Microcytic Anemia Flashcards
What causes red cells to be microcytic
When there is a problem producing hemoglobin. So when red cells come out of the bone marrow with decreased hemoglobin in each cell that usually leads to small red cells and therefore a microcytic anemia
Usually due to low hemoglobin in red cells
Usually associated with low MCH and MCHC
Low hemoglobin show hypo-chromic RBCs on smear
Low hemoglobin leads to low reticulocyte production (because reticulocytes contain hemoglobin)
What type of anemia could this be
Microcytic anemia
How do hypochromic red cells look like on blood smear
Small in size and have a a lot of paleness at their center
Loss of which components could lead to a microcytic anemia
Loss of iron
Loss of heme (lead, sideroblastic anemia)
Loss of globin chains (thalassemia)
What is the intracellular storage form of iron called
Ferritin
Where is iron stored in the body
Macrophages of liver and bone
The amount of transferrin goes up when the the iron stores in the body are low. Why
The body is producing more transferrin so it can be available to transport whatever iron is around to the places where it’s needed
What is the transport protein of iron
Transferrin
When the body is depleted of iron, ferritin stores are
Low
What are some iron measurements
Serum iron (iron level in the serum)
Total iron binding capacity (amount of transferrin in serum)
Serum ferrritin (amount of storage iron found in the serum)
% saturation (amount of transferrin bound to Fe - iron level/total iron binding capacity)
Explain what occurs in the body in the setting of iron loss
Ferritin decreases followed by an increase in transferrin (TIBC)(body seeks more iron to respond to low iron stores). Then serum iron decreases leading to a low % saturation of iron (low iron levels/high TIBC)
Normal distribution of red cell distribution is
Relatively narrow
Gets wider with iron deficiency anemia
Why is the red cell distribution width wider with iron deficiency anemia
Sometimes the bone marrow is able to to find enough iron to make cells of normal size and other times it can’t find enough so it makes small cells. So as a result you get a wider distribution of cell sizes
When there is a microcytic anemia with a normal red cell distribution width (RDW), what condition could be considered
Thalassemia
What spectrum is useful in distinguishing iron deficiency anemia from thalassemia
Red cell distribution width (RDW)
What are the most common causes of microcytic anemia
Iron deficiency and thalassemia
Spectrum of RBC size
Often increase in iron deficiency
Normal RDW makes iron deficiency unlikely
What could this be
Red cell distribution width
Low RBC/Hgb/Hct
Low MCV (small cells)
Hypochromic (low hemoglobin)
Low MCV/MCH/MCHC
Initially may be normocytic
Low reticulocyte count
What condition might this be
Iron deficiency anemia
Which type of iron in the body is poorly absorbed
Fe3+
Which type of iron in the body is easily absorbed
Heme iron (as part of a heme molecule)
Fe2+
What vitamin helps in converting Fe3+ to Fe2+ to make it easier to absorb iron that’s not in heme
Vitamin C
What are the underlying mechanisms of iron deficiency
Lack of iron uptake by the gut
Loss of iron (usually due to chronic blood loss)
Loss of acid production in the stomach could lead to iron deficiency. How
Loss of acid production in the stomach causes dietary iron to convert to the Fe3+ which the gut finds a hard time absorbing
What conditions could subject patients to loss of production of acid
Proton pump inhibitors
Celiac disease
Status post gastrectomy
