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For further information, see CMDT Part 22-08: Interstitial Nephritis
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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
Infectious diseases, including
Immunologic disorders, including
Idiopathic
Causes of chronic interstitial nephritis
Obstructive uropathy
Vesicoureteral reflux (reflux nephropathy)
Analgesic nephropathy
Heavy metals (lead, cadmium, mercury, bismuth)
Multiple myeloma
Gout
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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
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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
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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