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Diagnosis & Discussion


Hyperhemolysis Syndrome in Sickle Cell Disease


Hyperhemolysis syndrome (HS) is a rare but serious condition that can be seen in patients with sickle cell disease, among other conditions. HS is characterized by profound anemia after transfusion. Unlike delayed hemolytic transfusion reaction, in HS the post-transfusion Hb level is lower than the pre-transfusion level. Symptoms of HS often include pain and fever. Laboratory values typically show a low Hb, a decreased absolute reticulocyte count, an elevated bilirubin and lactate dehydrogenase (LDH), and hemoglobinuria.

HS may be acute or delayed. The acute form occurs within 7 days of transfusion and the DAT is usually negative in these cases. The delayed form, on the other hand, evolves more than 7 days of transfusion, often with a positive DAT. The mechanism of HS remains to be completely understood. However, multiple factors, such as bystander hemolysis, in which the host’s RBCs are destroyed in addition to the transfused RBCs, destruction by activated macrophages, and impaired erythropoiesis are thought to be involved.

Clinically, it is essential to recognize and promptly manage HS as the fatality rate is significant. When HS is suspected, further RBC transfusion should be avoided to prevent exacerbation of hemolysis. Treatment consists of steroids and IVIG. Administration of rituximab, a monoclonal antibody, or erythropoietin and therapeutic plasma exchanged may also be considered.


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2. Banks M, Shikle J. Hyperhemolysis Syndrome in Patients With Sickle Cell Disease. Arch Pathol Lab Med. 2018 Nov;142(11):1425-1427. doi: 10.5858/arpa.2017-0251-RS. PMID: 30407854.

3. Win N. Hyperhemolysis syndrome in sickle cell disease. Expert Rev Hematol. 2009 Apr;2(2):111-5. doi: 10.1586/ehm.09.2. PMID: 21083443.

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