Acute splenic sequestration in hemoglobin sickle O-Arab disease.

A white girl with sickle O-Arab disease (Hb S/O-Arab) had three separate episodes of acute splenic sequestration at 8, 12, and 15 months of age with hemoglobin levels falling to 3.9, 2.8, and 4.2 g/dl, respectively. Functional hyposplenism was suggested by the radionucleotide spleen scan. Following splenectomy her hemoglobin stabilized in the range of 0.7--8.5 g/dl. Life-threatening episodes of splenic sequestration, pneumococcal infections and osteomyelitis may occur in both Hb S/O-Arab and homozygous sickle cell diseases.