A 52-year-old man from Bangalore presents with sudden-onset severe headache, confusion, and visual disturbance. His BP is 168/105 mmHg. CBC shows Hb 9.8 g/dL, WBC 8.2 × 10⁹/L, and platelets 45 × 10⁹/L. Peripheral blood smear reveals fragmented RBCs (schistocytes), polychromasia, and reduced platelet numbers. Serum creatinine is 2.1 mg/dL, and LDH is markedly elevated at 1850 U/L. What is the most appropriate immediate next step?