Acute Interstitial Nephritis
- Idiosyncratic drug-induced (hypersensitivity) reaction
- Antibiotics (beta-lactams, penicillin derivatives, cephalosporins, TMP/SMX, rifampin, fluoroquinolones), NSAIDs, cimetidine, thiazides, phenytoine, allopurinol, carbamazepine
- Pt:
- Antibiotics cause a classic triad of ___, ___, and ___. It is an idiosyncratic response to the antibiotic and is not related to the amount of antibiotic or the antibiotic’s duration of use!
- NSAID-induced AIN is different in that the NSAIDs are typically ingested for months before symptoms occur. The rash, fever, and eosinophilia may not occur.
- Contrary to all other types of AIN, with NSAID-induced AIN, there is often nephrotic-range proteinuria with minimal glomerular changes.
- Note: NSAID-induced AIN (an intrinsic AKI) has a different mechanism than NSAID-induced prerenal AKI. The latter causes vasoconstriction due to prostaglandin blockage; not that dehydrated pts are at higher risk to develop this complication. So remember not to prescribe ibuprofen to febrile pts who are dehydrated or likely to develop dehydration.
- Urine sediment:
- ______, RBCs, WBCs, and WBC casts.
- Differs from GN in that it does not have significant albuminuria, RBC casts, or oval fat bodies.
- Though more specific than eosinophilia, eosinophiluria is not a very sensitive finding.
- Slight proteinuria (<1-1.5g/day); proteinuria is marked by excessive _______ that is excreted from tubules
- Tx
- Discontinue offending agent.
- If AIN persists for 3-7 days after discontinuing the drug, initiate glucocorticoid therapy for 1-2 weeks (unless offending drug is an NSAID, then do not use glucocorticoid tx)
Acute Interstitial Nephritis
- Idiosyncratic drug-induced (hypersensitivity) reaction
- Antibiotics (beta-lactams, penicillin derivatives, cephalosporins, TMP/SMX, rifampin, fluoroquinolones), NSAIDs, cimetidine, thiazides, phenytoine, allopurinol, carbamazepine
- Pt:
- Antibiotics cause a classic triad of fever, rash, and eosinophilia. It is an idiosyncratic response to the antibiotic and is not related to the amount of antibiotic or the antibiotic’s duration of use!
- NSAID-induced AIN is different in that the NSAIDs are typically ingested for months before symptoms occur. The rash, fever, and eosinophilia may not occur.
- Contrary to all other types of AIN, with NSAID-induced AIN, there is often nephrotic-range proteinuria with minimal glomerular changes.
- Note: NSAID-induced AIN (an intrinsic AKI) has a different mechanism than NSAID-induced prerenal AKI. The latter causes vasoconstriction due to prostaglandin blockage; not that dehydrated pts are at higher risk to develop this complication. So remember not to prescribe ibuprofen to febrile pts who are dehydrated or likely to develop dehydration.
- Urine sediment:
- Eosinophils, RBCs, WBCs, and WBC casts.
- Differs from GN in that it does not have significant albuminuria, RBC casts, or oval fat bodies.
- Though more specific than eosinophilia, eosinophiluria is not a very sensitive finding.
- Slight proteinuria (<1-1.5g/day); proteinuria is marked by excessive beta-2 microglobulin that is excreted from tubules
- Tx
- Discontinue offending agent.
- If AIN persists for 3-7 days after discontinuing the drug, initiate glucocorticoid therapy for 1-2 weeks (unless offending drug is an NSAID, then do not use glucocorticoid tx)