0521779407-20 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 21:22
Tubulointerstitial Renal Disease 1463➣fever (75% of cases)
➣nonspecific arthralgias (10% of cases)
■Chronic TIN may present with:
➣insidious, symptomatic increase in BUN and creatinine
➣hypertension
➣inability to concentrate urine
➣polyuria, nocturia
➣azotemia, malaise, anemia
➣renal tubular acidosis
➣advanced renal insufficiency/need for dialysis
tests
Laboratory
■Hematology – CBC (add differential with acute TIN)
➣Acute TIN: eosinophilia – in 80% of cases caused by methicillin- 39% of cases caused by other drugs
➣Chronic TIN: anemia (decreased EPO production)
■Metabolic Profile
➣Acute TIN:
frequently has increased BUN and creatinine
no specific pattern of RTA, electrolyte or acid-base disturbance
mimics ARF
➣Chronic TIN:
elevated BUN and creatinine
■Urinalysis
➣Abnormalities reflect site and severity of tubular damage
➣Acute TIN:
mild to moderate proteinuria, <2 g/24 hours (60%–80% of
cases)
nephrotic range proteinuria rare except with minimal change
disease associated with NSAID use
microscopic hematuria (50%–90% of cases), RBC casts rare
pyuria (50% 0f cases), WBC casts
eosinophiluria – >5% of urine WBC stain with Hansel’s stain
(low positive predictive value – also seen with ARF)
glucosuria (with normal serum glucoses)
bicarbonaturia (proximal RTA)
inability to acidify urine (urine pH > 5.5)
distal RTA
➣Chronic TIN
inability to concentrate urine, low specific gravity