Acute interstitial nephritis

Acute interstitial nephritis is inflammation of the renal interstitium.   It accounts for around 15% of cases of acute renal failure. 

Presentation 

• Acute renal failure 
• Systemic features (present in around 5%)
• Fever
• Rash 
• Arthralgia 

Causes 

• Infection 
• Bacterial infections – Legionella, Staphylococci, Streptococci, Yersinia, syphilis, lyme disease and many others
• Viral – CMV, EBV, hep C, HSV, HIV 
• Medication 
• Antibiotics – especially cephalosporins, penicillin 
• NSAIDs 
• Diuretics 
• Others – including allopurinol 
• Other 
• SLE,  Sjogrens,  Wegeners,  Sarcoidosis, Primary biliary cirrhosis

Investigation 

• ? urinary eosinophils 
• ? renal biopsy if patient not improving – look for plasma cell and lymphocytic infiltrates. 

Treatment 

• Supportive 
• Stop any precipitating drugs 

Small print gem: urinary eosinophils are found in acute interstitial nephritis, prostatitis, cystitis, bladder carcinoma, renal atheroembolic disease and rapidly progressive glomerulonephritis 

References:

Kodner, C. and Kudrimoti, A. Diagnosis and management of acute interstitial nephritis. Am Fam Physician. 2003; 67(12): 2527-2534. 

Michel, D. and Kelly, C. Acute interstitial nephritis. J Am Soc Nephrol. 1998; 9(3): 506-515.