Which of the following anemias is classified as normocytic and hyperproliferative?

Explanation

## Normocytic Hyperproliferative Anemias **Key Point:** Normocytic anemias with elevated reticulocyte counts (hyperproliferative) indicate appropriate bone marrow response to RBC loss or destruction. The marrow is functioning normally but working overtime. ### Classification of Normocytic Anemias | Anemia Type | Reticulocyte Count | Mechanism | Examples | | --- | --- | --- | --- | | **Hyperproliferative (High Retic)** | >2% | Appropriate marrow response to loss/destruction | Acute hemorrhage, hemolytic anemia, hemoglobinopathies | | **Hypoproliferative (Low Retic)** | <2% | Inadequate marrow response despite anemia | Aplastic anemia, chronic kidney disease, anemia of chronic disease (late), mixed deficiencies | **High-Yield:** The reticulocyte count is the key discriminator within the normocytic category. A high reticulocyte count indicates the marrow is responding appropriately to RBC loss or destruction; a low count suggests a primary marrow problem. ### Acute Hemorrhage: The Prototype **Clinical Pearl:** Acute hemorrhage is the classic normocytic, hyperproliferative anemia: - **MCV:** Normal (80–100 fL) — RBCs are normal size - **Reticulocyte count:** Elevated (>2%, often >5%) within 3–5 days - **Mechanism:** Bone marrow responds appropriately to acute blood loss by releasing immature RBCs - **Timeline:** Reticulocytosis peaks at 5–7 days post-hemorrhage ### Why Other Options Are Wrong - **Vitamin B12 deficiency:** Macrocytic (MCV >100 fL) due to impaired DNA synthesis - **Chronic kidney disease:** Normocytic but **hypoproliferative** (low reticulocytes) due to erythropoietin deficiency - **Folate deficiency:** Macrocytic (MCV >100 fL) due to impaired DNA synthesis