Acute kidney injury

N17.9

DESCRIPTION

Kidney injury may be due to a combination of factors.

Acute kidney injury (AKI) is defined as any of the following:

  • Increase in serum creatinine by ≥26.5 μmol/L within 48 hours; or
  • Increase in serum creatinine to ≥1.5 times baseline, which is known or presumed to have occurred within the prior 7 days; or
  • Urine volume <0.5 mL/kg/hour for 6 hours.

GENERAL MEASURES

A detailed history and good clinical examination is necessary to identify potentially reversible causes. Ensure volume status, perfusion and oxygenation. Monitor serum creatinine, potassium and urine output.

If radiocontrast diagnostic procedures are required, see: Diagnostic contrast agents and related substances.

Avoid any nephrotoxic medicines e.g. NSAIDs, aminoglycosides. Check all medicines for possible dose adjustments.

MEDICINE TREATMENT

Fluid overload

In patients with fluid overload where dialysis is not immediately available, a short trial of high dose furosemide in consultation with a specialist may be appropriate.

LoEIII

Acute dialysis

Discuss all cases with the referral centre.

Common indications for acute dialysis include:

  • Pulmonary oedema and anuria.
  • Intractable metabolic acidosis (pH < 7.2) and severe hyperkalaemia (>7 mmol/L).
  • Uraemic complications, e.g. pericarditis, encephalopathy and bleeding.
  • Medication overdose if due to dialysable toxin. See section 19: Exposure to poisonous substances.

Note: HIV infection is not a contra-indication for acute dialysis.

Both haemodialysis and peritoneal dialysis are acceptable modalities of therapy in the acute setting.

Peritoneal dialysis fluid is potentially infectious for HIV and viral hepatitis.

Hyperkalaemia

Serum K+ >6.5 mmol/L.

Emergency measures

  • Calcium gluconate 10%, slow IV bolus, 10 mL over 10 minutes.
    • Maximum dose: 40 mL.
  • Dextrose 50%, continuous IV infusion, 100 mL with soluble insulin, 10 units administered over 15–30 minutes.
    • Monitor blood glucose levels hourly.

AND

  • Salbutamol nebulisation, 5 mg.
    • Dilute in 4 mL of sodium chloride 0.9%.

These are short-term measures - patients should be dialysed or if this is not feasible:

  • Sodium polystyrene sulfonate, oral, 15 g with 15 mL lactulose, 6 hourly.

OR

  • Sodium polystyrene sulfonate, rectal, 30–60 g as an enema.
    • After 8 hours, wash out with phosphate enema.
    • Note: Rectal administration is less effective.

LoEIII

Glycaemic control

Close glycaemic control can reduce the incidence and severity of AKI.

See Diabetes mellitus.

Some patients do not recover kidney function and should be treated as CKD.