ACUTE RENAL FAILURE IN CHILDREN

Acute renal failure is an acute or sub-acute decline in the glomerular filtration rate and/or tubular function characterized by rapid accumulation of nitrogenous waste products, for example urea and creatinine, in the blood.

Aetiologies of Acute Renal Failure

The causes of acute renal failure divided into pre-renal, renal and post-renal groupings:

  1. Pre-renal acute renal failure: This group of diseases includes the following:
    • Diarrhoea and vomiting with severe dehydration,
    • Burns,
    • Inappropriate diuretic treatment,
    • Peritonitis,
    • Pancreatitis,
    • Heart failure, and
    • Liver disease with ascites.
  2. The renal grouping includes the following:
    • Diseases of the renal arteries and veins that include:
      • Direct trauma to renal vessels
      • Dissecting aortic aneurism
    • Intrinsic renal problems that include:
      • Glomerulonephritis
      • Acute interstitial nephritis
      • Acute tubular necrosis
      • Intratubular obstruction
    • Post-infectious glomerulonephritis:
      • Renal damage related to drugs for example methicillin, ibuprofen, and
        gentamicin
      • Following volume depletion and also as a result of toxins
      • Rhabdomyolysis
      • Uric acid nephropathy
  3. The post-renal grouping includes the following:
    • Obstruction of the collecting system:
      • Bladder outlet obstruction,
      • Bilateral ureteral obstruction,
      • Ureteral obstruction, and
      • A single kidney.

Clinical Features

  • Low or no urinary output (sometimes it may be normal)
  • Oedema
  • Heart failure
  • Hypertension
  • Hyperkalaemia
  • Acidosis
  • Rising blood urea and creatinine
  • Diagnostic work up including history and physical examination, as well as:
    • Careful review of medical records and medications (e.g., gentamicin).
    • Presence of swelling and oedema of muscles, which may indicate rhabdomyolysis
    • Abdomen or flank pain, which may indicate obstruction to urine flow or inflammation of the kidneys

Investigations

  • Full blood counts
  • Urinalysis and urine culture and sensitivity
  • Urea and electrolytes
  • Serum creatinine.
  • ECG if hyperkalaemic

Management

  • Hypovolaemic patients: Give 20ml/kg normal saline over 30 minutes – patient should pass urine in the next 2 hours. Replace fluid as completely as possible in patients who have vomiting, diarrhoea or burns.
  • Non hypovolaemic patient: Restrict fluid.
  • Do not give drugs that may further damage the kidneys, e.g., gentamicin, tetracycline, sulfonamides, NSAIDs, nitrofurantoin
  • If the blood pressure is normal or high and the patient is not dehydrated, give intravenous frusemide in a dose of 1–5mg/kg.
  • Treat the hypertension if indicated.
  • Treat hyperkalaemia, as indicated below:
    • For mild to moderate hyperkalaemia (K = 6–7mmol/L):
      • Do not give potassium containing fluids or food.
      • Give oral potassium retaining resins.
    • Severe hyperkalaemia (K >7mmol/L):
      • Give 1ml/kg 50% glucose with insulin 1 unit/5g of glucose over 30 minutes.
      • Repeat after 30–60 minutes if hyperkalaemia persists.
    • If there are ECG changes, give IV 10% calcium gluconate 1ml/kg/dose to be injected over 5–10 minutes.
  • Refer for dialysis if:
    • If hyperkalaemia is persistent.
    • Anuria is present for more than 24 hours OR oliguria for more than 48
      hours.