Michelle Christina Johansen, MD
Extensive exposure to Sickle cell Disease (SCD) is not a common occurrence for the general adult neurologist, but cerebrovascular specialists must treat SCD patients appropriately and know how to respond when they present with an ischemic stroke. Literature dictates that exchange transfusions are essential in preventing both recurrent and first ever stroke when paired with transcranial doppler in the pediatric population. For the adult patient however, there is little data to guide treatment. What is the best way to treat these patients? What are the common presenting symptoms?
26 children and 29 adults (>18yo) with a first ever ischemic stroke were identified from a prospective cohort (1985-2014) based at a sickle cell referral center in France. The aim of the study was to assess characteristics of first ischemic stroke in adults and compare those characteristics to child patients. Mechanisms of the ischemic stroke was determined by consensus meeting held with a neurologist, internist, neuroradiologist and pediatrician when appropriate. The patients were grouped according to prespecified etiologies: Vasculopathy, Cardioembolism, other defined causes and undetermined. Stroke recurrence was also monitored. Of the 29 adult patients identified, 2 suffered a fatal stroke, 25 were homozygous for SC, 3 were heterozygous and 1 had S-β0 thalassemia. All 26 children were homozygous.
Calvet et al. found that vasculopathy was more frequently the cause of ischemic stroke in SCD children (24/26) than adults (12/29). The remaining adults had cardioembolism (7), antiphospholipid syndrome (1), cocaine (1) and undetermined (8) as mechanisms. Both adults and children with vasculopathy as an etiology were treated with exchange transfusion yet adults still had a higher risk of recurrent stroke (23.1%) when compared to the children (1 occurrence).
The results of this study are limited by referral bias as well as the small number of patients in each cohort but the authors are to be applauded for their important investigation into the presenting characteristics of adult patients with sickle cell. Despite the limitations, what conclusions can the practicing neurologist draw? Vasculopathy, as would be expected, remains the leading cause of ischemic stroke in SC adults. As the authors point out in their discussion, the physician must avoid tunnel vision when treating these patients and consider other, more frequently encountered etiologies. What role does exchange transfusion play in the adult? It is important to note that all children were homozygous for SC while 4 adult patients were not. How does this influence the results? Should the SCD clinical phenotype play a more important role in guiding our acute stroke care? There are many remaining unanswered questions but larger epidemiologic cohort studies should in the future more accurately guide our care.