Module 4.2 Hematology Flashcards
What are the characteristics normocytic-normochromic anemias and which are the 5 types of normocytic-normochromic anemias?
These anemias are characterized by erythrocytes that are normal in size and hemoglobin content, but insufficient in number
- Aplastic anemia (damage to bone marrow erythropoiesis)
- Posthemorrhagic anemia (acute blood loss)
- Acquired hemolytic anemia (immune destruction of erythrocytes)
- Hereditary hemolytic anemia (Ex: sickle cell disease)
- Anemia of chronic inflammation (multiple causes)
What causes aplastic anemia & what signs and symptoms are associated with it?
- It is a result of depressed stem cell proliferation caused by an autoimmune disease directed against hematopoietic stem cells resulting in bone marrow aplasia.
- S/S: Classic cardiovascular and respiratory manifestations of anemia and possibly thrombocytopenia, leukopenia, and infection.
What causes posthemorrhagic anemia & what signs and symptoms are associated with it?
- It is caused by an acute blood loss in an individual with normal iron stores (surgery or trauma).
- S/S: fatigue, parasthesias of feet and fingers, difficulty walking, cardiovascular & respiratory symptoms depending on the level of blood loss
What causes hemolytic anemia & what signs and symptoms are associated with it?
- It is caused by the episodic or continual premature accelerated destruction of RBC’s. (Destruction is greater than production of RBC’s).
- The S/S of hemolytic anemia depend on the degree of anemia and hemolysis & the success of compensatory erythropoiesis
What causes jaundice in patients who have hemolytic anemia?
- Jaundice develops when heme destruction exceeds the liver’s ability to conjugate and excrete bilirubin.
What causes sickle cell disease?
- It is caused by a genetic mutation that causes a change in a single amino acid (glutamine to valine), which results in a hemoglobin S molecule.
- When there is reduced oxygen in the blood, this causes the affected RBC’s to elongate and crescent. Sickled erythrocytes are stiff and cannot change shape as easily as normal cells when they pass through the microcirculation.
- Sickled erythrocytes tend to plug the blood vessels, causing vascular occlusion, pain, and organ infarction. Sickled cells also have a short lifespan (15 days as compared to the normal 120 days).
- They are destroyed in the spleen and the heme molecule is broken down in the liver. The increased heme breakdown may result in an increased serum bilirubin.
What are stressors that cause a sickling crisis in sickle cell disease?
- decreased Po2 (hypoxemia)
- HbS that is not bound w/ O2 causes the cells to sickle
- increased H+ in blood (decreased pH)
- increased plasma osmolality
- Promotes sickling by drawing the water out of the erythrocyte, rising the Hb S concentration in RBCs
- decreased plasma volume
- this causes the blood to become more viscous, promoting vascular obstruction of the sickled cells.
- low temperature.
How can a sickling crisis be avoided?
Crisis can be prevented by avoiding fever, infection, acidosis, dehydration, caffeine, alcohol, constricting clothing, and exposure to cigarette smoke or cold. Precautions should be taken when traveling in high altitude or receiving general anesthesia.
What causes anemia of chronic disease?
- Anemia resulting from ↓’d erythropoiesis in individuals w/ conditions of chronic systemic disease or inflammation
- ex: infections, cancer, AIDS, malaria, rheumatoid arthritis, SLE, acute & chronic hepatitis, chronic renal failure
- Inflammation from these chronic condition causes decreased erythrocyte lifespan; failure of the compensatory mechanisms of erythropoiesis; and disturbances of the iron cycle.
What are the characteristics macrocytic-normochromic anemias and which are the 2 types of normocytic-normochromic anemias?
- Characterized by unusually large stem cells (megaloblasts) in the marrow that mature into erythrocytes that are unusually large in size, thickness, and volume
Types:
- Pernicious Anemia
- folate deficiency anemia
What causes pernicious anemia & what signs and symptoms are associated with it?
- Caused by defective gastric secretion of intrinsic factor (IF) which is necessary for absorption of vitamin B12. B12 is necessary for nuclear maturation and DNA synthesis in RBC’s. Possible causes of this condition could be heredity, autoimmune, atrophic gastritis, gastrectomy or chronic alcoholism
- S/S - along with the classic signs of anemia, loss of appetite, abdominal pain, weight loss, sore tongue that is smooth and beefy red, and the skin may become lemon yellow. Neurological symptoms-loss of position and vibration sense, ataxia, spasticity.
Symptoms develop slowly over 20-30 years
What are some characteristics of folate deficiency anemia?
- Is often seen in chronically malnourished people, alcoholics.
- Associated with neural tube defects of the fetus.
- Not associated with neurological symptoms, if present then suspect a thiamine deficiency. Folate and thiamine deficiencies tend to occur together.
What are the characteristics microcytic-hypochromic anemias and which are the 2 types of normocytic-normochromic anemias?
- Anemias characterized by abnormally small erythrocytes that contain abnormally reduced amounts of hemoglobin.
Types:
- Iron deficiency anemia
- sideroblastic anemia
What causes iron deficiency anemia?
- Etiology: acute or chronic blood loss and/or inadequate dietary intake of iron. A daily loss of 2-4ml/day (1-2 mg of iron) can cause this anemia
- Pathology:
- Stage 1 - body’s iron stores are depleted but the hemoglobin content of the erythrocytes remains normal.
- Stage 2 - iron deficient erythropoiesis begins due to diminished iron transportation in the bone marrow
- Stage 3 - small, Hgb-deficient cells replace normal RBC’s. (manifestations appear in this stage)
What are the signs & symptoms of iron deficiency anemia?
- fingernail changes
- sore and dry mouth corners
- neuromuscular changes and irritability
- headache
- pale mucous membranes
- tachycardia or murmur
What causes sideroblastic anemia & what signs and symptoms are associated with it?
- Caused by altered mitochondrial metabolism resulting in ineffective iron uptake and dysfunctional hemoglobin synthesis; large numbers of sideroblast, increased iron in tissue.
- Siderblasts are erythroblasts that contain iron granules that have not been synthesized into hemoglobin; they are erythrocytes with large accumulations of iron in their mitochondria
- S/S: iron overload = hepatomegaly (liver function remains normal or slightly impaired) and splenomegaly
