What is the approach to Acute Kidney Injury (AKI)?

From the Guidelines

Acute Kidney Injury (AKI) should be managed through a systematic approach focusing on early recognition, identifying and treating underlying causes, and preventing further kidney damage, as recommended by the Kidney Disease: Improving Global Outcomes (KDIGO) conference 1. The approach to AKI involves several key steps, including:

• Assessing the patient's volume status and ensuring adequate hydration while avoiding volume overload
• Discontinuing nephrotoxic medications, including NSAIDs, aminoglycosides, contrast agents, and certain antibiotics
• Monitoring fluid balance, daily weights, and strict intake/output measurements
• Obtaining baseline laboratory values, including serum creatinine, BUN, electrolytes, and urinalysis, and following these parameters regularly to track kidney function
• Classifying the AKI as prerenal, intrinsic, or postrenal to guide specific interventions Some of the key considerations in managing AKI include:
• Determining the optimal indications and targets for fluid and vasoactive drugs to improve kidney outcomes in acute medical illness and in the perioperative setting 1
• Investigating the optimal method of administering fluid for preventing or mitigating AKI, including the route, rate, volume, and frequency of boluses 1
• Exploring the role of sodium bicarbonate in patients with AKI and metabolic acidosis 1
• Considering the use of vasoconstrictors and albumin in patients with AKI, particularly in those with cirrhosis and ascites 1 The management of AKI should be guided by the KDIGO clinical practice guideline, which provides a comprehensive approach to the prevention and treatment of AKI 1. Key aspects of this guideline include:
• Early recognition and diagnosis of AKI
• Identification and treatment of underlying causes
• Prevention of further kidney damage
• Use of renal replacement therapy (dialysis) for severe cases
• Nutritional support, including protein restriction and potassium and phosphate restriction as needed.

From the Research

Approach to Acute Kidney Injury (AKI)

The approach to AKI involves a thorough history and physical examination to categorize the underlying cause as prerenal, intrinsic renal, or postrenal 2. Initial evaluation and management of AKI includes:

• Laboratory work-up
• Medication adjustment
• Identification and reversal of underlying cause
• Referral to appropriate specialty care

Diagnosis and Management

Accurate diagnosis of the underlying cause is key to successful management and includes:

• Focused history and physical examination
• Serum and urine electrolyte measurements
• Renal ultrasonography when risk factors for a postrenal cause are present 3 General management principles for AKI include:
• Determination of volume status
• Fluid resuscitation with isotonic crystalloid
• Treatment of volume overload with diuretics
• Discontinuation of nephrotoxic medications
• Adjustment of prescribed drugs according to renal function 3

Prevention and Therapy Strategies

There is no effective pharmacological therapy that prevents the evolution or reverses the injury once established, and renal replacement therapy is the only current alternative available for renal patients 4. Emerging strategies from basic science toward the anticipation of features, treatment of AKI, and new treatments using pharmacological and stem cell therapies are being discussed 4.

Medical Causes and Pathogenesis

AKI is classically defined and staged based on serum creatinine concentration and urine output rates, and the etiology of AKI is conceptually classified into three general categories: prerenal, intrarenal, and postrenal 5. The timely and accurate identification of AKI and a better understanding of the pathophysiological mechanisms that cause kidney dysfunction are essential.

Fluid Management and Use of Diuretics

Critically ill adult patients at risk for or with AKI require careful attention to their hemodynamic status, and increasing evidence suggests that isotonic crystalloids should be used instead of colloids for initial expansion of intravascular volume in patients at risk for AKI or with AKI 6. Diuretics may prevent or treat fluid overload and may also affect kidney function, but the efficacy of these procedures in critically ill AKI patients needs to be confirmed with randomized controlled trials 6.