A 46-Year-Old Woman Is Brought to the Emergency Department After

A 46-year-old woman is brought to the emergency department after she is found unconscious. Temperature is 37.2 C (98.96 F) , blood pressure is 130/90 mm Hg, and pulse is 120/min. She is not responsive and has a dry mucous membrane. The patient is started on intravenous fluids, she starts to improve. Later, her urine output decreased and she started having flank pain. Renal microscopy shows ballooning and vacuolar degeneration of the proximal tubules. Additionally, multiple oxalate crystals were observed in the lumen. The acute kidney injury in this patient is due to one of the following?

A) Direct tubular injury due to exogenous toxin ingestion
B) Direct tubular injury from filtered monoclonal light chains
C) Increased endogenous parathyroid hormone production
D) Microthrombosis of the glomerular capillaries
E) Prerenal azotemia due to splanchnic vasodilation