5- ACUTE INTERSTITIAL NEPHRITIS

• Also known as


  Allergic interstitial nephritis
• Causes


  • Drugs (70%)
  • Autoimmune disorders
  • Infections
  • Idiopathic (10%)
• Drugs

  • NSAIDs
  • Antibiotics: penicillin, cephalosporins, quinolones (ciprofloxacin), rifampin
  • Allopurinol
  • Phenytoin
  • PPIs
  • Sulfas (sulfonamide) & sulfa derivatives (furosemide & thiazides)
• Infections


  • Legionella
  • Leptospira
  • Streptococcus
  • Yersina
  • CMV
  • EBV
• Autoimmune causes


  • SLE
  • Sjogren syndrome
  • Wegner's granulomatosis
• Presentation


  • Fever and rash
  • Azotemia on labs
  • +/- uremic symptoms
• Investigations


  1. Urinalysis for any patient with fever and rash after starting medication

  2. CBC: eosinophilia

  3. High WBCs in urinalysis (eosinophiluria)

  4. Hansel stain or Wright stain: eosinophils in urine
• Treatment


  1. Stop offending agent

  2. Admit, observe, monitor electrolytes and renal function

  3. If renal failure persists > 3 days, IV prednisone