SM_245b: Approach to Anemias Flashcards
(43 cards)
Describe erythropoiesis
Erythropoiesis
- Occurs in bone marrow
- Erythrocyte gets smaller and nucleus shrinks and is extruded during maturation
Describe a reticulocyte
Reticulocyte
- Larger than mature RBC (higher MCV), no central pallor
- Bluish collor on Wright Giemsa stain due to retention of ribosomal network
- Normally spend about 3 days in marrow and 1 day in peripheral circulation
Immature erythroid forms of RBCs are present in circulation when ____, ____, ____, or ____
Immature erythroid forms of RBCs are present in circulation when
- Normal in newborns ≤ 5 days old
- Brisk hemolysis
- Myelodysplasia
- Extramedullary hematopoiesis
Describe mature RBCs
Mature RBCs
- Anucleate
- Biconcave / discoid
- Cytoplasm: rich in iron containing Hb for O2 transport
- Normal adult Hgb is 97% HgbA: a2B2
___ stimulates RBC production
Erythropoietin stimulates RBC production
Describe RBC production and loss
RBC production and loss
- Erythropoietin stimulates production
- Circulate for 110-120 days
- Rate of production = rate of loss
- Production capacity in anemic states reflected in reticulocyte production
In anemic states, high reticulocyte count indicates ____
In anemic states, high reticulocyte count indicates adequate marrow response (e.g. bleeding)
In anemic states, low reticulocyte count indicates ___
In anemic states, low reticulocyte count indicates inadequate marrow response (e.g. aplastic anemia)
Anemia is ___
Anemia is reduction in absolute number of RBCs
Describe parameters to evaluate for anemia
Parameters to evaluate for anemia
- Hemoglobin (Hgb): concentration of Hb in whole blood
- Hematocrit (Hct): percent of a sample of whole blood occupied by RBC
- RBC count: number of RBCs in a particular volume of whole blood
- Mean cell volume: average size of RBC
- RBC distribution width
Decreased plasma volume leads to ___
Decreased plasma volume leads to artificially increased RBC concentration
- Dehydration, vomiting / diarrhea, over-diuresis, and burns
Increased plasma volume leads to ____
Increased plasma volume leads to artificially decreased RBC concentration
- Pregnancy, CHF, renal insufficiency
Compensatory mechanisms to anemia are ____, ____, and ____
Compensatory mechanisms to anemia are increased cardiac output, increased EPO, and increased 2,3 DPG
- Fick equation: O2 delivery = blood flow x Hgb x (Arterial SaO2 - venous SaO2)
RBC size is determined using ___
RBC size is determined using MCV
Describe causes of normocytic anenmia
Normocytic anemia
- Anemia of chronic disease
- Blood loss
- Hemolytic anemia
- > 1 etiology
Describe causes of macrocytic anemia
Macrocytic anemia
- Folate or B12 deficiency
- Liver disease
- Hemolysis
- Myelodysplasia
- Hypothyroidism
- Hemolysis
- > 1 etiology
Describe causes of microcytic anemia with low RBC count
Microcytic anemia with low RBC count
- Iron deficiency
- Sideroblastic
- Hemolytic anemia
- Lead poisoning
Describe causes of microcytic anemia with high RBC count
Microcytic anemia with high RBC count
- Thalassemia (alpha or beta, trait or disease)
Mentzer Index = ____ + ____
Mentzer Index = MCV + RBC count
Mentzer Index < 13 indicates ___
Mentzer Index < 13 indicates thalassemia is more likely than iron deficiency
Describe examples of how anemia can result from ≥ 1 process
Anemia can result from ≥ 1 process
- Iron and B12 deficiencies -> microcytosis and macrocytosis -> average MCV is normal
- Higher RDW
- Iron, B12, and folate levels should be low
Under the kinetic approach, anemia can result from ____, ____, or ____
Under the kinetic approach, anemia can result from decreased RBC production, blood loss, and RBC destruction
Describe variation in symptoms of anemia
Anemia symptoms
- Acute: signs and symptoms more likely - orthostatic dizziness, headache, tachycardia
- Insidious onset / chronic anemia: hemodynamic symptoms such as lightheadedness less common due to expansion of plasma volume, often able to tolerate lower Hb levels due to body adaptations
