Acute kidney injury
- Overview
- Theory
- Diagnosis
- Management
- Follow up
- Resources
Treatment algorithm
Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer
prerenal azotemia
The underlying cause of volume contraction or blood loss must be treated, along with restoring euvolemia and hemodynamic stability.
Crystalloid (normal saline or lactated Ringers) is sufficient in most cases for volume expansion. Colloid might be used if there is significant hypoalbuminemia.
In the US, the Food and Drug Administration (FDA) issued safety labeling changes in July 2021 for solutions containing hydroxyethyl starch (HES) stating that HES products should not be used unless adequate alternative treatment is unavailable.[92]Food and Drug Administration. Labeling changes on mortality, kidney injury, and excess bleeding with hydroxyethyl starch products. 7 Jul 2021 [internet publication]. https://www.fda.gov/vaccines-blood-biologics/safety-availability-biologics/labeling-changes-mortality-kidney-injury-and-excess-bleeding-hydroxyethyl-starch-products Solutions containing hydroxyethyl starch (HES) are associated with adverse outcomes including kidney injury and death, particularly in critically ill patients and those with sepsis.[93]Lewis SR, Pritchard MW, Evans DJ, et al. Colloids versus crystalloids for fluid resuscitation in critically ill people. Cochrane Database Syst Rev. 2018 Aug 3;8:CD000567. https://www.doi.org/10.1002/14651858.CD000567.pub7 http://www.ncbi.nlm.nih.gov/pubmed/30073665?tool=bestpractice.com [94]Zarychanski R, Abou-Setta AM, Turgeon AF, et al. Association of hydroxyethyl starch administration with mortality and acute kidney injury in critically ill patients requiring volume resuscitation: a systematic review and meta-analysis. JAMA. 2013 Feb 20;309(7):678-88. http://www.ncbi.nlm.nih.gov/pubmed/23423413?tool=bestpractice.com In view of the serious risks posed to these patient populations, the Pharmacovigilance Risk Assessment Committee of the European Medicines Agency in February 2022 recommended suspending HES solutions for infusion in Europe.[95]European Medicines Agency. PRAC recommends suspending hydroxyethyl-starch solutions for infusion from the market. 11 Feb 2022 [internet publication]. https://www.ema.europa.eu/en/news/prac-recommends-suspending-hydroxyethyl-starch-solutions-infusion-market-0
The US National Kidney Foundation states that crystalloids are preferred over colloids for most patients with acute kidney injury, and recommends that hydroxyethyl starches are avoided.[89]Moore PK, Hsu RK, Liu KD. Management of acute kidney injury: core curriculum 2018. Am J Kidney Dis. 2018 Jul;72(1):136-48. https://www.ajkd.org/article/S0272-6386(17)31141-1/fulltext http://www.ncbi.nlm.nih.gov/pubmed/29478864?tool=bestpractice.com
Evidence regarding the prevention of contrast-induced AKI is weak and often conflicting. Administration of normal saline at a dose of 1 mL/kg/hour for several hours before and after the contrast is believed to be beneficial in the prevention of contrast nephropathy.[53]Barrett BJ, Parfey PS. Clinical practice. Preventing nephropathy induced by contrast medium. N Engl J Med. 2006 Jan 26;354(4):379-86. http://www.ncbi.nlm.nih.gov/pubmed/16436769?tool=bestpractice.com However, a large study did not show benefit in patients at risk of contrast-induced nephropathy according to current guidelines.[54]Nijssen EC, Rennenberg RJ, Nelemans PJ, et al. Prophylactic hydration to protect renal function from intravascular iodinated contrast material in patients at high risk of contrast-induced nephropathy (AMACING): a prospective, randomised, phase 3, controlled, open-label, non-inferiority trial. Lancet. 2017 Apr 1;389(10076):1312-22. http://www.ncbi.nlm.nih.gov/pubmed/28233565?tool=bestpractice.com
As prerenal azotemia predisposes the kidney to injury from other means, such as contrast or nephrotoxins, care should be given to minimize exposures and dose-adjust drugs to maximize recovery potential.
Hemorrhage requires blood product replacement.
Treatment recommended for ALL patients in selected patient group
Vasopressors are recommended for severe hypotension, often with the goal of keeping mean arterial pressure (MAP) >60 mmHg. (MAP is the diastolic pressure plus one third of the pulse pressure, where the pulse pressure is the systolic pressure minus the diastolic pressure.) All vasopressors should be used only with appropriate hemodynamic monitoring in place.
The underlying cause of hypotension needs to be treated along with restoring euvolemia and hemodynamic stability.
The septic patient requires hemodynamic support with vasopressors as needed to support MAP and organ perfusion.
Management is often difficult if renal hypoperfusion results from impaired cardiac function. It requires optimizing cardiac output and volume status. Inotropes, diuretics, or renal replacement therapy may be required.
Consult a specialist for guidance on suitable vasopressor regimen.
Treatment recommended for SOME patients in selected patient group
The use of diuretics may be helpful to manage volume in patients with ineffective circulating volume and prerenal AKI. Diuretic-unresponsive volume overload is an indication to proceed to renal replacement therapy by means of dialysis or filtration.
Impaired urine production and volume expansion are commonly seen in cases of AKI.
Loop diuretics (e.g., furosemide) and metolazone may be effective in promoting diuresis, although diuretic resistance is often seen.
Patients also require sodium restriction.
It is important to remove or minimize any nephrotoxins.
Primary options
furosemide: 40-80 mg intravenously initially, increase by 20 mg/dose increments every 2 hours as necessary until clinical response
Secondary options
torsemide: 20 mg intravenously once daily initially, increase gradually according to response, maximum 200 mg/day
OR
bumetanide: 1-2 mg intravenously initially, may repeat in 2-3 hours for up to 2 doses if necessary, maximum 10 mg/day
OR
metolazone: 5-20 mg orally once daily
Treatment recommended for SOME patients in selected patient group
Nephrologist consultation is required.
Conventional hemodialysis for 4 to 6 hours is used in hemodynamically stable patients.
Other modes of renal replacement include sustained low-efficiency dialysis (SLED), extended daily dialysis (EDD), or continuous renal replacement therapy (CRRT).[96]Palevsky PM, Zhang JH, O'Connor TZ, et al; VA/NIH Acute Renal Failure Trial Network. Intensity of renal support in critically ill patients with acute kidney injury. N Engl J Med. 2008 Jul 3;359(1):7-20. https://www.nejm.org/doi/full/10.1056/NEJMoa0802639 http://www.ncbi.nlm.nih.gov/pubmed/18492867?tool=bestpractice.com Major commonly used modalities include continuous venovenous hemofiltration (CVVH), continuous venovenous hemodialysis (CVVHD), and continuous venovenous hemodiafiltration (CVVHDF).
CRRT is mostly used in hemodynamically unstable patients (e.g., patients with sepsis, or with severe congestive heart failure) or those in whom aggressive ultrafiltration within the conventional 4- to 6-hour treatment of hemodialysis would not be tolerated.
Studies have shown that intensive dialysis in critically ill patients with AKI confers no increased benefit.[96]Palevsky PM, Zhang JH, O'Connor TZ, et al; VA/NIH Acute Renal Failure Trial Network. Intensity of renal support in critically ill patients with acute kidney injury. N Engl J Med. 2008 Jul 3;359(1):7-20. https://www.nejm.org/doi/full/10.1056/NEJMoa0802639 http://www.ncbi.nlm.nih.gov/pubmed/18492867?tool=bestpractice.com [97]Tolwani AJ, Campbell RC, Stofan BS, et al. Standard versus high-dose CVVHDF for ICU-related acute renal failure. J Am Soc Nephrol. 2008 Jun;19(6):1233-8. https://jasn.asnjournals.org/content/19/6/1233.full http://www.ncbi.nlm.nih.gov/pubmed/18337480?tool=bestpractice.com [98]Bellomo R, Cass A, Cole L, et al; RENAL Replacement Therapy Study Investigators. Intensity of continuous renal-replacement therapy in critically ill patients. N Engl J Med. 2009 Oct 22;361(17):1627-38. https://www.nejm.org/doi/10.1056/NEJMoa0902413 http://www.ncbi.nlm.nih.gov/pubmed/19846848?tool=bestpractice.com [99]Chertow GM, Burdick E, Honour M, et al. Acute kidney injury, mortality, length of stay, and costs in hospitalized patients. J Am Soc Nephrol. 2005 Nov;16(11):3365-70. http://jasn.asnjournals.org/cgi/content/full/16/11/3365 http://www.ncbi.nlm.nih.gov/pubmed/16177006?tool=bestpractice.com [109]Jun M, Heerspink HJ, Ninomiya T, et al. Intensities of renal replacement therapy in acute kidney injury: a systematic review and meta-analysis. Clin J Am Soc Nephrol. 2010 Jun;5(6):956-63. http://www.ncbi.nlm.nih.gov/pubmed/20395356?tool=bestpractice.com
Early dialysis appeared to reduce mortality compared with a delayed strategy in one small single-center randomized trial of critically ill patients with AKI,[100]Zarbock A, Kellum JA, Schmidt C, et al. Effect of early vs delayed initiation of renal replacement therapy on mortality in critically ill patients with acute kidney injury: the ELAIN randomized clinical trial. JAMA. 2016 May 24-31;315(20):2190-9. https://jamanetwork.com/journals/jama/fullarticle/2522434 http://www.ncbi.nlm.nih.gov/pubmed/27209269?tool=bestpractice.com but a larger study and meta-analysis found no benefit associated with early initiation of renal replacement therapy.[101]Gaudry S, Hajage D, Schortgen F, et al. Initiation strategies for renal-replacement therapy in the intensive care unit. N Engl J Med. 2016 Jul 14;375(2):122-33. http://www.ncbi.nlm.nih.gov/pubmed/27181456?tool=bestpractice.com [102]Bhatt GC, Das RR. Early versus late initiation of renal replacement therapy in patients with acute kidney injury - a systematic review & meta-analysis of randomized controlled trials. BMC Nephrol. 2017 Feb 28;18(1):78. https://bmcnephrol.biomedcentral.com/articles/10.1186/s12882-017-0486-9 http://www.ncbi.nlm.nih.gov/pubmed/28245793?tool=bestpractice.com
intrinsic renal failure
Management of intrinsic renal failure varies according to etiology. Nephrotoxic agents should be ceased and the patient referred to a nephrologist if specific treatment, such as dialysis, management of fluids/acid-base status, severe hyperkalemia, or immunosuppression is required.
Treatment recommended for SOME patients in selected patient group
The use of diuretics in the management of AKI is primarily for volume control. Diuretic-unresponsive volume overload is an indication to proceed to renal replacement therapy by means of dialysis or filtration.
Impaired urine production and volume expansion are commonly seen in cases of AKI.
Loop diuretics (e.g., furosemide) and metolazone may be effective in promoting diuresis, although diuretic resistance is often seen.
Patients also require sodium restriction.
It is important to remove or minimize any nephrotoxins.
Primary options
furosemide: 40-80 mg intravenously initially, increase by 20 mg/dose increments every 2 hours as necessary until clinical response
Secondary options
torsemide: 20 mg intravenously once daily initially, increase gradually according to response, maximum 200 mg/day
OR
bumetanide: 1-2 mg intravenously initially, may repeat in 2-3 hours for up to 2 doses if necessary, maximum 10 mg/day
OR
metolazone: 5-20 mg orally once daily
Treatment recommended for SOME patients in selected patient group
Crystalloid (normal saline or lactated Ringers) is sufficient in most cases for volume expansion. Colloid might be used if there is significant hypoalbuminemia. In the US, the Food and Drug Administration (FDA) issued safety labeling changes in July 2021 for solutions containing hydroxyethyl starch (HES) stating that HES products should not be used unless adequate alternative treatment is unavailable.[92]Food and Drug Administration. Labeling changes on mortality, kidney injury, and excess bleeding with hydroxyethyl starch products. 7 Jul 2021 [internet publication]. https://www.fda.gov/vaccines-blood-biologics/safety-availability-biologics/labeling-changes-mortality-kidney-injury-and-excess-bleeding-hydroxyethyl-starch-products Solutions containing hydroxyethyl starch (HES) are associated with adverse outcomes including kidney injury and death, particularly in critically ill patients and those with sepsis.[93]Lewis SR, Pritchard MW, Evans DJ, et al. Colloids versus crystalloids for fluid resuscitation in critically ill people. Cochrane Database Syst Rev. 2018 Aug 3;8:CD000567. https://www.doi.org/10.1002/14651858.CD000567.pub7 http://www.ncbi.nlm.nih.gov/pubmed/30073665?tool=bestpractice.com [94]Zarychanski R, Abou-Setta AM, Turgeon AF, et al. Association of hydroxyethyl starch administration with mortality and acute kidney injury in critically ill patients requiring volume resuscitation: a systematic review and meta-analysis. JAMA. 2013 Feb 20;309(7):678-88. http://www.ncbi.nlm.nih.gov/pubmed/23423413?tool=bestpractice.com In view of the serious risks posed to these patient populations, the Pharmacovigilance Risk Assessment Committee of the European Medicines Agency in February 2022 recommended suspending HES solutions for infusion in Europe.[95]European Medicines Agency. PRAC recommends suspending hydroxyethyl-starch solutions for infusion from the market. 11 Feb 2022 [internet publication]. https://www.ema.europa.eu/en/news/prac-recommends-suspending-hydroxyethyl-starch-solutions-infusion-market-0
The US National Kidney Foundation states that crystalloids are preferred over colloids for most patients with acute kidney injury, and recommends that hydroxyethyl starches are avoided.[89]Moore PK, Hsu RK, Liu KD. Management of acute kidney injury: core curriculum 2018. Am J Kidney Dis. 2018 Jul;72(1):136-48. https://www.ajkd.org/article/S0272-6386(17)31141-1/fulltext http://www.ncbi.nlm.nih.gov/pubmed/29478864?tool=bestpractice.com
As prerenal azotemia predisposes the kidney to injury from other means, such as contrast or nephrotoxins, care should be given to minimize exposures and dose-adjust drugs to maximize recovery potential.
Treatment recommended for SOME patients in selected patient group
Nephrologist consultation recommended.
Conventional hemodialysis is used in hemodynamically stable patients.
Other modes of renal replacement include sustained low-efficiency dialysis (SLED), extended daily dialysis (EDD), or continuous renal replacement therapy (CRRT).[96]Palevsky PM, Zhang JH, O'Connor TZ, et al; VA/NIH Acute Renal Failure Trial Network. Intensity of renal support in critically ill patients with acute kidney injury. N Engl J Med. 2008 Jul 3;359(1):7-20. https://www.nejm.org/doi/full/10.1056/NEJMoa0802639 http://www.ncbi.nlm.nih.gov/pubmed/18492867?tool=bestpractice.com Major commonly used modalities include continuous venovenous hemofiltration (CVVH), continuous venovenous hemodialysis (CVVHD), and continuous venovenous hemodiafiltration (CVVHDF).
CRRT is mostly used in hemodynamically unstable patients (e.g., patients with sepsis or severe congestive heart failure) or those in whom aggressive ultrafiltration within the conventional 4-to 6-hour treatment of hemodialysis would not be tolerated.
Studies have shown that intensive dialysis in critically ill patients with AKI confers no increased benefit.[96]Palevsky PM, Zhang JH, O'Connor TZ, et al; VA/NIH Acute Renal Failure Trial Network. Intensity of renal support in critically ill patients with acute kidney injury. N Engl J Med. 2008 Jul 3;359(1):7-20. https://www.nejm.org/doi/full/10.1056/NEJMoa0802639 http://www.ncbi.nlm.nih.gov/pubmed/18492867?tool=bestpractice.com [97]Tolwani AJ, Campbell RC, Stofan BS, et al. Standard versus high-dose CVVHDF for ICU-related acute renal failure. J Am Soc Nephrol. 2008 Jun;19(6):1233-8. https://jasn.asnjournals.org/content/19/6/1233.full http://www.ncbi.nlm.nih.gov/pubmed/18337480?tool=bestpractice.com [98]Bellomo R, Cass A, Cole L, et al; RENAL Replacement Therapy Study Investigators. Intensity of continuous renal-replacement therapy in critically ill patients. N Engl J Med. 2009 Oct 22;361(17):1627-38. https://www.nejm.org/doi/10.1056/NEJMoa0902413 http://www.ncbi.nlm.nih.gov/pubmed/19846848?tool=bestpractice.com [99]Chertow GM, Burdick E, Honour M, et al. Acute kidney injury, mortality, length of stay, and costs in hospitalized patients. J Am Soc Nephrol. 2005 Nov;16(11):3365-70. http://jasn.asnjournals.org/cgi/content/full/16/11/3365 http://www.ncbi.nlm.nih.gov/pubmed/16177006?tool=bestpractice.com [109]Jun M, Heerspink HJ, Ninomiya T, et al. Intensities of renal replacement therapy in acute kidney injury: a systematic review and meta-analysis. Clin J Am Soc Nephrol. 2010 Jun;5(6):956-63. http://www.ncbi.nlm.nih.gov/pubmed/20395356?tool=bestpractice.com
Early dialysis appeared to reduce mortality compared with a delayed strategy in one small single-center randomized trial of critically ill patients with AKI,[100]Zarbock A, Kellum JA, Schmidt C, et al. Effect of early vs delayed initiation of renal replacement therapy on mortality in critically ill patients with acute kidney injury: the ELAIN randomized clinical trial. JAMA. 2016 May 24-31;315(20):2190-9. https://jamanetwork.com/journals/jama/fullarticle/2522434 http://www.ncbi.nlm.nih.gov/pubmed/27209269?tool=bestpractice.com but a larger study and meta-analysis found no benefit associated with early initiation of renal replacement therapy.[101]Gaudry S, Hajage D, Schortgen F, et al. Initiation strategies for renal-replacement therapy in the intensive care unit. N Engl J Med. 2016 Jul 14;375(2):122-33. http://www.ncbi.nlm.nih.gov/pubmed/27181456?tool=bestpractice.com [102]Bhatt GC, Das RR. Early versus late initiation of renal replacement therapy in patients with acute kidney injury - a systematic review & meta-analysis of randomized controlled trials. BMC Nephrol. 2017 Feb 28;18(1):78. https://bmcnephrol.biomedcentral.com/articles/10.1186/s12882-017-0486-9 http://www.ncbi.nlm.nih.gov/pubmed/28245793?tool=bestpractice.com
obstructive renal failure
Treatment of obstructive renal failure requires mechanical decompression at the level of obstruction.
Bladder catheter placement should be done in all cases of AKI if bladder outlet obstruction cannot be quickly ruled out by ultrasound.
Further decompression more proximal in the genitourinary tract may be required if bladder neck obstruction is not the cause of the obstruction.
Urologic or surgical assistance for ureteral stenting, urinary diversion, debulking procedures, or other case-specific requirements may become necessary.
Surgical consultation may be needed if the cause is tumor with mass effect.
Primary options
ureteral stenting: if there is a ureteral stricture, stone or extrinsically obstructing mass
OR
lithotripsy: stones present at the ureteropelvic junction causing obstruction may require lithotripsy or surgical removal
OR
exploratory laparotomy: compressing tumors may require surgical removal; may be done following ureteral stenting
OR
percutaneous nephrostomy: placement of a catheter into the renal pelvis percutaneously for drainage of urine from a distal obstruction may be done by a urologist, surgeon or interventional radiologist
Treatment recommended for SOME patients in selected patient group
Diuretics should not be used in suspected complete obstruction.
The use of diuretics in the management of AKI is primarily for volume control.
Diuretic-unresponsive volume overload is an indication to proceed to renal replacement therapy by means of dialysis or filtration.
Impaired urine production and volume expansion are commonly seen in cases of AKI.
Loop diuretics (e.g., furosemide) and metolazone may be effective in promoting diuresis, although diuretic resistance is often seen.
Patients also require sodium restriction.
It is important to remove or minimize any nephrotoxins.
Primary options
furosemide: 40-80 mg intravenously initially, increase by 20 mg/dose increments every 2 hours as necessary until clinical response
Secondary options
torsemide: 20 mg intravenously once daily initially, increase gradually according to response, maximum 200 mg/day
OR
bumetanide: 1-2 mg intravenously initially, may repeat in 2-3 hours for up to 2 doses if necessary, maximum 10 mg/day
OR
metolazone: 5-20 mg orally once daily
Treatment recommended for SOME patients in selected patient group
Nephrologist consultation is recommended.
Conventional hemodialysis is used in hemodynamically stable patients. Other modes of renal replacement include sustained low-efficiency dialysis (SLED), extended daily dialysis (EDD), or continuous renal replacement therapy (CRRT) if the patient is hemodynamically unstable despite full support.
Renal replacement therapy may be required to manage complications of obstruction while surgical interventions are planned and implemented.
Choose a patient group to see our recommendations
Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer
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