question: Q:A 50-year-old man is brought to the emergency department by his wife because of lethargy and confusion for the past 24 hours. He has also had a productive cough for the past year and has had a 10-kg (22-lb) weight loss over the past 6 months. He has a history of multiple sclerosis and has not had an acute exacerbation in over 10 years. For the past 30 years, he has smoked 2 packs of cigarettes daily. He drinks 2 beers every day after work. His temperature is 37.0°C (98.6°F), pulse is 90/min, blood pressure is 130/90 mm Hg, and respirations are 22/min. On examination, the patient appears lethargic and cannot state his name or his location. Physical examination reveals scattered wheezing bilaterally. Deep tendon reflexes cannot be elicited. Laboratory studies show:
  Serum
  Na+ 115 mEq/L
  K+ 4.5 mEq/L
  HCO3- 22 mEq/L
  Glucose 70 mg/dL
  Blood urea nitrogen 8 mg/dL
  Urine osmolality 450 mOsmol/kg H2O
  Urine sodium 70 mEq/L
  An x-ray of the chest reveals a central lung mass. Which of the following is the next best step in management?"? 
  {'A': 'Order CT scan of the chest', 'B': 'Administer furosemide', 'C': 'Administer hypertonic saline', 'D': 'Administer demeclocycline', 'E': 'Administer conivaptan'},