From the Guidelines
The treatment of post-renal acute kidney injury (AKI) should focus on promptly relieving the urinary tract obstruction and addressing the underlying cause, with careful monitoring and management of potential complications, such as fluid and electrolyte imbalances, as evidenced by recent clinical guidelines 1. When managing post-renal AKI, it is essential to consider the principles outlined in the treatment of acute kidney injury in various contexts, including the discontinuation of potentially nephrotoxic agents and the management of fluid status, as suggested in the expert review on the evaluation and management of acute kidney injury in patients with cirrhosis 1.
Key Considerations
- Immediate relief of urinary tract obstruction through catheterization, nephrostomy tube placement, or ureteral stenting
- Monitoring of urine output, electrolytes, and fluid balance to manage post-obstructive diuresis
- Replacement therapy for significant fluid and electrolyte losses
- Addressing the underlying cause of obstruction, whether it's nephrolithiasis, benign prostatic hyperplasia, malignancy, or other causes
- Supportive care, including maintaining adequate hydration and correcting electrolyte imbalances
Management Strategies
- Insertion of a Foley catheter for lower urinary tract obstructions
- Percutaneous nephrostomy tubes or retrograde ureteral stents for upper tract obstructions
- Medical expulsive therapy using alpha-blockers like tamsulosin 0.4 mg daily for nephrolithiasis
- Alpha-blockers and 5-alpha reductase inhibitors for benign prostatic hyperplasia
- Oncologic intervention for malignancy-related obstructions
- Administration of albumin 1 g/kg/d for 2 days if the serum creatinine shows doubling from baseline, as part of the management of acute kidney injury, particularly in contexts like cirrhosis 1
Monitoring and Supportive Care
- Close monitoring of urine output, vital signs, and fluid status
- Use of echocardiography or CVP monitoring if indicated
- Replacement of fluid losses and administration of intravenous fluids as needed
- Correction of electrolyte imbalances, particularly potassium, sodium, and magnesium
- Management of complications, such as urinary tract infections, with appropriate antibiotics
From the Research
Treatment of Post-Renal Acute Kidney Injury (AKI)
- The treatment of post-renal AKI involves addressing the underlying cause of the urinary tract obstruction, and supportive care such as fluid management and kidney replacement therapy (KRT) 2.
- In severe post-renal AKI, the occurrence of post-obstructive diuresis (POD) is a frequent event that predicts renal recovery without severe chronic kidney failure 3.
- Predictors of POD occurrence include higher serum creatinine, higher serum bicarbonate, and urinary retention on admission 3.
- Predictors of severe chronic renal failure (CRF) persistence include lower blood haemoglobin, lower serum bicarbonate, longer time from admission to the release of obstruction, and absence of POD 3.
Management of AKI
- Management of AKI is founded on treating the underlying cause, but supportive care via fluid management, vasopressor therapy, and KRT is also crucial 2.
- Blood pressure targets are often higher in AKI, and these can be achieved with fluids and vasopressors 2.
- Initiation of KRT is controversial, and studies have not consistently demonstrated any benefit to early start dialysis 2.
- Medications become a key aspect of AKI management because changes in renal function and dialysis support can lead to issues with both toxicities and underdosing 2.
Prevention and Early Detection of AKI
- Prevention and early detection of AKI are essential, as AKI can be lethal and has a poor prognosis in critically ill patients 4.
- Long-term consequences of AKI include chronic kidney disease (CKD) and cardiovascular morbidity 4.
- Early determination of etiology, management, and long-term follow-up of AKI are essential to prevent further insult to the kidney 5, 4.