Scanning electron microscopy of the spleen in a case of sickle cell anemia.

We report the case of a 5 1/2-year-old Congolese girl with homozygous sickle cell anemia and hereditary persistence of fetal hemoglobin (Hemoglobin S 88%, Hemoglobin A2 2%, Hemoglobin F 10%). She presented marked enlargement of the spleen, descending into the left iliac fossa and producing significant hypersplenism with thrombocytopenia as low as 60,000/mm3. Additional findings included an increase in plasma volume to 90% greater than normal, with elevation of both cardiac output (determined by radiolabelled albumin) to 4 l/min and cardiac index to 6.25 l/min. Splenectomy became clinically necessary after the occurrence of two successive episodes of acute splenic sequestration characterized by a rapid, painful splenic enlargement associated with a poorly tolerated fall in hemoglobin to 4 gm/dl. Preparation for surgery included exchange transfusion with slow removal of 20 ml/kg of the patient's blood and replacement with type specific HbAA blood at 15 ml/kg. Following the exchange transfusion, the hemoglobin level rose from 8 to 12 gms/dl and the percentage of hemoglobin S fell from 89% to 36%. The patient did well following splenectomy and 8 weeks later repeat hematologic values showed a hemoglobin of 10.1 gms/dl, reticulocytes of 500,000/mm3, platelet count of 254,000/mm3 and white count of 13,200/mm3.