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157 Cards in this Set
- Front
- Back
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3 potential causes of false decreases in erythrocyte counts
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- Fragile RBCs
- Agglutination - Operator error (not filling tube to proper volume) |
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Two potential causes of false increases in erythrocyte counts
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- Debris
- Platelet clumping |
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What should hemoglobin concentration be in regards to PCV?
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1/3 PCV
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Three causes of a false increase in [Hgb]
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- Lipemia
- Heinz bodies - Oxyglobin |
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Numerical relationship of HCT and PCV
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Should be within 10% of each other
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Two causes of a false HCT decrease
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- Leaking hematocrit tube
- Sample dilution due to improper test tube filling |
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What is MCV?
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Mean Cell Volume
- Volume of the average RBC to estimate size |
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Term used to refer to an MCV that's within the reference interval
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Normocytic
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Term used to refer to an MCV that's above the reference interval
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Macrocytic
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Term used to refer to an MCV that's below the reference interval
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Microcytic
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What is MCHC?
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Mean Cell Hemoglobin Concentration
- Hb concentration of average RBC |
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Why can't an RBC be hyperchromic in terms of Hgb?
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Each cell can only hold 4 hemoglobins, no more.
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What is RDW?
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Red Cell Distribution Width
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What does an abnormal RDW signify?
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Anisocytosis
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What stain stains reticulocytes purple?
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Rowanowsky stain
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What stain stains reticulocytes blue?
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New Methylene Blue
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What are reticulocytes released in response to?
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Anemia
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What level of reticulocytes in dogs suggests a regenerative anemia?
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> 80,000 reticulocytes / ul
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What level of reticulocytes in cats suggests a regenerative anemia?
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> 60,000 reticulocytes / ul
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What should NOT be used to determine if an anemia is regenerative?
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Presence of nRBCs
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Which domestic species does not have reticulocytes that are found in peripheral circulation?
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Horses
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Two species that have reticulocytes in the peripheral blood only during anemia
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- Ruminants
- Camelids |
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Which species' young has a prominent reticulocytosis?
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Pigs, in suckling piglets
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Four causes of rouleaux
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- Inflammation
- Increased CNH - Fibrinogen - Increased [Globulin] |
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Which species has rouleaux normally? (3)
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- Cats (mild)
- Pigs (mild) - Horses (can be marked) |
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What does polychromasia indicate?
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Presence of reticulocytes
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What is hypochromasia caused by?
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Decreased MCHC
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What blood parameter does anisocytosis correlate with?
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RDW
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4 things that might cause nucleated RBCs in the absence of anemia
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- Marrow damage (trauma, heat stroke, necrosis, ischemia)
- Splenic dysfunction - Absence of a spleen - Lead toxicity |
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What level of poikilocytosis is clinically significant?
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> 1%
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Discocyte (define)
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Biconcave discoid erythrocyte
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4 disease states that can cause echinocytes
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- Snake bite
- Dehydration - Renal disease - Lymphoma |
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3 diseases that are associated with acanthocytes
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- Liver disease
- Vascular tumors - Lipid disorders |
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What level of acanthocytosis is clinically significant?
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Any, even in low proportions
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What causes eccentrocytes?
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Oxidative damage to the RBC
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What causes schistocytes?
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Mechanical trauma to the RBC
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4 disease states that are associated with schistocytes
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- Fibrin deposition
- Tumor of blood vessels - Heart failure - Glomerulonephritis |
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What causes spherocytes?
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Macrophages removing portions of RBC membrane
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What disease state are spherocytes most commonly associated with?
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IMHA
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Leptocytes (define)
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Catch-all term for hypochromic appearing red cells that have an increased membrane:cytoplasm ratio
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What are codocytes associated with? (2)
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- Regenerative anemia
- Liver disease |
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In what species are stomatocytes clinically significant, and what do they indicate? (2)
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Dogs
- Hereditary disorder - Chronic anemia |
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Knizocytes (define)
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Triconcave-like RBC with central bar of Hgb
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Keratocyte (define)
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'Helmet cell'
- Thought to result from rupture of a vacuole that formed near the cell surface |
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3 general causes of keratocytes
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- Physical injury
- Chemical injury - Oxidative injury |
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What are the blue dots in basophilic stippling?
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Aggregates of RNA
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How does basophillic stippling appear on Romanowsky stain?
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Small, faint blue dots
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What is basophillic stippling seen in?
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Regenerative anemias
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What clinical condition is basophillic stippling seen most commonly in?
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Lead toxicity
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When should lead toxicity be highly suspected with basophillic stippling?
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When there's a basophillic stippling without a concurrent anemia and reticulocytosis
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What are Heinz bodies and what are they a result of?
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Denatured hemoglobin
- Occurs with oxidative damage |
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Which species is particularly prone to Heinz body formation?
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Cats
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How do Heinz bodies appear on a Romanowsky stain?
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Pale circles inside the cell or blebs on the periphery
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How do Heinz bodies appear on a New Methylene Blue stain?
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Bright blue
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How long do RBCs live for?
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100 days
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What are the two basic routes for RBC removal and what is the primary one?
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- Extravascular hemolysis ***
- Intravascular hemolysis |
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What destroys cells in extravascular hemolysis?
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Macrophages
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3 constituents of RBCs and how they're used
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- Globulin (broken down in AAs)
- Iron (recycled) - Protophyrin ring of hemoglobin (broken down into biliverdin, then bilirubin |
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How does intravascular hemolysis affect gross serum appearance?
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Turns it red (hemolysis) due to increased free hemoglobin
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What protein binds hemoglobin in the blood?
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Haptoglobin
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What two symptoms can intravascular hemolysis lead to?
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- Hemoglobinuria
- Pigmentary nephropathy |
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What ultimately causes a hemolytic anemia?
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RBC destruction outpacing marrow's ability to produce new ones
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3 things that Hgb synthesis depends on
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- Adequate iron supply and delivery
- Synthesis of protophyrins - Synthesis of globins |
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Which form of iron does O2 bind to?
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Ferrous (unoxidized)
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Two main forms of hemoglobin
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- Oxyhemoglobin (O2 saturated)
- Deoxyhemoglobin (O2 desaturated) |
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The phenomena of when one O2 binds to hemoglobin, all progressive O2 binds easier (term)
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Cooperativity / heme-heme interaction
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4 things that shift the oxygen-dissociation curve right
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- Increase in temperature
- Increase in 2,3-DPG - Increase in CO2 - Decrease in pH |
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What form of hemoglobin occurs with exposure to CO?
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Carboxyhemoglobin
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What form of hemoglobin occurs with toxins?
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Methemoglobin
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What form of hemoglobin occurs with cyanide exposure?
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Cyanmethemoglobin
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What form of hemoglobin occurs with a hereditary deficiency in the synthesis of globin?
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Thalassemia
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What form of hemoglobin occurs with an alteration in the genetically determined molecular structure of Hgb?
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Hemoglobinopathy
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What are iron levels in the blood primarily controlled by?
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Uptake in intestines
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How much iron is stored in hemoglobin?
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About 65%
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30% of the body's iron is stored in what three organs?
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- Spleen
- Liver - Bone marrow |
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What are the two forms of iron?
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- Ferritin
- Hemosiderin |
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What form of iron is found primarily in cells?
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Ferritin
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What form of iron can be used to estimate body stores?
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Ferritin
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What can increase the production of ferritin?
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Inflammation
- Ferritin is an acute phase protein |
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What stain stains for hemosiderin?
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Prussian Blue
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What transports iron in the blood?
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Transferrin
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How saturated is transferrin generally?
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30%
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What is an indirect measure of transferrin?
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TIBC
- Transferrin Iron Binding Capacity |
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Relationship of TIBC to serum iron concentration
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TIBC = 3x serum [iron]
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What is low serum ferritin seen in?
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Iron deficient states
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What is high serum ferritin seen in? (5)
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- Iron overload states
- Liver disease - Infection - Inflammation - Malignancy |
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In an iron deficient state that's not complicated by concurrent inflammatory disease, what is the degree of:
Serum iron concentration TIBC Percent transferrin saturation |
- Low serum iron concentration
- Normal to high TIBC - Low percent transferrin saturation |
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In an iron overload state, what is the degree of:
Serum iron concentration TIBC Percent transferrin saturation |
- High serum iron concentration
- Low TIBC - High percent transferrin saturation |
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In Hemolytic anemia, what is the degree of:
Serum iron concentration Percent transferring saturation |
- High serum iron concentration
- High percent transferrin saturation Similar to an iron overload state, due to lots of free Hgb? |
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In an iron deficient state with inflammatory disease, what is the degree of:
Serum iron concentration TIBC |
- Low serum iron concentration
- Low TIBC |
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What do RBCs primarily use for energy?
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Glc
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How do RBCs generate their energy?
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Glycolysis
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4 biochemical pathways that are present in mature erythrocytes
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- Embden-Myerhof pathway
- Hexose-monophosphate pathway - Methemoglobin reductase pathway - Luebering-Rapoport pathway |
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What does the Embden-Myerhof pathway in RBCs do?
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Generates ATP
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What does the Hexose-monophosphate pathway in RBCs do?
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Maintains glutathione in reduced state to protect RBCs from oxidants that denature Hgb
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What does the methemoglobin reductase pathway in RBCs do?
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Maintains iron in reduced state
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What does the Luebering-Rapoport pathway in RBCs do?
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Generates 2,3-DPG which aids in ability of Hgb to bind or release O2
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Polycythemia (define)
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Increased total erythrocyte mass in blood
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Increased erythrocyte mass secondary to nonhematopoietic systemic disorders
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Erythrocytosis
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Increased concentration of blood components because of a decreased plasma volume
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Hemoconcentration
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What is primary absolute polycythemia?
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A myeloproliferative disorder where there is an increase in division of erythroid series
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What is secondary absolute polycythemia caused by?
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Increased erythropoietin secretion
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Two types of secondary absolute polycythemias
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- Appropriate
- Inappropriate |
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What can secondary absolute polycythemias be secondary to?
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Chronic hypoxia
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What occurs in a relative polycythemia?
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Total RBC mass remains normal but red cell parameters change
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What occurs in a relative polycythemia caused by hemoconcentration or dehydration?
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- Increase in RBC parameters
- Increase in plasma protein concentration |
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What occurs in a relative polycythemia caused by redistribution of red cells?
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Epinephrine release and subsequent splenic contraction results in release of splenic RBCs into circulation
- No increase in plasma protein concentration |
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3 blood values that decrease in anemia
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- HCT
- RBC count - [Hgb] |
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Three ways to classify anemias
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- According to cell size and [Hgb]
- According to bone marrow response - According to pathophysiologic mechanism |
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3 common patterns of an anemia due to cell size and [Hgb]
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- Macrocytic, hypochromic
- Microcytic, hypochromic - Normocytic, normochromic |
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What is the macrocytic, hypochromic anemia pattern most often seen in?
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Regenerative anemias
- So anemias caused by hemolysis or hemorrhage |
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What is a microcytic, hypochromic anemia pattern associated with?
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Disorders of Hgb production
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Morphology of RBCs in a microcytic, hypochromic anemia pattern
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Small due to poor Hgb production; cells divide an abnormal amount of times trying to reach a specific IC [Hgb]
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What is a normocytic, normochromic anemia pattern associated with?
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Poor or inadequate bone marrow response
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What is the most common cause of a normocytic, normochromic anemia pattern?
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Chronic disease
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What are three possible themes one should think of in a regenerative anemia?
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- Reticulocytosis
- Blood loss - RBC destruction (hemolysis) |
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How long does it take after an anemic insult to see reticulocytes in the peripheral blood?
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2 - 3 days
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How long does it take to see a strong response to an anemic crisis?
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About a week
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Which species has the greatest ability to respond to an anemic crisis?
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Dogs
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In the cat, which type of reticulocyte indicates a recent insult?
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Aggregate reticulocyte
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Which species does not have reticulocytes, and how do you determine if an anemia is regenerative in it? (3)
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Horse
- Monitor serial CBCs/PCVs, look for presence of anisocytosis, and increased MCV. |
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3 things a regenerative anemia is characterized by
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- Increased polychromasia
- Increased reticulocytes - Increased RDW |
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What anemia pattern is a regenerative anemia?
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Macrocytic, hypochromic
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Two most common causes of a regenerative anemia
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- Blood loss/hemorrhage
- Accelerated hemolysis |
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Two types of blood loss anemia
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- External
- Internal |
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What is lost in an external hemorrhage?
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All components of blood
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What is lost in an internal hemorrhage?
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Only the RBCs themselves
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Why is an external hemorrhage often more severe than an internal one?
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All components of blood are lost in external hemorrhage, so can't recycle constituents to help respond faster as you can in internal
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What are two concurrent conditions with external hemorrhage?
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- Hypoproteinemia
- Hypoalbuminemia |
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Why might an initial drop in PCV not be appreciated in acute blood loss? (2)
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- Both blood cells and plasma are lost
- Spleen contracts to add cells to circulation |
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Two clinical signs with acute blood loss
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- Hypovolemia
- Hypoxia |
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What characteristic seen in acute blood loss is usually not seen in chronic blood loss?
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Hypovolemia
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Progression of an iron deficiency anemia
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Macrocytic, hypochromic --> normocytic, normochromic --> microcytic, hypochromic
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Two classes of animals that develop iron deficiency easily
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- Nursing animals (milk is low in animal)
- Growing animals (reservoirs of iron are low) |
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7 expected laboratory findings of iron deficient anemia
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- Shift from normocytic, normochromic to microcytic, microchromic (usually don't see macrocytic, hypochromic state by time animal gets to you)
- Regenerative to non-regenerative shift - Low serum iron - High end of normal to high TBIC - Low ferritin - Decreased hemosiderin in bone marrow - Erythroid hyperplasia in bone marrow |
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What cell type often characterizes an IMHA?
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Spherocytes
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How are RBCs destroyed in an extravascular hemolysis?
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Sequestered in spleen or liver and phagocytosed
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What anemia pattern is extravascular hemolysis typically?
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Macrocytic, hypochromic
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Read over the smorgasborg of mechanisms that can cause an extravascular hemolysis on pg. 95
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Read over the smorgasborg of mechanisms that can cause an extravascular hemolysis on pg. 95
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When does hemolysis in the serum become apparent?
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Around 50 - 100 mg/dl of free Hgb
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What value is falsely increased in intravascular hemolysis?
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MCHC
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What pattern of anemia does intravascular hemolysis fit?
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Macrocytic, hypochromic
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Many of the mechanisms that cause extravascular hemolysis also cause intravascular hemolysis
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Review on page 98
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2 reasons why a non-regenerative anemia occurs
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- Reduce erythropoiesis
- Ineffective erythropoiesis |
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3 characterizations of a non-regenerative anemia
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- Little to no polychromasia
- Low retic counts - No anisocytosis |
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What anemia pattern does a non-regenerative anemia fit?
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Normocytic, normochromic
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6 basic mechanisms that can cause reduce erythropoiesis
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- Anemia of chronic disorders
- Lack of erythropoietin - Immune-mediated - Bone marrow damage - Myelopthisis - Infection |
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5 effects that anemia of chronic disease has on iron in the body
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- Iron becomes sequestered and unavailable for erythropoiesis
- Normal to decreased TIBC (due to sequestered iron) - Decreased serum iron - Increased ferritin - Increased marrow hemosiderin |
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2 causes of decreased erythropoietin production
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- Chronic renal disease
- Endocrinopathies |
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How does chronic renal failure affect erythropoietin production?
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As renal parenchyma is destroyed, erythropoietin production decreases
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How do endocrinopathies affect erythropoietin production?
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Erythropoietin is enhanced by several hormones, so hormone deficiencies will lead to erythropoietin deficiencies
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3 basic mechanisms that lead to ineffective erythropoiesis
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- Disorders of hemoglobin synthesis
- Disorders of nucleic acid synthesis - Abnormal maturation or production |
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Anemia pattern associated with an ineffective erythropoiesis
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- Microcytic hypochromic
- Macrocytic normochromic |
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3 causes of ineffective erythropoiesis caused by a microcytic, hypochromic anemia
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- Iron deficiency
- Copper deficiency - Pyridoxine deficiency |
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How should an animal with a portosystemic shunt appear? (2)
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- Microcytic with a mild anemia
- Microcytic with a PCV within RI |
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2 causes of ineffective erythropoiesis caused by a macrocytic, normochromic anemia
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- Megaloblastic anemia
- Vitamin B12 and folic acid deficiencies (rare) |
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3 conditions that megaloblastic anemias are associated with
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- Feline Leukemia Virus
- Myelodysplasia - Myeloproliferative disease |
