Acute interstitial nephritis Flashcards
Causes of acute intersitital nephritis (AIN)
drugs (antibiotics like bactrim, NSAIDS), infections (legionella streptococcus), systemic and autoimmune dx (SLE, sarcoidosis, Sjogren’s dx) and PPIs
Ampicillin can do it
Clinical features of acute interstitial nephritis
allergic symptoms (urticaria) new drug exposure
laboratory findings
AKI,
pyuria
hematuria
WBC casts
eosinophilia and urine eosinophil smear is positive
renal biopsy with inflammatory infiltrate and edema
management
supportive and should stop the offending drug
systemic steroids.
what other clinical manifestations are seen with AIN
the classic triad
fevers, rash, and eosinophilia (though all 3 only present in 10% of cases)
urinalysis of Acute interstitial nephritis
hematuria, pyruia with WBC casts, variable proteinuria, and urinary eosinophils are supportive but no specific or sensitive
Renal biopsy is diagnostic but not necessary
difference between cholesterol embolization leading to renal failure and AIN leading to renal failure
cholesterol embolization will have renal failure and sterile pyruia and WBC casts (maybe also low complement levels) but also needs hx of endovascular procedure and atherosclerotic dx in hix
Contrast induced nephropathy occurs
see renal failure in 24-48 hrs post exposure
UA should show muddy brown casts and not WBC casts.
immune complex mediated glomerulonephritis is characterized by:
acute renal failure and dysmorphic red blood cells and red blood cell casts and not WBC casts.
management of suspected AIN
stop the offending drug immediately. Renal biopsy is diagnostic but not required.
Side effects of Bactrim
skin - Steven Johnson syndrome, TEN (toxic epidermal necrolysis) exfoliative dermatitis
Hematological: megaloblastic pancytopenia (folate deficiency) and hemolytic anemia in pts who have G6PD deficiency
Renal: hyperkalemia, impairs tubular secretion of Cr without affecting GFR
see crystalluria
interstitial nephritis
