Acute renal failure Prolonged reversible abrupt loss of
Acute renal failure Prolonged, reversible abrupt loss of renal function Dr. Jumana Albaramki
Types of ARF n RIFLE classification based on Cr, urine output. (risk, injury, renal failure, renal loss, ESRD) AKIN n prerenal, postrenal n Oliguric (<. 5 ml/kg/h or <1 ml/kg/h) , nonoliguric n
Prerenal causes n n 1. intravascular volume depletion: bleeding, GIT losses, third spacing 2. low cardiac output: CHF 3. Sepsis Treatment: fluid management and restoration of effective circulatory volume
Renal causes n 1. ATN, acute cortical necrosis from drugs, ischemic vasoconstrictive injury n 2. Glomerulonephritis: PSGN, SLE, HSP n 3. HUS: Most common cause n 4. Acute interstital nephritis
n 5. drug induced ARF: n NSAID cause ischemic vasoconstriction, decrease GFR, ATN AG: direct tubular injury ACEI: decrease renal blood flow CNI: decrease GFR, HTN n n n
n n 6. pigment nephropathy: rhabdomyolysis myoglobinuria, result trauma, status epilepticus, hereditary tx with fluids, alkali, diuretics n Tumor lysis syndrome: high uric acid, phosphate, low calcium. Tx allopurinol, alkalinazation of urine ph 7 n 8. renal artery, vein thrombosis
Post renal ARF Obstruction at level of ureter till urethra n Elevated tubular pressure decrease GFR n Duration of obstruction affects recovery n Congenital (PUJ, PUV), acquired (stones) n Post obstructive diuresis: dilute urine with large Na losses, reduced excretion of H, K n
Important points in history : n Previous GE, previous throat infection n Fever, rash, joint pain n Urinary symptoms n Drug history n FH of renal disease n O/E: state of hydration, hemodynamic status n
Investigations Elevated urea, creatinine, spot Na n Fe. Na=(Una X Pcr )/( Pna XUcr) X 100% n Fe. Na < 1% in prerenal, 2 -3% renal n Fe. Na unreliable in diuretics, neonate n High in bartter, CRD. n FBC: anemia usualy chronic n
n Blood smear: schistocytes of HUS n Electrolytes: high K, acidosis, CK n Complements, ANA, anti. DNAs, ANCA, n Imaging: U/S , Doppler (kidney size, echogenecity n Renal biobsy
Role of U/S in renal failure ultrasound Dilated PCS Large, echogenic kidneys Obstruction ARF Small kidneys or cysts CRF
n Urine analysis for proteinuria (glomerular, tubular) n Urine sediment: RBC, WBC casts, crystals, myoglobin, red brown granular, tubular epithelial casts in ischemic, nephrotoxic ATN, eosinophiluria n New kidney markers of injury: KIM 1, cystatin C
Management n Monitoring: weight, input/output chart, B. P n Fluids: bolus of crystalloid, furosemide as indicated by hydration Fluid restriction to U. O. P and insensible losses at 400/m 2 ? ? Role of renal dose dopamine in reversing oliguria ? ? Role of lasix in reversing oliguria Conservative: Recovery phase: polyuria n n
Hyponatremia: dilutional, fluid restriction n Na < 120, Tx with hypertonic saline= (125 measures) X. 6 X wt over 2 -4 h. n n High PO 4, low Ca: diet restriction, phosphate binders n Acidosis: correct Ca before, give I. V HCO 3=. 5 X wt x (22 -measure) over 1 -2 h
HTN: fluid overload or vasoconstriction due hypovolemia n Tx: diuretics, dialysis, nifedipine n Hyperkalemia: low potassium diet, Ca gluconate, insulin and glucose, sodium biocarbonate, ventolin, oral resins n n Nutrition: fluid restriction, catabolism result in high urea, K, need sufficient calories
Indications for renal replacement therapy Persistent hyperkalemia n Diuretic resistant volume overload and associated hypertension and heart failure n Refractory acidosis n Severe uremia with risk of encephalopathy and /or pericarditis n
Choice of renal replacemnet thearpy n n n 1. acute peritoneal dialysis: Peritoneal membrane is a semipermeable membrane with a large surface area Needs tenkoff catheter (rigid, permnant ) Use diffusion and convection by ultrafilteration PD fluids has electrolytes, glucose ( 1. 5 %, 4. 25 % ), acid buffer of biocarbonate
Peritoneal dialysis Volume of 10 -50 ml/kg n Dwell time of 20 -60 min n Used for young infants, avoids sudden shifts of fluid and metabolites, miminal fluid and dietary restrictions n Complications : Infection : exit site, tunnel, peritonitis n Blockage n
Dialysis Solution (Dialysate) PD Solution §Sodium - 132 §Chloride = 98 §Lactate = 40 §Calcium = 1. 2 1. 75 §Mg = o. 5 DIFFUSION OF WASTE PRODUCTS • The movement of solid particles (across a semi permeable membrane) from an area of high concentration, to an area where the concentration is lower in order to achieve eventual equilibrium • Small amt of solute removal by convection
Peritoneal Dialysis - Water Removal by Osmosis “The movement of water through a membrane from a higher to a lower water concentration area. ” This is achieved by adding glucose to the dialysis solution, however alternative osmotic agents are the future of PD.
Peritoneal Dialysis- FILL
Peritoneal Dialysis - DWELL
Peritoneal Dialysis - DRAIN
Acute intermittent hemodialysis Needs vascular acsess and anticoagulation n Rapid correction so contraindicated in hemodynamic instability n Complication : hypotension, dialysis disequilibrium due to rapid correction of urea n Requires greater fluid restriction n CVVH n
TIN n The absence of HTN, significant proteinuria, RBC casts, exposure to drugs, sterile pyuria, good urine output, evidence of tubular dysfunction favor TIN n Present nonspecific with fever, flank pain, skin rash, arthralgia n Leucocytosis, eosinophilia, high ESR, ARF Hematuria, non-nephrotic proteinuria n
n Kidney U/S: enlarged echogenic kidneys n Causes: drugs(NSAIDS, AB), infections n Kidney Bx: interstitial cellular infiltrate, definite Dx. n Treatment: stop drug, treat infection, steriods
Interstitial Nephritis
Eosinophils in acute interstitial nephritis n
HUS Acute haemolytic anaemia Reduced GFR Thrombocytopaenia
n Most commom cause of ARF n Triad: MAH, ARF, thrombocytopenia n Pathology: endothelial cell injury microthrombi , ischemic injury to multiple organs n Kidney : glomerular, arterial thrombotic microangiopathy , cortical necrosis
Classification of HUS n Infectious (Stx) ¨ E coli 0157: H 7 ¨ Shigella dysenteriae type I (D+ HUS) n Hereditary ¨ Factor H deficiency, VWF proteinase def, ADAMTS-13 n Secondary ¨ Pregnancy ¨ Malignancy n Medication ¨ CNIs
Diarrhae + HUS n n n D+HUS: follows STEC, shigella Transmitted undercooked hamburgers, milk, person to person O 157: H 7 E. coli most common serotype 5 -15% of kids infected STEC develop HUS Risk of HUS increase with age <5 y, WBC >13, 000/mm 3, antimotiliy drugs (retention of toxin Antibiotic can increase risk? ? Release toxin
Clinical Manifestations n Diarrhea 3 -7 d after exposure to STEC, mostly bloody n Pallor, oliguria 4 -7 d post diarrhoea GIT: severe colitis, transmural n necrosis, perforation, stricture, rectal prolapse n n Hepatitis, jaundice 35%
Progression of E coli O 157: H 7 infections in children
n Pancreatitis n Glucose intolerance, IDDM n CNS: 20% seizures, irritability, confusion n Mycardium ischemia rare, rhabdomyolysis n HTN, renal cortical necrosis, 50% are anuric, 75% needs dialysis
Investigations FBC, showes anemia and low platlets. n LDH high, blood film shows schizocytes, fragmented RBC n High urea and creatinine n Elevated liver enzymes 40 % n hematuria, proteinuria n
Microangiopathic hemolytic anemia
Management Transfusion if severe hemolysis, slowly 4 h n Monitor fluid and electrolyte status n Platlet if bleeding, can accelerate microthrombi formation n RRT if ARF n Synsorb Pk doesn’t decrease progression to HUS n
Outcome n n Duration of oliguria is best predictor of outcome, worse if more than one week 30% had adverse renal outcomes, HTN, renal impairment 5 -10% develop ESRD RRT during acute phase, if recover risk of future renal disease
RPGN 1. PSGN n 2. MPGN n 3. Lupus nephritis n 4. Wegner, good pasture n Treatment with high dose pulse steriods n
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