Overview of Decreased Erythropoiesis

Anemia, a decrease in the number of red blood cells (RBCs), hemoglobin (Hb) content, or hematocrit (Hct), can result from decreased RBC production Red Blood Cell Production Red blood cell (RBC) production (erythropoiesis) takes place in the bone marrow under the control of the hormone erythropoietin (EPO). Juxtaglomerular cells in the kidney produce erythropoietin... read more (erythropoiesis), increased RBC destruction, blood loss, or a combination of these factors. (See also Approach to the Patient with Anemia Evaluation of Anemia Anemia is a decrease in the number of red blood cells (RBCs) as measured by the red cell count, the hematocrit, or the red cell hemoglobin content. In men, anemia is defined as any of the following... read more .)

Anemias due to decreased erythropoiesis (termed hypoproliferative anemias) are recognized by a reticulocyte count that is inappropriately low for the degree of the anemia.

The RBC indices Testing Anemia is a decrease in the number of red blood cells (RBCs) as measured by the red cell count, the hematocrit, or the red cell hemoglobin content. In men, anemia is defined as any of the following... read more , mainly the mean corpuscular volume (MCV), can narrow the differential diagnosis of deficient erythropoiesis and help determine what further testing is necessary.

Microcytic anemias result from deficient or defective heme or globin synthesis. Microcytic, hypoproliferative anemias include

Patients with a microcytic anemia typically require evaluation of iron stores Testing Anemia is a decrease in the number of red blood cells (RBCs) as measured by the red cell count, the hematocrit, or the red cell hemoglobin content. In men, anemia is defined as any of the following... read more .

Normocytic anemias are characterized by a normal MCV (80 to 100 fL) and normochromic indices. The two most common causes are

Acquired primary bone marrow disorders such as aplastic anemia Aplastic Anemia Aplastic anemia is a disorder of the hematopoietic stem cell that results in a loss of blood cell precursors, hypoplasia or aplasia of bone marrow, and cytopenias in two or more cell lines ... read more , pure red cell aplasia Pure Red Blood Cell Aplasia Acquired pure red blood cell aplasia is a disorder of erythroid precursors that results in an isolated normocytic anemia. White blood cells and platelets are not affected. Symptoms result from... read more , and myelodysplastic syndrome Myelodysplastic Syndrome (MDS) The myelodysplastic syndrome (MDS) is group of clonal hematopoietic stem cell disorders typified by peripheral cytopenia, dysplastic hematopoietic progenitors, a hypercellular or hypocellular... read more (MDS) can also manifest with a normocytic anemia.

Macrocytic anemias can be caused by impaired DNA synthesis leading to megaloblastosis, as occurs with

Other causes of macrocytic anemia include

Some patients with hypothyroidism Hypothyroidism Hypothyroidism is thyroid hormone deficiency. Symptoms include cold intolerance, fatigue, and weight gain. Signs may include a typical facial appearance, hoarse slow speech, and dry skin. Diagnosis... read more have macrocytic RBC indices, including some without anemia.

Anemias can have variable findings on the peripheral smear Peripheral smear Anemia is a decrease in the number of red blood cells (RBCs) as measured by the red cell count, the hematocrit, or the red cell hemoglobin content. In men, anemia is defined as any of the following... read more . The anemia of chronic disease Anemia of Chronic Disease The anemia of chronic disease is a multifactorial anemia. Diagnosis generally requires the presence of a chronic inflammatory condition, such as infection, autoimmune disease, kidney disease... read more may be microcytic or normocytic. Anemias due to myelodysplastic syndromes Myelodysplastic Syndrome (MDS) The myelodysplastic syndrome (MDS) is group of clonal hematopoietic stem cell disorders typified by peripheral cytopenia, dysplastic hematopoietic progenitors, a hypercellular or hypocellular... read more may be normocytic, macrocytic, or even microcytic. Anemias due to endocrine disorders (such as hypothyroidism Hypothyroidism Hypothyroidism is thyroid hormone deficiency. Symptoms include cold intolerance, fatigue, and weight gain. Signs may include a typical facial appearance, hoarse slow speech, and dry skin. Diagnosis... read more ) or elemental deficiencies (eg, copper deficiency Acquired Copper Deficiency Copper is a component of many body proteins; almost all of the body’s copper is bound to copper proteins. Copper deficiency may be acquired or inherited. (See also Overview of Mineral Deficiency... read more , zinc deficiency Zinc Deficiency Zinc (Zn) is contained mainly in bones, teeth, hair, skin, liver, muscle, leukocytes, and testes. Zinc is a component of several hundred enzymes, including many nicotinamide adenine dinucleotide... read more ) can have variable manifestations, including a normocytic or macrocytic anemia.

Treatment of deficient RBC production depends on the cause.