Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 22-08: Interstitial Nephritis + Key Features Download Section PDF Listen +++ ++ Interstitial inflammatory response with edema and possible tubular cell damage, responsible for ~10–15% of cases of intrinsic renal failure Causes of acute interstitial nephritis Drugs (> 70% of cases), including Penicillins Cephalosporins Sulfonamides Nonsteroidal anti-inflammatory drugs Proton pump inhibitors Rifampin Phenytoin Allopurinol Infectious diseases, including Streptococcal infections Leptospirosis Cytomegalovirus Histoplasmosis Rocky Mountain spotted fever Immunologic disorders, including Systemic lupus erythematosus Sjögren syndrome Sarcoidosis Cryoglobulinemia Idiopathic Causes of chronic interstitial nephritis Obstructive uropathy Vesicoureteral reflux (reflux nephropathy) Analgesic nephropathy Heavy metals (lead, cadmium, mercury, bismuth) Multiple myeloma Gout + Clinical Findings Download Section PDF Listen +++ ++ Fever (> 80%) Transient maculopapular rash (25–50%) Arthralgias Peripheral blood eosinophilia (80%) The classic triad of fever, rash, and arthralgias is present in only 10–15% of cases + Diagnosis Download Section PDF Listen +++ ++ Peripheral blood eosinophilia (80%) Acute or chronic kidney disease White cells (95%), red cells, and white cell casts in urine Proteinuria usually modest (< 2 g/24 h) Kidney biopsy is diagnostic Differential diagnosis Acute tubular necrosis Acute glomerulonephritis Prerenal azotemia Chronic glomerulopathy (eg, diabetes) Hypertensive nephrosclerosis Obstructive uropathy + Treatment Download Section PDF Listen +++ ++ Supportive measures Removal of inciting agent In more severe cases of drug-induced interstitial nephritis, Short-term, high-dose methylprednisolone (0.5–1 g/day intravenously for 1–4 days) or Prednisone (60 mg/day orally for 1–2 weeks) followed by a taper can be used Prognosis good; recovery occurs over weeks to months Dialysis may be necessary in up to 33% Patients rarely progress to end-stage renal disease Prognosis worse in those with prolonged courses of oliguric failure and advanced age