Which statement about the pathophysiology of sickle cell disease is correct?

Which statement about the pathophysiology of sickle cell disease is correct?

• A. Hyperglycemia promotes sickling
• B. Hypoxia leading to HbS polymerization
• C. Alkalosis promotes sickling
• D. Hyperthermia promotes sickling

Answer: (B)

The key idea is that sickling happens when hemoglobin S is in a deoxygenated state. When oxygen levels fall, HbS tends to polymerize into long fibers inside red blood cells, distorting the cell into a rigid, sickle shape. This polymerization is what drives vaso-occlusion and hemolysis in sickle cell disease. Reoxygenation can reverse the process because the fibers dissolve with oxygen again, but repeated cycles damage the cell membrane. So, hypoxia leading to HbS polymerization is the correct statement because it directly links the trigger (low oxygen) to the molecular change (HbS polymerization) that causes sickling. Hyperglycemia, alkalosis, or hyperthermia are not the primary drivers of HbS polymerization; acidosis and dehydration can promote sickling, whereas alkalosis and higher temperature are not the main promoting factors.

The key idea is that sickling happens when hemoglobin S is in a deoxygenated state. When oxygen levels fall, HbS tends to polymerize into long fibers inside red blood cells, distorting the cell into a rigid, sickle shape. This polymerization is what drives vaso-occlusion and hemolysis in sickle cell disease. Reoxygenation can reverse the process because the fibers dissolve with oxygen again, but repeated cycles damage the cell membrane.

So, hypoxia leading to HbS polymerization is the correct statement because it directly links the trigger (low oxygen) to the molecular change (HbS polymerization) that causes sickling. Hyperglycemia, alkalosis, or hyperthermia are not the primary drivers of HbS polymerization; acidosis and dehydration can promote sickling, whereas alkalosis and higher temperature are not the main promoting factors.