Sickle Cell Anemia

Question 1

What is Sickle cell anemia?

Answer 1

Severe hemolytic anemia that results from inheritance of the sickle hemoglobin gene (HbS)

Question 2

Pathophysiology

Answer 2

Exposure
The sickle hemoglobin acquires a crystal-like formation when exposed to low oxygen tension.

Change in the shape.
The oxygen level in venous blood can be low enough to cause the erythrocyte to lose its round, pliable, biconcave disk shape.

Adherence.
These long, rigid erythrocytes can adhere to the endothelium of small vessels; when they adhere to each other, blood flow to a region or organ is reduced.

Reversion.
If the erythrocyte is again exposed to adequate amounts of oxygen before the membrane becomes too rigid, it can revert to normal shape.

Question 3

Clinical manifestations

Answer 3

Anemia is always present; usually, hemoglobin values are 7 to 10g/dl.

Jaundice is characteristic and usually obvious in the sclerae.

Dysrhythmias and heart failure may occur in adults.

Enlargement of the bones. The bone marrow expands in childhood in a compensatory effort to offset anemia, sometimes leading to enlargement of the bones of the face and skull.