32 yo man presented with kidney failure. His tox screen was positive for cocaine. He was normotensive and physical exam was unremarkable. BUN was 52 mg/dL and Cr 8.1 mg/dL. Sodium was 139 mEq/L, potassium 4.9 mEq/L, chloride 103 mEq/L and bicarbonate 17 mEq/L. Calcium was 8.0, Urinalysis had 1+ protein, 3-5 WBC/hpf and 1-3 RBC/hpf. Envelope shaped and needle-like crystals were noted on sediment. Renal ultrasound was negative for obstruction.
The renal biopsy proves that the diagnosis is:
A. Kappa light chain cast nephropathy
B. Acute phosphate nephropathy
C. Ethylene glycol toxicity
D. Primary hyperoxaluria, Type I