Two days later, a sharp left upper quadrant pain with increasing shortness of breath developed. Vital signs were as follows: BP, 124/60 mm Hg; heart rate, 136 beats/min; respiratory rate, 26 breaths/min; temperature, 39.2°C; and arterial oxygen saturation, 85% on room air. Examination of the chest revealed bilateral basal crackles. The abdomen was tender to palpation on the left upper quadrant. The spleen was palpable 4 cm below the left costal margin. Arterial blood gas analysis on room air showed a pH of 7.47; Po2, 47 mm Hg; and Pco2, 40 mm Hg, with a bicarbonate level of 28 mEq/L. CT scans of the chest (Fig 2
) and abdomen (Fig 3
) were performed. WBC count was 21,600/μL; hematocrit, 19%; hemoglobin, 7 g/dL; platelet count, 61,000/μL; reticulocyte count, 10%; and lactate dehydrogenase, 2,485 U/L. Blood culture findings remained sterile.