Macrocytic Anemias

Question 1

Define Macrocytic Anemia

Answer 1

disorders in which there is an increase in the average size of the erythrocytes in peripheral blood

In most cases the amt of hgb in the enlarged cell is increased proportionately with the volume therefore the concentration of Hgb inside cell is normal

MCV ↑

MCH ↑

MCHC Normal

Question 2

Classification of Macrocytic Anemias

Answer 2

1. The Megaloblastic Anemias
2. Non Megaloblastic Anemias

Question 3

List 5 causes of megaloblastic anemias

Answer 3

1. Vit B12 Deficiency
2. Folic Acid Deficiency
3. Inherited Forms
4. Drug induced Disorders
5. Erythroleukemia

Question 4

List 3 causes of Non-Megaloblastic Macrocytic Anemias

Answer 4

1. Reticulocytosis
2. Liver Disease
3. Abnormal Marrow Function
4. Others

Question 5

Define Megaloblastic Anemia

Answer 5

an uncommon group of anemias characterized by a macrocytic and usually normochromic anemia of peripheral blood and a megaloblastic bone marrow

Question 6

Etiology of Megaloblastic Anemia

Answer 6

impaired DNA synthesis in the differentiating cells of the erythroid series that produces nuclear/cytoplasmic asynchrony in erythroblasts

i.e. the nucleus maturation lags behind the cytoplasm

This affects all cells with rapid turnover: neuts and plts, epidermal cells and GI mucosal cells etc.

Question 7

Causes of the megaloblastic anemia

Answer 7

ineffective erythropoiesis

shortened life-span of circulating RBC

Slowed erythropoiesis

Question 8

Clincal Findings of Megaloblastic Anemias

Answer 8

Mild jaundice from increased ERC turnover

Purpura from thrombocytopenia

Glossitis (enlarged, beefy red sore tongue)

Question 9

Major forms of Megaloblastic Anemias

Answer 9

Vitamin B12 Deficiency

Folic Acid Deficiency Anemia

Question 10

Peripheral Blood Findings in Megaloblastic Anemias

Answer 10

Peripheral Blood

1. Hgb ↓
2. Hct ↓
3. RBC Count ↓
4. RBC Indices MCV ↑ MCH ↑ MCHC N
5. RDW ↑
6. RBC Morphology: mild cases: oval macrocytes. Severe cases: also have HJ bodies, baso stippling, rarely Cabot Rings, and rarely megaloblasts
7. Retic count: ↓ due to ineffective erythropoiesis
8. WBC Count/ Morph: ↓ esp neuts, hypersegmented neuts, and rare giant bands
9. Plt Count/ Morph: decreased and pleomorphic

Bone Marrow

1. Cellularity hypercellular or normocellular
2. Erythroid cells: up to 50% megaloblasts also showing nuclear fragmentation and Howell Jolly bodies
3. Leukocytes: ↓ in #’s but increased in size esp. neutrophil series
4. Throbocytes series: ↓ in #’s but increased in size. Giant megakaryocytes

Question 11

Bone Marrow findings in Megaloblastic Anemia

Answer 11

Bone Marrow

1. Cellularity hypercellular or normocellular
2. Erythroid cells: up to 50% megaloblasts also showing nuclear fragmentation and Howell Jolly bodies
3. Leukocytes: ↓ in #’s but increased in size esp. neutrophil serie
4. Throbocytes series: ↓ in #’s but increased in size. Giant megakaryocytes

Question 12

Composition of Howell-Jolly Bodies

Answer 12

leftover DNA in the cell

Question 13

Compositiion of Basophillic Stippling

Answer 13

aggregated and stained RNA in the cell

Question 14

Cabot Ring composition

Answer 14

remaining nuclear membrane-fine and lightly stained