What is the treatment for impaired renal function?

Treatment for Elevated BUN and Creatinine (Renal Impairment)

The primary treatment for a BUN of 90 and creatinine of 2.58 requires immediate hydration with intravenous fluids to maintain urine output of 100-150 mL/hour, discontinuation of nephrotoxic medications, and addressing underlying causes while monitoring for complications. 1

Initial Management

Immediate Interventions

• Hydration:

  • Start IV fluids promptly to decrease renal tubular damage
  • Target urine output: 100-150 mL/hour
  • Careful assessment of fluid status to avoid hypervolemia, especially in patients with oliguria 1

• Medication Management:

  • Discontinue nephrotoxic medications including:
    • NSAIDs
    • ACE inhibitors/ARBs (may cause progressive azotemia) 2
    • Contrast agents
    • Certain antibiotics
  • Hold diuretics temporarily to prevent further dehydration 1

• Correct Metabolic Abnormalities:

  • Treat hypercalcemia if present with hydration, bisphosphonates, and/or calcitonin 1
  • Correct hyperuricemia
  • Monitor and treat hyperkalemia (common in renal dysfunction) 1

Diagnostic Workup

• Urinalysis: Evaluate for hematuria, proteinuria, or abnormal urinary sediment to distinguish between functional and structural renal disease 3
• Renal ultrasound: Assess for obstruction or structural abnormalities
• Evaluate for potential causes:
  • Dehydration
  • Hypotension
  • Infection
  • Medication toxicity
  • Underlying conditions (diabetes, hypertension, heart failure, multiple myeloma)

Treatment Based on Severity and Cause

For Moderate Impairment (Creatinine 2-3 mg/dL)

• Continue IV hydration with close monitoring
• Adjust medication dosages based on estimated GFR
• Monitor electrolytes, BUN, and creatinine daily
• Avoid intravenous contrast media 1

For Severe Impairment (Creatinine >3 mg/dL)

• Consider nephrology consultation
• Hemofiltration or dialysis may be needed to:
  • Control fluid retention
  • Minimize risk of uremia
  • Allow the patient to tolerate necessary medications 1

Special Considerations for Specific Causes

If Heart Failure Related:

• Careful fluid management to avoid overload
• Consider cardiorenal-specific approaches
• Monitor for signs of volume overload during hydration 1

If Multiple Myeloma Related:

• Prompt institution of antimyeloma therapy is essential
• Consider bortezomib-based regimens (not renally cleared) 1
• Plasmapheresis may be considered in cases of light chain nephropathy 1

Monitoring and Follow-up

• Daily monitoring:

  • Serum creatinine and BUN
  • Electrolytes (particularly potassium)
  • Fluid balance (intake/output)
  • Weight

• Medication adjustments:

  • Dose adjustments for renally cleared medications
  • Avoid drugs requiring substantial renal elimination 1

Prevention of Further Injury

• Avoid nephrotoxic agents:

  • Contrast media (if necessary, use with appropriate pre-hydration)
  • NSAIDs
  • Aminoglycosides when possible

• Maintain adequate hydration but avoid excessive hydration which may paradoxically worsen outcomes 4

Common Pitfalls to Avoid

1. Relying solely on serum creatinine: Creatinine may not accurately reflect GFR, especially in elderly or malnourished patients 5

2. Excessive hydration: While hydration is important, excessive volume can worsen outcomes and increase risk of complications 4

3. Continuing nephrotoxic medications: Failure to review and adjust medication regimens is a common error

4. Missing underlying causes: Always search for potentially reversible causes of renal dysfunction 1

5. Inadequate monitoring: Renal function can deteriorate rapidly and requires close monitoring, especially in high-risk patients