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Acute Interstitial Nephritis
Aka: Acute Interstitial Nephritis, Acute Tubulointerstitial Nephritis, Allergic Interstitial Nephritis, Interstitial Nephritis, AIN
- See Also
- Acute Kidney Injury
- Acute Prerenal Failure
- Acute Postrenal Failure
- Acute Kidney Injury Causes
- Medication Causes of Acute Kidney Injury
- Nephrotoxicity Risk
- Intravenous Contrast Related Acute Renal Failure
- Chronic Renal Failure
- Prevention of Kidney Disease Progression
- Pathophysiology
- Renal interstitial inflammation
- T-Cell mediated Hypersensitivity Reaction (Allergic Reaction affecting the Kidney)
- Causes
- See Infectious Causes of Acute Interstitial Nephritis (includes miscellaneous causes)
- See Medication Causes of Interstitial Nephritis
- Symptoms and Signs
- Classic triad (Methicillin induced Hypersensitivity)
- Low grade fever (>70% of cases)
- Rash (>30% of cases)
- Arthralgia (>15% of cases)
- Acute Renal Failure
- Oliguria
- Malaise
- Nausea or Vomiting
- Labs: General
- Urinalysis
- Eosinophiluria
- Proteinuria
- Fractional Excretion of Sodium >1%
- Common to intrinsic Kidney disease (ATN, GN) in which Sodium cannot be retained despite decreased perfusion
- Renal Function tests with Renal Insufficiency
- Serum Creatinine increased
- Blood Urea Nitrogen increased
- Miscellaneous
- Hyperchloremic Metabolic Acidosis
- Labs: Renal biopsy
- Inflammation of renal interstitium
- Mononuclear cell and T-Lymphocyte infiltrate
- Glomerular and vascular sparing
- Management
- Consider Corticosteroid course
- Initial: Prednisone 1 mg/kg/day PO for 2 weeks
- Next: Prednisone tapered off over 3-4 weeks
- Consider cyclophosphamide in steroid non-responders
- Eliminate possible causes
- Optimize fluid status
- Manage Hyperkalemia and other Electrolyte abnormalities
- Symptomatic relief of fever and Arthralgias
- Avoid nephrotoxic medications
- Prognosis
- Recovery in weeks if cause eliminated within 2 weeks
- Renal biopsy findings suggestive of poor prognosis
- Diffuse inflammation
- Neutrophils >1%
- Significant interstitial fibrosis
- Complications
- Acute Renal Failure
- Responsible for up to 15% of Acute Renal Failure
- Prevention
- See Prevention of Kidney Disease Progression
- References
- Kodner (2003) Am Fam Physician 67(12):2527-34 [PubMed]
- Michel (1998) J Am Soc Nephrol 9:506-15 [PubMed]