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Wednesday, May 22, 2013
Sickle Cell Anemia
Sickle Cell And Stroke
Why do strokes occur in people with sickle cell anemia and how high is the risk? Is there any way to prevent these strokes?
Strokes in sickle cell patients can be due to:
- Lack of blood supply to the brain.
- Hemorrage into the brain.
These strokes can be:
- Overtly symptomatic (i.e. have definite signs associated with the stroke)
- Silent (i.e. subtle with no definitely define-able signs that are apparent to the patient)
Strokes can occur in sickle cell patients due to one of many causes, which may include:
Sickling of Red Blood Cells in blood vessels supplying the brain and causing obstruction to blood flow in the brain.
Changes in Red Cell Membranes that can cause young Red Cells to stick to blood vessel walls trapping dense sickle cells and reducing blood flow to the brain.
Damage to the internal lining of blood vessels (endothelium), with activation of clotting inside blood vessels leading to the formation of a blood clot inside blood vessels supplying the brain, and compromising blood flow to the brain.
Hemorrhages can also occur in fragile brain blood vessels due to altered blood pressures in sickle cell patients related to profound anemia and cause a stroke.
Sometimes with a severe pain crisis (extensively involving the bone marrow) fat globules can circulate in the blood and lodge in the brain causing a stroke.
Risk of stroke in Sickle Cell patients
- The risk of stroke in sickle cell patients may be as high as 25%.
- Silent Strokes in Sickle Cell Disease may be upto 10 to 20%.
- The percentage of risk may be related to the kind of SCD for eg in Hb SC disease the risk is about 3 % for infarctive strokes.
Treatment and prevention of strokes
The mainstay of prevention of strokes in high risk patient and in the treatment and prevention of subsequent strokes in patients who have already suffered a stroke are regular blood transfusions. The goal of treatment is to lower sickle hemoglobin to < 30%
I hope these answer some of your questions. The field of stroke its complications and treatment in sickle cell disease especially in the adult patient is still evolving. Many questions do not have definite proven answers. Investigational drugs that help to dilute out sickle cell hemoglobin may be useful in the future, as may bone marrow and stem cell transplantation.
Zahida Yasin, MD
Assistant Professor of Medicine
Director-Adult Sickle Cell Program
College of Medicine
University of Cincinnati