A 60-year-old woman with 3 years of swelling in hands and feet. BP 180/130 mmHg, facial skin without wrinkles, perioral furrows. Urinary protein (++) (1.9g/d), urinary RBCs 25-30/HPF, Hb 100g/L, BUN 20.8 mmol/L, ANA positive. When the patient develops nausea, vomiting, and retinal hemorrhage, the most likely diagnosis is: