challenging case ....who will catch it

A 38-year-old man with advanced AIDS is hospitalized for respiratory distress, fever and hypoxemia. Community-acquired pneumonia is diagnosed, and the patient initially improves after initiation of levofloxacin therapy. Over the next 2 weeks, his creatinine level progressively increases from 0.8 mg/dL (70.74 µmol/L) to 3.7 mg/dL (327.15 µmol/L). Over the past 3 days, his urine output has decreased to 500 mL/24 h. He has previously been treated for pulmonary tuberculosis and polysubstance abuse.

On physical examination, temperature is 37.8 °C (100.1 °F), pulse rate is 110 beats/min and blood pressure is 110/60 mm Hg. He is thin and in mild respiratory distress. There are scattered petechiae and ecchymoses across his skin, and he has spontaneous gingival bleeding. Pulmonary examination reveals crackles at the right base. The PMI is laterally displaced. The abdomen is soft without organomegaly. There is no edema. On neurologic examination, he is lethargic and able to answer only simple questions.

Laboratory findings are as follows: hemoglobin level, 7.6 g/dL (76 g/L); leukocyte count, 9400 cells/µL (9.4 × 109 cells/L); platelet count, 18,000 cells/µL (18 × 109 cells/L); blood urea nitrogen level, 75 mg/dL (26.78 mmol/L); creatinine level, 3.5 mg/dL (309.47 µmol/L); sodium level, 129 mEq/L (129 mmol/L); potassium level, 3.2 mEq/L (3.2 mmol/L); chloride level, 88 mEq/L (88 mmol/L); bicarbonate level, 30 mEq/L (30 mmol/L); lactate dehydrogenase level, 7483 U/L (124.74 µkat/L); and urinalysis results of 1+ leukocyte esterase, 1+ protein, trace blood and 5 to 10 dysmorphic erythrocytes per high-power field.