Acute Renal failure

Dr. Abhijeet DeshmukhDept. of Pediatrics

Pushpagiri Medical College & RCTiruvalla, Kerala

Definition

• A clinical syndrome in which a sudden deterioration in renal function results in the inability of the kidneys to maintain fluid and electrolyte homeostasis.

• Also k/a Acute renal insufficiency• 2-3% of children admitted to pediatric tertiary

care centres• 8% of infants in neonatal ICU.

pRIFLE criteria

PathogenesisPRERENAL INTRINSIC RENAL POSTRENAL

  Dehydration Glomerulonephritis Posterior urethral valves

  Hemorrhage•Postinfectious•poststreptococcal

Ureteropelvic junction obstruction

  Sepsis •Lupus erythematosus Ureterovesicular junction 

  Hypoalbuminemia •Henoch-Schönlein purpura obstruction

  Cardiac failure •Membranoproliferative Ureterocele

•Anti-glomerular basement membrane

Tumor

Urolithiasis

Hemolytic-uremic syndrome Hemorrhagic cystitis

Acute tubular necrosis Neurogenic bladder

Cortical necrosis

Renal vein thrombosis

Rhabdomyolysis

Acute interstitial nephritis

Tumor infiltration

Tumor lysis syndrome

Lab Findings

Anemia : Dilutional or hemolytic eg. SLE, renal vein thrombosis, HUS

Leukopenia : SLE, sepsisThrombocytopenia :SLE, renal vein

thrombosis, sepsis, HUSHyponatremia : dilutional Metabolic acidosisElevated BUN, creatinine, uric acid, potassium,

and phosphate (diminished renal function); and hypocalcemia (hyperphosphatemia).

• Decreased serum C3 level :

- Postinfectious glomerulonephritis, SLE, MPGN,

• Antibodies :

- Streptococcal : PSGN

- Nuclear : SLE

- Neutrophil cytoplasmic : Wegener granulomatosis, microscopic polyarteritis

- GBM :Goodpasture disease

• Sensitivity and specificity of urine Na of <20 in differentiating prerenal azotemia from acute tubular necrosis are 90% and 82%, respectively.

• Fractional excretion of sodium

= urine:plasma (U/P) ratio of sodium divided by U/P of creatinine × 100. (sensitivity and specificity of fractional excretion of

sodium of <1% in differentiating prerenal azotemia from acute tubular necrosis are 96% and 95%, respectively)

• CXR : cardiomegaly, pulmonary congestion (fluid overload) or pleural effusions.

• Renal USG :

hydronephrosis /hydroureter, Nephromegaly- s/o intrinsic renal disease.

• Renal biopsy : who do not have clearly defined prerenal or postrenal ARF

• Other biomarkers:

- changes in plasma neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C levels

- urinary changes in NGAL, interleukin-18 (IL-18), and kidney injury molecule-1 (KIM-1).

Management

• Catheterization - in newborn with suspected posterior ureteral valves & nonambulatory older children.

If there is no evidence of volume overload or cardiac failure, intravenous administration of isotonic saline, 20 mL/kg over 30 min.

hypovolemic patients generally void within 2 hr after bolus; failure points to intrinsic or postrenal ARF.

Hypotension due to sepsis - vigorous fluid resuscitation f/b continuous infusion of norepinephrine.

• Diuretic therapy : only after the adequate hydration. Mannitol (0.5 g/kg) and furosemide (2-4 mg/kg) - as a single

IV dose. [Mannitol - effective in pigment (myoglobin, hemoglobin)-induced renal failure.]

Bumetanide (0.1 mg/kg)- an alternative to furosemide.

If urine output is not improved - continuous diuretic infusion may be considered.

Consider Dopamine (2-3 µg/kg/min) in conjunction with diuretic therapy.

There is little evidence that diuretics or dopamine can prevent ARF or hasten recovery.

• Hyperkalemia• Sr K >6 mEq/L - cardiac arrhythmia, cardiac arrest, and death. • Earliest ECG change - peaked T waves f/b widening of the QRS

intervals, ST segment depression, ventricular arrhythmias, and cardiac arrest.

• Exogenous sources of K : dietary, intravenous fluids, total parenteral nutrition) should be eliminated.

• Sodium polystyrene sulfonate resin (Kayexalate) : (1 g/kg) - orally or by retention enema when Sr K>6 mEq/L

- exchanges sodium for potassium

- can take several hours to take effect. A single dose of 1 g/kg can lower the sr K level by about 1 mEq/L.

- Resin therapy may be repeated every 2 hr, the frequency being limited primarily by the risk of sodium overload.

• If Sr K >7 mEq/L : emergency measures in addition to Kayexalate.  

Calcium gluconate 10% solution : 1.0 mL/kg IV, over 3-5 min

Sodium bicarbonate :1-2 mEq/kg IV, over 5-10 min

Regular insulin : 0.1 U/kg, with glucose 50% solution, 1 mL/kg, over 1 hr

• Mild metabolic acidosis:

common in ARF - rarely requires treatment.

If severe (arterial pH < 7.15; serum bicarbonate < 8 mEq/L) or contributes to hyperkalemia it should be corrected.

• Hypocalcemia :

- Primarily treated by lowering the serum phosphorus level.

- Calcium should not be given IV except in cases of tetany, to avoid deposition of calcium salts into tissues.

- Follow a low-phosphorus diet,

• Hyponatremia 

- most commonly a dilutional

- must be corrected by fluid restriction.

- hypertonic (3%) saline - limited to symptomatic hyponatremia (seizures, lethargy) or those with a serum sodium level <120 mEq/L.

• GI bleeding  because of uremic platelet

dysfunction, increased stress, and heparin exposure in hemodialysis.

Oral or intravenous H2 blocker-Ranitidine.

• Hypertension  Common in ARF patients with acute

glomerulonephritis or HUS. Salt and water restriction, diuretics Isradipine (0.05-0.15 mg/kg/dose,

amlodipine, 0.1-0.6 mg/kg/24 hr qd or divided bid

propranolol, 0.5-8 mg/kg/24 hr divided bid or tid;

labetalol, 4-40 mg/kg/24 hr divided bid or tid severe symptomatic hypertension - continuous

infusions of sodium nitroprusside or esmolol

• Neurologic symptoms Headache, seizures, lethargy, and confusion

(encephalopathy). Potential etiologic factors - hyponatremia,

hypocalcemia, hypertension, cerebral hemorrhage, cerebral vasculitis, and the uremic state.

Diazepam - most effective in controlling seizures,

Treat the underlying cause.

• Anemia of ARF generally mild packed red blood cells if Hb < 7 g/dLSlow (4-6 hr) transfusion with packed red

blood cells (10 mL/kg) diminishes the risk of hypervolemia.

• Nutrition In most cases, sodium, potassium, and

phosphorus should be restricted. Protein – restricted & caloric intake

maximised to minimize the accumulation of nitrogenous wastes.

Critically ill patients with ARF - parenteral essential amino acids given

• Protein : enough protein for growth - limiting high protein intake. Protein needs increase on dialysis. Foods with protein include

eggs

milk

cheese

chicken

fish

red meats

beans

yogurt

cottage cheese

• Sodium. Depend on stage of their kidney disease, their age,

and sometimes other factors. Foods high in sodium include• canned foods• some frozen foods• most processed foods• some snack foods, such as chips

Potassium. Low-potassium High-potassium

- apples––cranberries––strawberries––blueberries––raspberries––pineapple––cabbage––boiled cauliflower––mustard greens

- oranges––melons––apricots––bananas––potatoes––tomatoes––sweet potatoes––cooked spinach

Health care team

• pediatrician • nephrologist • dialysis nurse • transplant coordinator • transplant surgeon • social worker • financial counselor • dietitian

Dialysis

• Indications  Volume overload with evidence of hypertension and/or

pulmonary edema refractory to diuretic therapy  Persistent hyperkalemia Severe metabolic acidosis unresponsive to medical

management Neurologic symptoms (altered mental status, seizures) Blood urea nitrogen >100-150 mg/dL (or lower if rapidly

rising) Calcium:phosphorus imbalance, with hypocalcemic

tetany

Thank You !

Referances

• Nelson Textbook of pediatrics 19 th edition• Treatment Methods for Kidney Failure in

Children (National instt. of Diabetes & Kidney disease)