A 35-year-old male presents with acute onset fatigue, dark urine, and bilateral lower extremity edema. Laboratory studies reveal a serum creatinine of 4.2 mg/dL (baseline 0.9 mg/dL), urinalysis shows 3+ protein, 20-30 RBCs/HPF, and numerous red blood cell casts. Serologies are pending. What is the most appropriate initial management step?
✓ Correct Answer: Option B
High-dose intravenous corticosteroids are initiated empirically for suspected rapidly progressive glomerulonephritis (RPGN) to prevent irreversible kidney damage while awaiting definitive diagnosis. Renal biopsy is diagnostic, not the initial therapeutic step.