Internal Medicine

P1: SBT

0521779407-03 CUNY1086/Karliner 0 521 77940 7 June 7, 2007 19:6

118 Analgesic Nephropathy

tests

Laboratory

■Basic studies

➣Blood: CBC,

Na, K+,Cl−, CO2, BUN, creatinine, Ca++,Mg++, Phos.

➣Urinalysis

Possible findings include:

normal

sterile pyuria

hematuria,

low specific gravity

mild proteinuria (<2+by dipstick)

less 1 gram protein /24 hours

proteinuria may be nephrotic with NSAID tubulointerstitial

nephritis

inability to acidify urine

Imaging

■Renal ultrasound – garland pattern of calcification around the renal

pelvis suggestive of prior papillary necrosis

■Non Contrast CT – has been proposed as modality of choice to diag-

nose or exclude analgesic nephropathy- further research to validate

this technique is needed

Renal Biopsy

■infrequently needed. as diagnosis made primarily by history and

exposure

■shows interstitial nephritis; with NSAID there may be additional min-

imal change disease or membranous nephropathy

differential diagnosis

Chronic Analgesic Nephropathy

■urinary tract obstruction

■polycystic kidney disease

■hypertensive nephrosclerosis

■chronic tubulo-interstial renal disease

■hypercalcemia

■sarcoid nephropathy

■medullary cystic kidney disease

■lead nephropathy

■myeloma kidney