SM_245b: Approach to Anemias Flashcards
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
Describe common symptoms of anemia
Anemia symptoms
- Fatigue
- Dyspnea
- Cold intolerance
- Palpitations
- Lightheadedness
- Orthostatic hypotension
Describe physical findings of anemia
Anemia physical findings
- Tachycardia
- Low BP
- Orthostatic hypotension
- Flow murmur
- Pallor
- Jaundice
Laboratory evaluation of anemia involves ___, ___, and ___
Laboratory evaluation of anemia involves CBC, reticulocyte count, and peripheral blood smear
Low Hgb, low MCV, normal WBC / platelets indicates ___
Low Hgb, low MCV, normal WBC / platelets indicates iron deficiency anemia
Low Hgb, high MCV, and low WBC indicates ____
Low Hgb, high MCV, and low WBC indicates B12 / folate / thyroid deficiencies
Low Hgb, high MCV, low / normal platelets indicates ____
Low Hgb, high MCV, low / normal platelets indicates end-stage liver disease
Low Hgb, normal MCV, high RDW indicates ____
Low Hgb, normal MCV, high RDW indicates mixed iron and B12 deficiency anemia
Low Hgb, high MCV, and low platelet count indicates ___
Low Hgb, high MCV, and low platelet count indicates possible primary bone process such as myelodysplastic syndrome or aplastic anemia
Hereditary spherocytosis involves ____
Hereditary spherocytosis involves mutations in RBC membrane proteins
Echinocytes and canthocytes are seen in ____, ____, ____, ____, and ____
Echinocytes and canthocytes are seen in Vitamin E deficiency, hypothyroidism, post-splenectomy, liver disease, abetalipoproteinemia
Echinocytes (burr cells) have ____
Echinocytes (burr cells) have more regular projections
- Usually artifact due to preparation of slide
- Can be seen in CKD, liver disease
Acanthocytes (spur cells) have ___
Acanthocytes (spur cells) have more irregular projections
- Anorexia, nutritional deficiency
Describe schistocytes
Schistocytes
- Helmet cells
- RBC schrapnel
- Intravascular destruction
- Intravascular hemolysis: complement-mediated / IgM hemolysis, enzyme deficiency (G6PD)
- Shearing and mechanical damage: artificial heart valve, mechanical circulation, DIC, TMA, HTN
Describe target cells
Target cells
- Due to excess RBC membrane relative to volume
- Macro-target cells: liver disease
- Micro-target cells: hemoglobinopathy: thalassemia, hemoglobin E and C disease
Describe Vitamin B12 deficiency
Vitamin B12 deficiency
- Pernicious anemia, gastric surgery, vegan diet, celiac disease, tapeworm
- Treat with IM Vitamin B12
Pernicious anemia is an ___ due to ___ that results in ___
Pernicious anemia is an autoimmune disease due to anti-intrinsic factor antibodies that results in Vitamin B12 deficiency
___ is a temporary way to treat anemia and the underlying cause should be treated
Transfusion is a temporary way to treat anemia and the underlying cause should be treated
In patients with hemolytic anemia, RBC transfusion can cause ____
In patients with hemolytic anemia, RBC transfusion can cause increase hemolysis
If RBC parameters are abnormal, the next step is to look at the ___
If RBC parameters are abnormal, the next step is to look at the peripheral smear
