Normocytic Anemias

Question 1

What are microcytic anemias (MCV <80) usually due to?

Answer 1

Lack of hemoglobin production

• Iron deficiency
• Defect in heme group / protoporphyrin ring synthesis (Sideroblastic anemia)
• Defect in the heme protein itself (Thalassemias)
• Anemia of chronic disease (Can also be normocytic)

Question 2

What are normocytic anemias (MCV 80 - 99) usually due to?

Answer 2

• Anemia of chronic disease
• Paroxysmal nocturnal hemoglobinuria
• G6PD Deficiency
• Hereditary spherocytosis

Question 3

What are macrocytic anemias (MCV >100) usually due to?

Answer 3

• B₁₂ deficiency (Malnutrition, chronic gastritis, pernicious anemia)
• Folate deficiency (Malnutrition, alcoholism, chemotherapy)

Question 4

What is anemia of chronic disease?

Answer 4

Anemia due to an underlying, chronic inflammation

Question 5

What acute inflammatory product is involved in anemia of chronic disease? What is the mechanism of action?

Answer 5

Hepcidin; inflammation triggers hepcidin to decrease gut iron absorption and increase iron storage by ferritin

Question 6

What labs are associated with anemia of chronic disease?

Answer 6

Decreased iron

Increased ferritin

Decreased total iron-binding capacity / transferrin

Question 7

What are three non-infectious diseases that are commonly associated with anemia of chronic disease?

Answer 7

Kidney disease

Autoimmunity

Rheumatologic diseases

Question 8

What is the basic mechanism of paroxysmal nocturnal hemoglobinuria?

Answer 8

A defect in the PIGA gene leads to a decreased RBC ability to inhibit MAC (Membrane Attack Complex) attack by the complement cascade.

Question 9

What two RBC glycoproteins typically prevent complement MAC formation and RBC lysis?

What gene codes for these glycoproteins?

In what normocytic anemia is this gene non-functional?

Answer 9

CD55 (Decay-accelerating factor) and CD59

PIGA

Paroxysmal nocturnal hemoglobinuria