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Acute kidney injury: Difference between revisions
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<section begin="clinical biochemistry" /><section begin="radiology" />'''Acute kidney injury''' (AKI) is a clinical syndrome which is characterised by an acute decrease kidney function (<abbr>[[Glomerular filtration rate|GFR]])</abbr> (over hours or days), as evidenced by elevated creatinine. There may also be accumulation of urinary waste products and [[Oliguria and anuria|oliguria/anuria]], but not always. The cause may be prerenal, renal, or postrenal, but the most common causes are prerenal and [[acute tubular necrosis]]. <section end="clinical biochemistry" /> | <section begin="A&IC" /><section begin="clinical biochemistry" /><section begin="radiology" />'''Acute kidney injury''' (AKI) is a clinical syndrome which is characterised by an acute decrease kidney function (<abbr>[[Glomerular filtration rate|GFR]])</abbr> (over hours or days), as evidenced by elevated creatinine. There may also be accumulation of urinary waste products and [[Oliguria and anuria|oliguria/anuria]], but not always. The cause may be prerenal, renal, or postrenal, but the most common causes are prerenal and [[acute tubular necrosis]]. AKI is a common problem in [[Critical illness|critically ill]] patients in the [[intensive care unit]]. <section end="clinical biochemistry" /> | ||
During the evaluation it’s important to determine whether it’s really acute or chronic, and to determine the underlying cause. Management includes treating the cause and correcting severe electrolyte disturbances. In some cases, [[renal replacement therapy]] may be required. | During the evaluation it’s important to determine whether it’s really acute or chronic, and to determine the underlying cause. Management includes treating the cause and correcting severe electrolyte disturbances. In some cases, [[renal replacement therapy]] may be required. | ||
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[[Oliguria and anuria|Oliguria]] is the most common symptom, but in many cases it’s asymptomatic. There may be symptoms of the underlying cause, or symptoms of [[uraemia]].<section begin="radiology" /><section begin="clinical biochemistry" /> | [[Oliguria and anuria|Oliguria]] is the most common symptom, but in many cases it’s asymptomatic. There may be symptoms of the underlying cause, or symptoms of [[uraemia]].<section begin="radiology" /><section begin="clinical biochemistry" /> | ||
== Diagnosis and evaluation == | == Diagnosis and evaluation == | ||
<section end="radiology" />In the evaluation of AKI, we use serum [[creatinine]] as a marker of [[Kidney function tests|kidney function]] (''normal range 60 – 100 µmol/L)''; the estimated [[Glomerular filtration rate|GFR]] (eGFR) can ''not'' be used, as it's estimated according to formulas which are made for chronic kidney disease. The definition of AKI requires either (1) an increase in serum creatinine by 27 µmol/L, or (2) an increase to more than 150% of baseline serum creatinine over 48 hours, or (3) a decrease in urine volume to < 3 mL/kg over 6 hours.<section end="clinical biochemistry" /> | <section end="radiology" />In the evaluation of AKI, we use serum [[creatinine]] as a marker of [[Kidney function tests|kidney function]] (''normal range 60 – 100 µmol/L)''; the estimated [[Glomerular filtration rate|GFR]] (eGFR) can ''not'' be used, as it's estimated according to formulas which are made for chronic kidney disease. The definition of AKI requires either (1) an increase in serum creatinine by 27 µmol/L, or (2) an increase to more than 150% of baseline serum creatinine over 48 hours, or (3) a decrease in urine volume to < 3 mL/kg over 6 hours.<section end="clinical biochemistry" /><section end="A&IC" /> | ||
During the evaluation of a person with acute kidney injury, it’s important to answer these 5 questions: | During the evaluation of a person with acute kidney injury, it’s important to answer these 5 questions: | ||
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If the cause remains unclear despite these investigations, a [[renal biopsy]] may be required. | If the cause remains unclear despite these investigations, a [[renal biopsy]] may be required. | ||
<section begin="A&IC" /> | |||
== Treatment == | == Treatment == | ||
Treating the underlying cause is essential, as well as correcting any severe electrolyte disorders. | Treating the underlying cause is essential, as well as correcting any severe electrolyte disorders. | ||
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If there is hypervolaemia, a [[loop diuretic]] may be used. | If there is hypervolaemia, a [[loop diuretic]] may be used. | ||
If there are indications for it, [[renal replacement therapy]] may be used. | If there are indications for it, [[renal replacement therapy]] may be used. Renal replacement therapy (RRT) is indicated if: | ||
* Oliguria or anuria | |||
* Severe hyperkalaemia | |||
* Severe acidosis | |||
* Uraemic signs | |||
* Drug overdose with dialysable drug | |||
== Prognosis == | == Prognosis == | ||
In many cases patients make a full recovery, but AKI can progress to chronic kidney disease as well. It might take months for kidney functions to recover completely, during which the patient may experience [[polyuria]] because the tubules need a long time to recover. | In many cases patients make a full recovery, but AKI can progress to chronic kidney disease as well. It might take months for kidney functions to recover completely, during which the patient may experience [[polyuria]] because the tubules need a long time to recover. | ||
<section end="A&IC" /> | |||
== References == | == References == | ||
[[Category:Nephrology]] | [[Category:Nephrology]] | ||
[[Category:Intensive care]] | |||