How are ischemic or nephrotoxic acute tubular necrosis (ATN) managed in intrarenal azotemia?

Updated: Sep 19, 2018
  • Author: Moro O Salifu, MD, MPH, FACP; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Answer

For ischemic or nephrotoxic acute tubular necrosis (ATN) due to shock (hypovolemic, cardiogenic, septic), the initial approach is to restore volume and pressure (with fluid replacement and vasopressors, respectively) and to withdraw any nephrotoxic drugs. [13] . If the patient becomes oliguric or anuric from shock, volume in the form of crystalloids should be aggressively administered as boluses (eg, 300 mL every 2 hours, rather than 150 mL every hour). Bolus infusion leads to acute intravascular volume expansion, release of atrial natriuretic peptide from the heart, increased renal blood flow, and natriuresis, all of which are favorable in recovery from ATN compared with slow intravenous hydration.

If at least 2 L of fluids has been administered in a relatively short period (approximately 12 hours) with no improvement in urine output, a trial of high-dose intravenous furosemide at 100-160 mg can be tried, prior to preparation for renal replacement. This approach, called “tank and blast” in shock, is clinically useful but almost no evidence supports it. In one small study, hemodynamic and renal support with a continuous infusion of noradrenaline (0.06-0.12 microg/kg/min) and furosemide (10-30 mg/hr) induced polyuria and reversed acute tubular necrosis to nonoliguric acute renal failure in 11 of 14 cancer patients who had severe sepsis and multiorgan dysfunction syndrome. [14] If the patient does not respond within 6 hours of this approach, dialysis or continuous renal replacement therapy should be considered as soon as possible.

If the patient responds by restoration of urine output to greater than 30 mL/h, continue on the appropriate amounts of intravenous fluids, vasopressors, and as-needed diuretics to keep the patient at the desired fluid balance (negative, positive, or match intake to output).

This approach is not indicated in nonshock patients with AKI. Nonshock patients with AKI require maintenance fluids, if needed, and avoidance of nephrotoxicity.

In both scenarios, early initiation of renal replacement therapy if azotemia sets in has a better prognosis than late initiation.


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