ACUTE RENAL FAILURE INTERN EMERGENCY LECTURE SERIES 2005
Dec 14, 2015
ABRUPT DECREASE IN RENAL FUNCTION RESULTING IN THE
ACCUMULATION OF NITROGENOUS COMPOUNDS
SUCH AS UREA AND CREATININE
DEFINITION
Acute vs Chronic Renal Failure
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 Kidney Size
» Small = Chronic Renal Ultrasound
» Increased Echogenicity = Chronic 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
PRE-RENAL ACUTE RENAL FAILURE
MOST COMMON CAUSE OF ARF
RESULTS FROM DECREASED RENAL PERFUSION
TREATMENT OF THE CAUSE RESTORES RENAL FUNCTION TUBULAR FUNCTION INTACT *
PROLONGED PRE-RENAL FAILURE MAY LEAD TO ATN
CAUSES OF PRE-RENAL AZOTEMIA
Intravascular volume depletion Decreased cardiac output Systemic vasodilation
» Antihypertensives» Sepsis
Renal vasoconstriction Drugs impairing autoregulation
» Ace inhibitors NSAID
POST-RENAL ACUTE RENAL FAILURE
ACCOUNTS FOR 2-15% OF ALL ARF OBSTRUCTION TO URINE FLOW
» INCREASED TUBULAR PRESSURE» VASOCONSTRICTION
– DECREASED RENAL BLOOD FLOW
MUST BE BILATERAL TO RESULT IN ARF» UNLESS : SINGLE KIDNEY OR PRIOR
CHRONIC RENAL FAILURE
POST RENAL ACUTE RENAL FAILURE
SUSPECT OBSTRUCTION IN ANURIA ETIOLOGY MAY BE AGE DEPENDENT
» YOUNG = CONGENITAL ABNORMALITY» OLDER MALE = PROSTATIC
ENLARGEMENT ARF MOST OFTEN ASSOCIATED
WITH LESIONS IN:» BLADDER, PROSTATE OR URETHRA
RENAL-ACUTE RENAL FAILURE
VASCULAR DISEASE
» VASCULITIS (SLE, POLYARTERITIS ETC.)
» SCLERODERMA
» THROMBOEMBOLIC DISEASE
» MALIGNANT HYPERTENSION
RENAL--ACUTE RENAL FAILURE
GLOMERULAR DISEASE» ACUTE GLOMERULONEPHRITIS
–POST INFECTIOUS GN–CRESCENTIC GN
ANCA POSITIVE DISEASES
–GOODPASTURE’S DIS. ANTI- GLOMERULAR BASEMENT
ANTIBODY
ACUTE INTERSTITIAL NEPHRITISDRUG INDUCED
PENICILLINS SULFONAMIDES CEPHALOSPORIN RIFAMPIN ( 2ND
TIME) QUINOLONES
NSAID (FENOPROFEN)
ALLOPURINOL PHENYTOIN THIAZIDES FUROSEMIDE CIMETIDINE
RENAL --ACUTE RENAL FAILURE
ACUTE TUBULAR NECROSIS» ISCHEMIC INJURY» TOXIC INJURY
– ENDOGENOUS TOXINS
HEMOGLOBINURIA
MYOBLOBINURIA (RHABDOMYOLYSIS)
ENDOTOXEMIA
RENAL-- ACUTE RENAL FAILURE
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
GEN.MED. --SURG. 3-5% INTENSIVE CARE 5-25% OPEN HEART SURG 5-20% AMINOGLYCOSIDE 10-30% BURNS 20-60% RHABDOMYOLYSIS 20-30% CIS-PLATIN 15-25%
DIAGNOSTIC APPROACH TO ARF
HISTORY PHYSICAL EXAMINATION ASSMENT OF URINE VOLUME URINE ANALYSIS BLOOD CHEMISTRY BLOOD AND URINE INDICES RADIOLOGIC STUDIES
Hyperkalemia
Never occurs in the absence of renal excretory problem
Pseudohyperkalemia» Leukocytosis» Thrombocytosis» Prolonged Application of Tourniquet
Hyperkalemia
Significance of urine output Role of increased catabolism or tissue
breakdown Factors affecting shift of Potassium out
of cells Etiololgy of the renal failure
Treatment of Hyperkalemia
Urgency Role of the EKG in making the decision 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
Calcium Antagonism of 10-30 ml of 10% solution IV -5 min gluconate membrane over 2 min
Insulin and Increased K+entry Insulin, 10 U IV bolus 30-60 min Glucose into the cells followed by 0.5 mU/kg of
body weight per minute in 50 ml of 20% glucose
Sodium Increased K+entry 44-50 mEq IV over 5 min; 30-60 min bicarbonate into the cells can be repeated within 30
minAlbuterol Increased K+entry
into the cells 20 mg in the nebulized form 30-60 min
Kayexalate Removal of the 20 g of resin with 100 ml of 2-4 hr excess K+ 20% sorbitol; can be
repeated every 4-6 hr
Hemodialysis Removal of the Dialysis bath K+ concentration 30-60 min excess K+ variable
INDICATIONS FOR DIALYSIS IN ACUTE RENAL FAILURE
UREMIC SYMPTOMS
~ nausea
~ neurologic SEVERE FLUID OVERLOAD REFRACTORY ELECTROLYTE
DISORDERS
~hyperkalemia SEVERE REFRACTORY ACIDOSIS
INDICATIONS FOR DIALYSIS IN ACUTE RENAL FAILURE
PERICARDITIS NEUROPATHY MENTAL STATUS CHANGE SEIZURES BLEEDING TOXINS----ETHYLENE GLYCOL,
METHANOL PROPHYLACTIC
~recent studies fail to document benefit
MORTALITY ASSOCIATED WITH SETTING OF ATN
OVERALL MORTALITY 40-60% POST TRAUMATIC 70-90% MEDICAL CAUSE 15-40% SURGICAL CAUSE 40-80% NON-OLIGURIC 26% * OLIGURIC 50% *