Medication Summary
For acute allergic interstitial nephritis, if no spontaneous recovery in renal function is observed after cessation of the offending agent, implementing a short course of steroid therapy is generally recommended. No controlled studies exist on the effect of corticosteroids; therefore, no well-defined dosage and duration exist. Most practitioners recommend a relatively high dose (eg, 1 mg/kg prednisone) with a rapidly tapering regimen within several weeks.
Glucocorticoids
Class Summary
Glucocorticoid agents have immunosuppressant effects and are used for treatment of autoimmune disorders.
Prednisone (Sterapred)
Prednisone has anti-inflammatory properties and causes profound and varied metabolic effects by modifying the body's immune response to diverse stimuli. This agent may decrease inflammation by reversing increased capillary permeability and suppressing polymorphonuclear lymphocyte (PMN) activity. Prednisone also stabilizes lysosomal membranes and suppresses lymphocytes and antibody production.
Chelating agents
Class Summary
These agents promote the excretion of lead.
Succimer (Chemet)
Succimer is a metal chelator, an analogue of dimercaprol that is used in lead poisoning. This agent is particularly useful in children with lead blood levels > 45 mcg/dL. Succimer is approved for chelation therapy in children for lead poisoning. However, its value in chronic lead nephropathy is not established.
Edetate calcium disodium (Calcium Disodium Versenate)
Edetate is used for lead chelation; only the calcium disodium preparation should be used. In the context of this article, use of this medication is confined to testing (ie, to perform the ethylenediaminetetraacetic acid [EDTA] lead mobilization test for diagnosing lead as the etiology of chronic tubulointerstitial nephritis). Extended therapy with this agent to reduce body lead stores may be of possible benefit.
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Tubulointerstitial nephritis: Kidney biopsy reveals acute interstitial nephritis. The renal cortex shows a diffuse interstitial, predominantly mononuclear, inflammatory infiltrate with no changes to the glomerulus. Tubules in the center of the field are separated by inflammation and edema, as compared with the more normal architecture in the right lower area (periodic acid–Schiff, 40 X).
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Tubulointerstitial nephritis. On a kidney biopsy, the diagnosis of acute interstitial nephritis is based on the active inflammatory infiltrate on the right with unaffected glomeruli. Interstitial edema and fibrosis are present on the left side of the field, where some tubules show thickened basement membrane (hematoxylin and eosin, 20 X).
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Tubulointerstitial nephritis. Kidney biopsy shows acute interstitial nephritis. The interstitium is expanded by mononuclear inflammatory infiltrate and edema. Acute tubular damage is present; some tubules are distended and contain granular casts (hematoxylin and eosin, 40 X).
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Tubulointerstitial nephritis. Kidney biopsy shows acute crescentic glomerulonephritis. The glomerular tuft is compressed by the proliferation of epithelial cells, forming a crescent. In addition, the interstitium shows mononuclear inflammatory infiltrate and edema (periodic acid–Schiff, 40 X).
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Tubulointerstitial nephritis. Kidney biopsy shows acute interstitial nephritis. The mononuclear inflammatory infiltrate contains abundant eosinophils, suggesting an allergic etiology. Severe tubular damage is observed (hematoxylin and eosin, 40 X).
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Tubulointerstitial nephritis. Kidney biopsy shows acute interstitial nephritis. The inflammatory infiltrate forms an ill-defined granuloma, suggesting allergic or infectious etiologies. A partially destroyed tubule is present (periodic acid–Schiff, 40 X).
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Tubulointerstitial nephritis. Kidney biopsy shows chronic tubulointerstitial nephritis. The interstitium is expanded by fibrosis, with distortion of tubules and periglomerular fibrosis. Glomeruli do not show pathologic changes (hematoxylin and eosin, 20 X).
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Tubulointerstitial nephritis. Kidney biopsy in interstitial nephritis shows a cholesterol microembolism. The 2 arterioles in the center are occluded by elongated crystals (hematoxylin and eosin, 20 X).
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Tubulointerstitial nephritis. Kidney biopsy in interstitial nephritis shows a cholesterol microembolism. The arteriole in the center of the field has a thickened wall. The lumen is occluded by elongated spaces, corresponding to dissolved crystals surrounded by cellular reaction. The 2 glomeruli flanking the arteriole are sclerotic and hardly recognizable (hematoxylin and eosin, 40 X).