(P-TA-9) Red cell exchange and plasma exchange in the treatment of fat embolism syndrome

Background/Case Studies: A 21-year-old female with sickle cell disease and prior sickle cell crisis was admitted to an outside hospital with pain crisis complicated by acute kidney injury and transaminitis. She was managed with IV fluid and pain control. She received 1 unit of packed red blood cells (pRBC). She was also treated for possible community-acquired pneumonia prior to transfer to our hospital.

Physical examination was unremarkable other than drowsiness, however, patient was communicative and answering questions appropriately. No sensorimotor deficits were identified.

Following transfer, the patient received 2 additional units of pRBC, with a decrease in hemoglobin S (HbS) to 30.1%. The next day, she developed acute left-sided weakness and left facial droop. Her head CT showed no abnormalities, however, a subsequent brain MRI showed innumerable tiny foci of blooming artifact most consistent with previous fat embolism to the brain.

Despite her relatively low HbS, the new neurologic symptoms and radiologic findings warranted emergent red cell exchange (RCE) for possible fat embolism syndrome.

Following the procedure, the patient was otherwise improving but continued to have somnolence out of proportion to her pain medication. After discussion with the hematology-oncology team and review of case reports, it was agreed that the potential benefits of therapeutic plasma exchange (TPE) would be pursued.

Study

Design/Methods: This is a case report. Both RCE and TPE were performed based on clinical and laboratory evaluation, including peripheral blood smear and HbS levels.

Results/Findings: Selected laboratory values include: (Table 1)

The patient tolerated RCE and TPE without adverse events. The day after TPE, her left-sided deficit was noted to be improved and she was transitioned out of intensive care.

Conclusions: FES is a high mortality complication of sickle cell disease resulting from extensive bone marrow necrosis. This diagnosis should be considered in patients with sickle cell disease (often non-homozygous) with respiratory failure, neurologic involvement, thrombocytopenia, and/or markedly elevated serum ferritin. The evidence from the literature clearly indicates that RCE can be lifesaving and should be instituted as soon as the diagnosis is suspected. Articles in the literature suggest that TPE can assist in removing proinflammatory cytokines, adhesion molecules, free hemoglobin (leading to nitric oxide depletion), arginase, procoagulant factors, and other harmful molecules. However, more study is needed to determine the role of TPE for FES patients.

Importance of research: Bone marrow necrosis with fat embolism syndrome is an underrecognized complication of sickle cell anemia and variants, particularly sickle-beta thalassemia, and hemoglobin SC disease. This condition can be rapidly fatal if not treated promptly and definitively with red cell exchange. Based upon limited data in the literature plasmapheresis in addition to red cell exchange may provide a survival/neurological recovery benefit. This is an area in great need of further study.