From the Guidelines
The management approach for unresolving interstitial tubular nephritis with impaired renal function involves prompt withdrawal of the offending agent, corticosteroid therapy, and supportive care, with the cornerstone of treatment being prednisone, typically started at 0.5-1 mg/kg/day, as recommended by the most recent guidelines 1. The treatment approach should be guided by the severity of the renal impairment, with grading of the nephritis or acute kidney injury (AKI) based on creatinine levels above baseline, as outlined in the guidelines 1.
- For grade 1 nephritis, consideration should be given to temporarily holding immune checkpoint inhibitors (ICPi) and evaluating for other causes of renal impairment, such as recent IV contrast, medications, and fluid status 1.
- For grade 2 nephritis, ICPi should be held temporarily, and nephrology consultation should be sought, with administration of 0.5-1 mg/kg/day prednisone equivalents if other etiologies are ruled out 1.
- For more severe grades of nephritis, permanent discontinuation of ICPi and administration of higher doses of corticosteroids may be necessary, with consideration of dialysis support in severe cases 1. Supportive measures, including maintaining adequate hydration, electrolyte management, and blood pressure control, are also crucial in the management of unresolving interstitial tubular nephritis with impaired renal function 1.
- Regular monitoring of renal function with serum creatinine and estimated GFR measurements is essential to guide treatment and tapering of corticosteroids 1.
- In cases where there is no improvement or worsening of renal function despite corticosteroid therapy, consideration should be given to alternative immunosuppressive agents, such as mycophenolate mofetil or cyclophosphamide 1.
From the Research
Management Approach for Unresolving Interstitial Tubular Nephritis
The management of unresolving interstitial tubular nephritis with impaired renal function involves several key considerations:
- Identification and discontinuation of the offending agent: In cases where the interstitial nephritis is suspected to be caused by a drug, discontinuing the drug is crucial 2, 3, 4, 5.
- Corticosteroid therapy: Corticosteroids are a mainstay of treatment for interstitial nephritis, particularly for acute interstitial nephritis (AIN) 6, 5.
- Immunosuppressive therapy: For cases that are refractory to corticosteroids, immunosuppressive agents like mycophenolate mofetil (MMF) may be considered 6.
- Renal biopsy: A kidney biopsy can provide a definitive diagnosis and help identify the underlying cause of the interstitial nephritis 3, 4, 5.
- Monitoring and supportive care: Patients with impaired renal function require close monitoring of their kidney function and may need supportive care to manage complications such as electrolyte imbalances and fluid overload.
Specific Treatment Considerations
- Drug-induced interstitial nephritis: Discontinuation of the offending drug and initiation of corticosteroid therapy are key components of treatment 2, 3, 4, 5.
- Steroid-resistant cases: The use of alternative immunosuppressive agents like MMF may be beneficial in steroid-resistant cases 6.
- Chronic interstitial nephritis: Management may involve avoiding further exposure to nephrotoxic agents and potentially using immunosuppressive therapy to slow disease progression 2.