Amphetamine Induced Acute Interstitial Nephritis with RBC Casts

0 98.8 F, Respiratory Rate 20/min. His admission labs showed Sodium 138 mEq/L, potassium 5.5 mEq/L, chloride 95 mEq/L, bicarbonate 14 mEq/L, BUN 193 mg/dL, Cr 16 mg/dL, phosphorus 12.4 mg/dL, WBC 7.7 cumm, Hemoglobin 13.8 g/dL, and hematocrit 39.0%, Creatine kinase 2920 mg/dL. Urinalysis revealed large blood, negative protein, specific gravity 1012, WBC 4-10/hpf, RBC>50 / HPF with many RBC casts (Fig 1), negative for eosinophils by Wright giemsa stains. All other serologies were negative including ANA, hepatitis B, hep. C, HIV, Rheumatoid factor, ASO titer, Rapid Plasma Reagin, and cryoglobulin. Serum complements reported within normal limits.