question: Q:A 26-year-old woman presents with blood in her urine for the past 2 days. She says she has had increasing urinary frequency at night for the past several days and recently noticed a reddish tinge in her urine. She is also concerned that her feet are beginning to swell, and she has been feeling increasingly fatigued for the past week. She gives no history of joint pains, rashes, or skin changes. Past medical history is relevant for an occasional bluish discoloration of her fingers during exposure to cold. Her vital signs are a pulse of 80/min, a respiratory rate of 14/min, and blood pressure of 140/88 mm Hg. On physical examination, the patient has 1+ pitting edema of her feet bilaterally. Remainder of examination is unremarkable. Laboratory findings are significant for the following:
  Serum glucose (fasting) 88 mg/dL
  Sodium 143 mEq/L
  Potassium 3.7 mEq/L
  Chloride 102 mEq/L
  Serum creatinine 1.7 mg/dL
  Blood urea nitrogen 32 mg/dL
  Cholesterol, total 180 mg/dL
  HDL-cholesterol 43 mg/dL
  LDL-cholesterol 75 mg/dL
  Triglycerides 135 mg/dL
  Hemoglobin (Hb%) 12.5 g/dL
  Mean corpuscular volume (MCV) 80 fL
  Reticulocyte count 1%
  Erythrocyte count 5.1 million/mm3
  Thyroid stimulating hormone 4.5 μU/mL
  Urinalysis:
  Glucose negative
  Protein +++
  Ketones negative
  Nitrites negative
  RBCs negative
  Casts +++
  A renal biopsy is performed which reveals findings consistent with lupus nephritis. Which of the following is the next best step in treatment of this patient?? 
  {'A': 'Corticosteroids', 'B': 'Azathioprine', 'C': 'Cyclosporine', 'D': 'Mycophenolic acid', 'E': 'Cyclophosphamide'},