Ch. 13 ANEMIA Flashcards
What is the definition of anemia?
an abnormally low hemoglobin level, number of circulating red blood cells, or both, resulting in diminished oxygen-carrying capacity of the blood.
What are the causes of anemia?
Blood loss
Destruction of RBCs (hemolysis) faster than they can be replaced
Impaired RBC production
- – lack of nutritional elements
- – bone marrow failure
How is anemia classified?
Based of etiology (such as iron-deficient or hemolytic anemia)
Based morphology
- MCV, MCH, and MCHC values
- Size (macrocytic, microcytic, normocytic)
- Hemoglobin content (normochromic and hypochromic)
What is anisocytosis?
Red cells are present in various sizes
What is poikilocytosis?
Red cells are present in various shapes
What does microcytic mean and what is it associated with?
Smaller than normal. (morphologic)
associated with abnormal hemoglobin production.
What does normocytic mean and what is it associated with?
normal size
associated with decreased RBC production or shortened RBC life span
What does macrocytic mean and what is it associated with?
Larger than normal.
associated with abnormal erythrocyte maturation (large number of immature “blast” cells)
Why would someone have microcytic cells?
Not enough building blocks or a bone marrow issue.
Why would someone have normocytic anemia?
renal failure (decreased EPO)
spleen issue destroying RBCs too early
What would the morphology and hemoglobin content be in iron-deficiency anemia? What color would they be?
They would be microcytic and hypochromic and pale red in color.
What would the morphology of megaloblastic anemia be? What about their shape?
They would be macrocytic and present with poikilocytosis.
What are the different clinical manifestations of anemia?
decreased RBC count - pallor and decreased O2 levels
Leads to:
Tissue hypoxia: Muscle weakness, fainting, angina
General adaptation syndrome (gas): vasoconstriction (pallor and sweating), tachycardia
Kidneys release erythropoietin: Bone marrow produces more RBCs: Bone marrow expands: Bone pain and sternal pain
What is hemolytic anemia?
This is anemia caused by the premmature destruction of RBCs
What does hemolytic anemia cause?
retention of iron and other products of hemoglobin (can lead to a buildup of bilirubin and cause jaundice)
Marked increase in erythropoiesis
What do the cells of hemolytic anemia look like?
normocytic and normochromic
What are the signs and symptoms of hemolytic anemia?
easy fatigability, dyspnea, and other signs of impaired O2 transport
Also may cause jaundice by a rise in serum bilirubin
What are some of the intrinsic and extrinsic causes of hemolytic anemia?
Intrinsic: defect of RBC membrane, various hemoglobinopathies, inherited enzyme defects
Extrinsic: drugs, bacteria, chemical toxins, antibodies, physical trauma
What are the different types of hemolytic anemias and their causes?
Membrane disorders: hereditary spherocytosis (no biconcavity), and the acquired hemolytic anemias and hemolytic disease of the newborn.
Hemoglobinopathies: Sickle cell disease, Thalassemia (alpha and beta)
G6PD deficiency
What is sickle cell disease?
A point mutation in the beta chains of the hemoglobin that, when is deoxygenated, makes them link together to form a long protein rod that gives the cell a sickle shape.
Why is a newborn protected from sickle cell disease?
Because fetal hemoglobin doesn’t have beta chains, they have gamma chains in their hemoglobin until their body makes adult hemoglobin. (usually have all adult hemoglobin after 120 days)
What does it mean that sickle cell disease is an autosomal recessive trait?
This means that if mom is a carrier and dad is a carrier then there is a 25% chance that the child will have no disease, 25% chance it will have the disease, and a 50% chance that it will be a carrier with no symptoms.
What is the Hb S (beta mutated hemoglobin) sensitive to?
the oxygen content of the RBC
What can the sickling of the cells cause?
clumping inside the vessels => obstruction of microcirculation=> tissue hypoxia
Is sickling reversible?
YES, it is initially reversible. BUT repeated sickling episodes can lead it to be permanent.
What are some of the precipitating factors of cell sickling?
Cold, stress, physical exertion, hypoxia, dehydration, infection, acidosis