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From Citizendium, the Citizens' Compendium

Acute kidney injury, previously called acute renal failure, is defined as as "An abrupt (within 48 hours) reduction in kidney function currently defined as an absolute increase in serum creatinine of more than or equal to 0.3 mg/dl (≥ 26.4 μmol/l), a percentage increase in serum creatinine of more than or equal to 50% (1.5-fold from baseline), or a reduction in urine output (documented oliguria of less than 0.5 ml/kg per hour for more than six hours)."^[1]

Contents 1 Classification 1.1 Prerenal 1.2 Intrarenal 1.3 Post-renal 2 Treatment 2.1 Renal replacement therapy 3 References 4 See also

Classification

Prerenal

This is characterized by:

• Urinary sodium < 15 mmol/liter^[2]
• Fractional excretion of sodium in the urine of < 1%^[2][3]
• Fractional excretion of urea nitrogen < 35%. ^[2]
• Ratio of urinary to plasma creatinine of > 20.^[2]

Causes include:

• Hypovolemia
• Hepatorenal syndrome
• Vascular disease

Intrarenal

Also simply called 'renal', this is characterized by fractional excretion of sodium in the urine of > 1%.^[3] Causes include:

• Glomerulonephritis (GN). This is characterized by significant proteinuria, red cells in the urine (possibly dysmorphic in appearance), and red-cell casts.^[4] GN may be caused by vasculitis.
• Acute tubular necrosis (ATN). ATN is characterized by pigmented granular casts in the urine sediment.^[4] Causes of ATN include radiocontrast media and non-steroidal anti-inflammatory agents.
• Interstitial nephritis.
• Drug induced. Many drugs can cause acute kidney injury. Vancomycin is associated with acute kidney injury if trough levels are above 15 microg/mL.^[5]

Post-renal

This is characterized by symptoms of obstruction and sometimes by anuria.

Treatment

The underlying cause of the kidney injury should be treated. Diuresis has been investigated as a nonspecific treatment, but no benefit was found.^[6]

If fluid resuscitation is used, the type of fluid probably does not matter according to a meta-analysis of randomized controlled trials by the Cochrane Collaboration.^[7]

Renal replacement therapy

For more information, see: Renal replacement therapy

References

1. ↑ Mehta RL, Kellum JA, Shah SV, et al (2007). "Acute Kidney Injury Network: report of an initiative to improve outcomes in acute kidney injury" 11 (2): R31. DOI:10.1186/cc5713. PMID 17331245.
2. ↑ ^{2.0 2.1 2.2 2.3} Steinman TI, Samir AE, Cornell LD (August 2008). "Case records of the Massachusetts General Hospital. Case 27-2008. A 64-year-old man with abdominal pain, nausea, and an elevated level of serum creatinine". N. Engl. J. Med. 359 (9): 951–60. DOI:10.1056/NEJMcpc0804600. PMID 18753652.
3. ↑ ^3.0 3.1 Miller TR, Anderson RJ, Linas SL, et al (1978). "Urinary diagnostic indices in acute renal failure: a prospective study". Ann. Intern. Med. 89 (1): 47–50. PMID 666184.
4. ↑ ^4.0 4.1 Rabb H, Colvin RB (2007). "Case records of the Massachusetts General Hospital. Case 31-2007. A 41-year-old man with abdominal pain and elevated serum creatinine". N. Engl. J. Med. 357 (15): 1531–41. DOI:10.1056/NEJMcpc079024. PMID 17928602.
5. ↑ Hidayat LK, Hsu DI, Quist R, Shriner KA, Wong-Beringer A (2006). "High-dose vancomycin therapy for methicillin-resistant Staphylococcus aureus infections: efficacy and toxicity". Arch. Intern. Med. 166 (19): 2138–44. DOI:10.1001/archinte.166.19.2138. PMID 17060545.
6. ↑ Ho KM, Sheridan DJ (2006). "Meta-analysis of frusemide to prevent or treat acute renal failure". BMJ 333 (7565): 420. DOI:10.1136/bmj.38902.605347.7C. PMID 16861256.
7. ↑ Perel P, Roberts I (2007). "Colloids versus crystalloids for fluid resuscitation in critically ill patients". Cochrane Database Syst Rev (4): CD000567. DOI:10.1002/14651858.CD000567.pub3. PMID 17943746.

See also

• Chronic kidney disease