From the Guidelines
Acute kidney injury (AKI) is primarily caused by prerenal, renal, and postrenal factors, with prerenal and renal etiologies accounting for over 97% of AKI cases. The causes of AKI can be multifactorial, but they are generally categorized into these three main categories 1.
Prerenal Causes
Prerenal AKI results from impaired blood flow to the kidneys, which can be caused by:
- Hypotension
- Hypovolemia
- Decreased cardiac output
- Renal artery occlusion These conditions reduce the perfusion of the kidneys, leading to a decrease in glomerular filtration rate (GFR) 1.
Renal Causes
Renal AKI involves direct damage to the kidney tissue itself, which can occur from:
- Vasculitis
- Acute tubular necrosis
- Glomerulonephritis
- Interstitial nephritis
- Renal infection or infiltration
- Drugs and toxins These conditions damage the renal parenchyma, disrupting the kidney's ability to filter waste and maintain fluid balance 1.
Postrenal Causes
Postrenal AKI stems from urinary tract obstruction, typically caused by:
- Ureteral obstruction
- Bladder obstruction
- Urethral obstruction These conditions create back pressure, disrupting the kidney's ability to filter waste and maintain fluid balance 1. Early recognition of these causes is crucial, as prompt treatment can prevent permanent kidney damage and improve patient outcomes 1.
From the Research
Causes of Acute Kidney Injury
The causes of acute kidney injury (AKI) can be classified into three general categories: prerenal, intrarenal, and postrenal 2.
- Prerenal causes are related to decreased blood flow to the kidneys, such as dehydration, blood loss, or heart failure.
- Intrarenal causes are related to damage to the kidneys themselves, such as acute tubular necrosis caused by ischemia or nephrotoxicity.
- Postrenal causes are related to obstruction of the urinary tract, such as kidney stones or bladder outlet obstruction.
Medical Causes of AKI
Medical causes of AKI include:
- Systemic illness, such as sepsis or multi-organ failure 3
- Toxic exposure, such as nephrotoxic drugs or heavy metals 3
- Infections, such as pneumonia or urinary tract infections 4
- Trauma, such as crush injuries or severe burns 4
- Invasive procedures, such as surgery or angiography 4
Specific Causes of AKI
Specific causes of AKI include:
- Nephrotoxic drugs, such as aminoglycosides or NSAIDs 3
- Radiocontrast agents, used in imaging studies such as CT scans or angiography 5
- Sepsis, which can cause AKI through a combination of hypotension, inflammation, and oxidative stress 4
- Heart failure, which can cause AKI through decreased blood flow to the kidneys 5
Risk Factors for AKI
Risk factors for AKI include: