What is the management for a 16-year-old with impaired renal function?

Management of Impaired Renal Function in a 16-Year-Old

A 16-year-old with elevated creatinine and BUN requires prompt referral to a pediatric nephrologist for comprehensive evaluation and management, with initial treatment focusing on identifying the underlying cause while implementing renoprotective measures including ACE inhibitors or ARBs for hypertension and proteinuria. 1

Initial Assessment

Diagnostic Evaluation

• Measure urine albumin-to-creatinine ratio to assess for proteinuria 1
• Calculate estimated glomerular filtration rate (eGFR) 1
• Screen for hypertension (defined as ≥95th percentile for age, sex, and height or ≥130/80 mmHg in adolescents ≥13 years) 1
• Consider kidney biopsy if etiology is unclear 1, 2
• Genetic testing if suspicion for hereditary kidney disease 1, 2

Common Causes to Consider

• Primary glomerular disease (nephrotic syndrome)
• Secondary causes (diabetes, hypertension, autoimmune disease)
• Congenital/hereditary kidney disorders
• Medication-induced nephrotoxicity
• Post-infectious glomerulonephritis

Treatment Algorithm

1. Hypertension Management

• If blood pressure is elevated (≥95th percentile or ≥130/80 mmHg):
  • Start with ACE inhibitor or ARB as first-line therapy 1
  • Target blood pressure <90th percentile or <130/80 mmHg 1
  • Important: Provide reproductive counseling for females due to teratogenic effects of ACE inhibitors/ARBs 1

2. Proteinuria Management

• For mild-moderate proteinuria (30-299 mg/g creatinine):
  • ACE inhibitor or ARB recommended 1
• For severe proteinuria (≥300 mg/g creatinine):
  • Higher doses of ACE inhibitor or ARB 1
  • Consider additional therapies based on underlying diagnosis

3. Nephrotic Syndrome Management

If steroid-sensitive nephrotic syndrome:

• Initial treatment with oral prednisone 1
• For frequently relapsing cases, consider steroid-sparing agents 1

If steroid-resistant nephrotic syndrome:

• Calcineurin inhibitors (CNIs) are first-line therapy 2
• Continue CNIs for minimum 6 months to assess response 2
• Consider mycophenolate mofetil if CNIs fail 2

4. Supportive Care

• Fluid management: Avoid excessive fluid restriction or overload 1
• Dietary modifications:
  • Sodium restriction if edematous
  • Protein intake appropriate for age
  • Potassium restriction if hyperkalemic
• Monitor for and treat electrolyte imbalances
• Avoid nephrotoxic medications 3

Monitoring Parameters

• Regular assessment of kidney function (creatinine, BUN, eGFR) 1
• Urine albumin-to-creatinine ratio monitoring 1
• Blood pressure monitoring
• Growth and development monitoring
• Medication levels for certain therapies (e.g., CNIs)

Indications for Nephrology Referral

Referral to nephrology is recommended in cases of:

• Uncertainty of etiology
• Worsening proteinuria
• Decreasing eGFR
• Resistant hypertension
• Need for specialized therapies 1

Prognosis and Long-term Considerations

• Risk stratification based on degree of renal impairment 4
• Early intervention improves outcomes
• Monitor for complications of chronic kidney disease:
  • Anemia
  • Metabolic bone disease
  • Growth impairment
  • Cardiovascular complications

Potential Pitfalls and Caveats

• Avoid dehydration, which can worsen renal function 3
• Use caution with contrast agents; consider prophylactic hydration if contrast studies are necessary 5
• Adjust medication dosages based on renal function 6
• Monitor for medication side effects, particularly with ACE inhibitors/ARBs
• Consider reproductive counseling for female adolescents on ACE inhibitors/ARBs 1

Early diagnosis and treatment are crucial to prevent progression to end-stage renal disease and improve quality of life in adolescents with impaired renal function.