A 56-year-old woman is referred to you for an evaluation of dyspnea and chest pain of 6 weeks in duration. The chest pain is nonpleuritic, nonexertional, and located along the lower right lateral chest cage. She has no fever, cough, or chills. During the past few weeks, she has been experiencing constant low back pain. The patient underwent right mastectomy 4 years ago because of carcinoma of the breast with metastatic involvement of the right axillary lymph nodes. She received radiotherapy followed by chemotherapy for 24 months. Examination now shows diminished breath sounds in the right lower lung field. Results of the remainder of the examination are unremarkable. A chest radiograph suggests a moderate right pleural effusion. Which one of the following is most likely to be helpful in



confirming the suspected diagnosis? 

A 20-year-old male military recruit returns home from several weeks of summer training in boot camp. He comes to your office the following day with a 12-day history of fever (38°C), coryza, pharyngitis, and cough. Physical examination discloses a bullous lesion over the right tympanic membrane and scat- tered crackles in both lung fields. Blood cell count shows mild thrombocytopenia. A chest radiograph shows patchy alveolar- interstitial infiltrates in both lungs. Which one of the following is the best treatment for this patient? 

A 49-year-old male executive comes to your office with a 6- month history of cough, shortness of breath, and chest tightness soon after substantial exertion. He notices these symptoms soon after he finishes a game of racquetball. He is a nonsmoker and has no risk factors for coronary artery disease. Results of physical examination in your office are normal. His weight is normal for his height. The chest radiograph is normal. A treadmill test for ischemic heart disease is negative. Which one of the following diagnostic tests is indicated? 

A 43-year-old asymptomatic man has chronic hepatitis C. Therapy for 12 months with a combination of interferon and ribavirin failed to clear the virus. Laboratory results are notable for an alanine aminotransferase value of 65 U/L and normal values for bilirubin, albumin, and prothrombin time. A liver biopsy shows a mild lymphocytic portal infiltrate but no fibrosis. Which one of the following statements about this patient is true? 

A 45-year-old man comes to your clinic for evaluation of new-onset hypertension. Blood pressures obtained elsewhere were 146 to 160/84 to 100 mm Hg, and heart rates ranged from 82 to 96 beats per minute. He does not smoke or drink alcohol. He has no history of diabetes mellitus. His family history is positive for hypertension in his father. On physical examination, his blood pressure is 144/86 mm Hg and body mass index 32 kg/m2. Results of the remainder of the examination are unremarkable. Laboratory test values are as follows: serum sodium 142 mEq/L, serum potassium 4.2 mEq/L, serum chloride 104 mEq/ L, serum bicarbonate 24 mEq/L, glucose 116 mg/dL, blood urea nitrogen 14 mg/dL, serum creatinine 1.0 mg/dL. Which one of the following is the best initial test in the evaluation of this patient?