Pancytopenia and "caillary leak syndrome" with infectious mononucleosis

A 19-year-old man with documented infectious mononucleosis presented with pancytopenia and a megaloblastic bone marrow. He developed a "capillary leak syndrome" with an expanded plasma volume of 9,290 ml and normal right heart and pulmonary artery pressures. The patient had a dramatic recovery after corticosteroid therapy.