Chapter 68. Sickle Cell Disease
Which of the following factors can contribute to increased risk for vasoocclusion in sickle cell disease patients?
A. Decreased red blood cell (RBC) deformability
B. High RBC fetal hemoglobin (HbF) concentration
C. Low RBC adult hemoglobin (HbA) concentration
D. Rapid RBC transit through microcirculation
Option A: Correct. Decreased red cell deformity, along with slower microcirculation and cell adhesion to the vascular endothelium all contribute to vasoocclusion.
Option B: Incorrect. A high HbF concentration is protective against vasoocclusion.
Option C: Incorrect. Low HbA concentration is not likely to contribute to vasoocclusion.
Option D: Incorrect. Rapid RBC transit would not lead to increased risk for vasoocclusion.
MM is a 9-year-old boy with sickle cell disease (SCD) who has just had a stroke. He is starting to regain some motor function and is progressing well. What is the most effective measure that can be taken to prevent further strokes in MM?
A. Hydroxyurea taken daily for life
B. IV antibiotics for 10 days to prevent meningitis
C. Anticoagulant medications
D. Chronic transfusion RBC therapy for life
Option A: Incorrect. Hydroxyurea can help with other complications of SCD, but does not impact stroke recurrence.
Option B: Incorrect. Since SCD-related stroke is not infectious in origin, antibiotics do not have a role in decreasing stroke recurrence.
Option C: Incorrect. The use of anticoagulants in SCD-related stroke is not helpful since the cause is not thrombotic in nature.
Option D: Correct. Chronic transfusion of RBCs has been shown to decrease stroke recurrence from 50% to 10% over 3 years, and if therapy is discontinued the risk of recurrence increases again.
Which of the following patients with sickle cell disease is the best candidate for initiation of hydroxyurea?
A. A 6-year old with a sickle cell related stroke.
B. A 28-year old with 9 pain crises in the past 2 years.
C. A 41-year old with a history of bone infarcts and osteomyelitis.
D. A 17-year old with renal impairment and acute chest syndrome.