Sickle cell anemia causes tissue hypoxia and pain due to which mechanism?

Sickle cell anemia causes tissue hypoxia and pain due to which mechanism?

• A. Decreased RBC production
• B. Obstruction of blood flow from sickled cells
• C. Excessive bleeding
• D. High bilirubin causing jaundice

Answer: (B)

When red blood cells sickle, hemoglobin S polymerizes in low oxygen, causing the cells to become rigid and crescent-shaped. These stiff, sticky cells lose their ability to deform and often occlude small vessels, blocking blood flow. That interruption reduces oxygen delivery to tissues, leading to ischemia and the painful crises seen in sickle cell anemia. The other options describe related features (decreased RBC production causing anemia, excessive bleeding, or bilirubin from hemolysis) but they do not explain the acute vaso-occlusion that drives tissue hypoxia and pain.

When red blood cells sickle, hemoglobin S polymerizes in low oxygen, causing the cells to become rigid and crescent-shaped. These stiff, sticky cells lose their ability to deform and often occlude small vessels, blocking blood flow. That interruption reduces oxygen delivery to tissues, leading to ischemia and the painful crises seen in sickle cell anemia. The other options describe related features (decreased RBC production causing anemia, excessive bleeding, or bilirubin from hemolysis) but they do not explain the acute vaso-occlusion that drives tissue hypoxia and pain.