Splenic Sequestration and Suspected Transient Aplastic Crisis in Sickle-Cell SC/Hemoglobin-G Disease in an Adult: A Case Report.

Acute Splenic Sequestration Crisis (ASSC) and Transient Aplastic Crisis (TAC) are severe, but distinct, hematologic complications of sickle cell disease (SCD). ASSC typically presents with acute splenomegaly and anemia due to red blood cell (RBC) pooling, while TAC, often secondary to Parvovirus B19 infection, results in a sudden halt in erythropoiesis and reticulocytopenia. The concurrence of these two conditions is rare, particularly in adults and non-Hb-SS genotypes. We describe a 36-year-old woman with Hb-SC and Hb-G Philadelphia variant SCD who presented with non-specific symptoms who was found to have marked splenomegaly and laboratory findings of severe anemia (hemoglobin 3.8 g/dL), thrombocytopenia, and reticulocytopenia. These combined findings raised concern for ASSC with suspected TAC, especially in light of her positive Parvovirus B19 IgM antibodies. We describe the importance of having a structured and precise diagnostic work-up to elucidate differences between the two conditions in the absence of a bone marrow biopsy, and the rarity of concurrent ASSC with presumed TAC in a patient with Hb-SC SCD. Our case highlights that early recognition of overlapping sickle cell complications despite a bone marrow biopsy is critical as it led to timely diagnosis, optimized management strategies, and reduced morbidity.