE l SEIZURES l BLEEDING l TOXINS---- ETHYLENE GLYCOL, METHANOL l PROPHYLACTIC ~recent studies fail to document benefit

MORTALITY ASSOCIATED WITH SETTING OF ATN l OVERALL MORTALITY 40-60% l POST TRAUMATIC70-90% l MEDICAL CAUSE15-40% l SURGICAL CAUSE40-80% l NON-OLIGURIC26% * l OLIGURIC50% *

CAUSES OF DEATH IN ATN