Abnormal increase in the number of RBCs is known as:
**Core Concept**
Polycythemia vera is a myeloproliferative disorder characterized by the abnormal increase in the number of red blood cells (RBCs) in the blood. This condition is caused by the overproduction of erythropoietin (EPO) or other growth factors that stimulate the bone marrow to produce RBCs.
**Why the Correct Answer is Right**
Polycythemia vera is a type of polycythemia, which is a hematological disorder characterized by an increase in the total blood volume, leading to thickening of the blood. This condition can cause increased blood viscosity, which may lead to thrombotic events. The overproduction of RBCs is often accompanied by an increase in the production of other blood cells, including platelets and white blood cells.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the question.
**Option B:** This is a type of anemia, not polycythemia.
**Option C:** This is a type of anemia characterized by a decrease in the number of RBCs.
**Clinical Pearl / High-Yield Fact**
Polycythemia vera can be associated with an increased risk of thrombotic events, such as deep vein thrombosis and stroke. Patients with this condition should be monitored regularly for signs of thrombosis and should be treated with anticoagulants if necessary.
**Correct Answer:** C.