Sickle cell anemia is usually associated with all, except:
**Core Concept**
Sickle cell anemia is a genetic disorder characterized by the production of abnormal hemoglobin, leading to the formation of sickle-shaped red blood cells. This condition is caused by a point mutation in the HBB gene, resulting in the substitution of glutamic acid with valine at position 6 of the beta-globin chain.
**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of sickle cell anemia. The disorder is characterized by the polymerization of deoxyhemoglobin S, which causes red blood cells to become rigid and assume a sickle shape. This process is triggered by low oxygen levels, dehydration, and other factors that increase the concentration of deoxyhemoglobin S. The polymerization of deoxyhemoglobin S is facilitated by the presence of high concentrations of sodium ions, which can be seen in conditions such as hypernatremia.
**Why Each Wrong Option is Incorrect**
**Option A:** Anemia is a hallmark of sickle cell disease, and patients often present with hemolytic anemia, which is characterized by the premature destruction of red blood cells.
**Option B:** Sickle cell anemia is indeed associated with increased susceptibility to infections, particularly those caused by encapsulated organisms such as Streptococcus pneumoniae.
**Option C:** Sickle cell anemia can cause vaso-occlusive crises, which occur when sickled red blood cells obstruct blood flow in small vessels, leading to tissue ischemia and infarction.
**Clinical Pearl / High-Yield Fact**
Patients with sickle cell anemia are also at increased risk of developing priapism, a condition characterized by prolonged and painful erections.
**Correct Answer: D.**