A 13-YEAR-OLD girl was admitted because of fever, dyspnea, chest pain, and cough. Three days prior to admission, a moderately sore throat, anorexia, dry cough, and weakness had developed.
On admission, her temperature was 38°C; heart rate, 152 beats/min; respirations, 44 breaths per minute; and blood pressure, 110/70 mm Hg. She was in moderate respiratory distress. There was cyanosis of the lips. Oropharynx and the tonsils were moderately hyperemic. Diminution of bronchial breath sounds over the right middle and lower zones was noted, and crepitant rales were heard over the lung fields. Results of the remainder of the physical examination were not remarkable.
The hemoglobin level was 129.5 g/L; hematocrit, 0.40; and white blood cell count, 1.6× 109/L, with 0.7 lymphocytes, 0.2 polymorphonuclear cells, 0.08 immature forms, rare atypical lymphocytes, and no toxic granulation. Thrombocytes were abundant; erythrocytes were normochromic and normocytic. A chest radiograph demonstrated disseminated patchy