Macrocytic Anemia

Question 1

RBCs with increased volume, diameter, and thickness

Answer 1

macrocytes

• MCV > 100
• RBCs will be larger than the nucleus of a small lymph and may lack central pallor

Question 2

causes and mechanisms of macrocytes

Answer 2

• megaloblastic erythropoiesis
• reticulocytosis: hemolytic anemia, hemorrhage
• macronormoblastic erythropoiesis

Question 3

megaloblastic erythropoiesis

Answer 3

• abnormalities of DNA metabolism
• vitamin B12 or folate deficiency
• drugs interfering with DNA synthesis

Question 4

macronormoblastic erythropoiesis

Answer 4

• BM disorders
• lipid abnormalities (liver disease)
• alcoholism

Question 5

megaloblastic anemia

Answer 5

• impaired DNA synthesis - defective nuclear maturation (cytoplasm no affected)
• primarily caused by vit B12 and folate deficiencies

Question 6

Vit B12 and folate deficiencies symptoms

Answer 6

• anemia
• GI symptoms
• Glossitis
• neurological symptoms (for vit B12 def only)

Question 7

screening tests for megaloblastic anemia

Answer 7

• CBC: decreased Hb, pancytopenia with reticulocytopenia, high MCV, increased RDW
• peripheral blood smear: macroovalocytes, hypersegmented neutrophils, tears, schistocytes, HJ bodies, basophilic stippling

Question 8

Megaloblastoid cell maturation

Answer 8

• hypercellularity
• ineffective myelopoiesis = giant bands and metamyelocytes
• megakaryocytes may also be affecyed

Question 9

hypercellularity

Answer 9

making lots of precursor cells - filling up bone marrow but not enough good cells to go out into the body

Question 10

Development of megaloblastic anemia

Answer 10

• vit B12 or folate def
• hypersegmentation of neutrophils in the peripheral blood
• macroovalocytes in the peripheral blood
• megaloblastic changes in bone marrow
• anemia

Question 11

reticulocytosis

Answer 11

an abundance of reticulocytes

Question 12

immature RBCs that last in circulation for about 24h ours

Answer 12

reticulocytes

• higher MCV
• contain residual ribosomal RNA

Question 13

this occurs when cells are released prematurely from the BM in response to high levels of EPO

Answer 13

stress reticulocytes or shift reticulocytosis

Question 14

increased reticulocytes is seen with:

Answer 14

• hemolytic anemia
• hemorrhage
• hematinic therapy
• hypoxia

Question 15

T or F. reticulocytes can increase measured MCV

Answer 15

T!

Question 16

non-megaloblastic macrocytic anemia

Answer 16

peripheral blood smear:

• MCV 100-110 fL
• round macrocytes
• no hypersegmentation

BM

• normocellular or hypercellular
• normoblastic, not megaloblastic

Question 17

liver disease

Answer 17

• related to increased lipid deposition in the RBC membrane leading to changes in membrane rigidity and shape
• peripheral blood smear may show target cells and acanthocytes

Question 18

alcohol effects on hematopoiesis:

Answer 18

• direct toxic effect on bone marrow
• alcoholic cirrhosis leading to changes in lipid metabolism
• folate deficiency
• macrocytosis often precedes anemia

Question 19

Myelodysplastic syndromes

Answer 19

• malignancy featuring abnormal or ineffective hematopoiesis (refractory anemias)
• lots of unknowns:
  > may have dimorphic population (high RDW)
  > may have megaloblastoid cell maturation
  > may show effects in other cell lines