Acute kidney injury (AKI), previously known as acute renal failure (ARF), signifies a sudden decline in kidney function. This results in the kidneys’ inability to effectively filter waste products and maintain electrolyte balance. Diagnosis relies on assessing serum creatinine levels and urine output.
Defining AKI: Key Metrics
Clinicians use specific criteria to diagnose AKI. The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines define AKI based on changes in serum creatinine and urine output. These criteria offer a standardized approach to diagnosis.
| Increase in serum creatinine | ≥0.3 mg/dL within 48 hours or ≥1.5-fold increase from baseline within 7 days |
| Urine output |
Note that baseline creatinine is crucial for accurate assessment.
Types of AKI
AKI broadly categorizes into three main types based on the underlying cause: pre-renal, intra-renal, and post-renal. Pre-renal AKI stems from inadequate blood flow to the kidneys, often due to dehydration or heart failure. Intra-renal AKI arises from direct damage to the kidney tissue itself, encompassing conditions like acute tubular necrosis (ATN) from nephrotoxins or ischemia. Post-renal AKI results from obstruction of urine flow, such as kidney stones or tumors blocking the urinary tract. Accurate identification of the specific type guides treatment strategies.
Further Considerations
Understanding the specific type of AKI is paramount for effective treatment. Each type requires targeted interventions addressing the root cause. Prompt diagnosis and management are critical for improving patient outcomes.
