L24- Anemias (#6) Flashcards
What is anemia defined as?
Abnoramlly low red blood cell mass
How is anemia determined?
Measuring the packed cell volume (PCV) or hematocrit (HCT) in a whole blood sample
Describe plasma vs serum.
Plasma: watery, straw-colored fluid protion that results after removal of blood cells
Serum: clear, thin, sticky fluid that remains after coagulation of the plasma sample- contains no blood cells or coagulation factors
Anemia is a ________________, but not a disease itself1
Sign of a disease
The most useful approach in the classification of anemia is to determine whether or not evidence of a ___________- response is present in the blood.
Bone marrow
There are two main groups of anemia- what are they?
Regenerative anemias
Non-regenerative anemias
What is regenerative anemias?
Where the body is able to respond appropriately to the decreased red cell mass by increasing RBC production
What is non-regenerative anemia?
Where the body is unable to respond adequately to the increased need for RBCs
what is erythropoiesis?
Production of RBCs in the bone marrow
RBCS are _________- by resident macrophages but _________________ by erythropoiesis (in bone marrow)
Continually destroyed
Continually replaced
When RBCs are in demand, the pluripotent stem cell will receive certain signals that trigger differentiation into a ___________________cell
Erythroid colony-forming unit (CFU)
With each division, the blast cell undergoing multiple rounds of cell divisions gets _______
Smaller
Although the blast cell gets smaller with each dvision, it is however _____________________
Increasing its Hb content
The final stage before becoming an erythrocyte is termed the _____________
Reticulocyte
What are three features of reticulocytes?
- Contain 80% of total Hb present in a mature RBC
- Do not contain nucelus
- 20% larger than mature RBCs due to presence of ribosomes, mitochondria, RNA
When are reticulocytes released when a) in normal condition, and b) in cases of anemia?
Normal condition: takes about 2-4 days for reticulocytes to mature into RBCs
Anemia: Reticulocytes can be released early from the bone marrow
Reticulocytopenia indicates what?
A low number of circulating reticulocytes
What protein hormone stimulates the process of red cell blood produciton?*
Erythropoietin (EPO)
Where is EPO produced? In response to what?
EPO is a growth factor produced in the kidney in response to renal hypoxia
The EPO receptor is located where?
In the bone marrow
EPO levels are ________ in the case of anemia
Increased
Clinical note: at least _____________ is needed to produce EPO
one healthy kidney
EPO exerts its effects in the following 5 ways:
- Increase number of erythroid CFU cells thru inhib of CFU-E cell programmed death (apoptosis)
- Increased rate of Hb synthesis
- Increased iron absorption
- Increased rate of erythroid differentiation
- Stimulated production and premature release of reticulocytes from bone marrow into circulation (reticulocytosis)
What are the two nutrients especially needed to adequate cell division (DNA Synthesis)?
- Folic acid
2. Vit B12
What are 4 nutrients especially needed for adequate Hb synthesis (protein synthesis)?
- Dietary protein (AA)
- Iron
- Copper, since one of the iron transporteres req copper
- Vit B6, needed for syn of heme group
All anemias will result in increased levels of what 2 things?
Erythropoietin and 2,3 BPG
What does the corrected reticulocyte percentrage (CR or CRP) indicate when it is increased?*
Indicates that the body is ABLE to prod RBCs in response to an elevated EPO level. Thus, anemia is REGENERATIVE
Regenerative anemia is likely to be caused by what kind of examples?
RBC lysis or loss
What does the corrected reticulocyte percentrage (CR or CRP) indicate when it is decreased or remains within reference range?*
Indicates that the body is unable to produce erythrocytes in spite of having an elevated EPO level. Anemia is NONREGENERATIVE
What is non-regenerative anemia likely to be caused by?
Insufficient erythrocyte production
If HCT levels are within range, what does that say?
No anemia
If HCT levels are out of range, what does that indicate?
Anemia is present
In the Complete Blood Count, what is RBC, HGB, and HCT?
RBC: red blood cell count
HGB: Hb concentration
HCT: Hematocrit aka packed red cell volume
How is HCT calculated?
Using the MCV equation and RBC count
How is PCR determined by?
Centrifuging blood and determining the percentage- % of lenght of entire RBCs in column is the PCV
What is corpuscular indices used for?
Determining the morphological classification of the anemia
what is the Mean corpuscular volume (MCV)? Equation?
Average volume of erthryocytes
MCV = (HCT/RBC) *10 [fL units]
By comparing MCV values with average, we can definite three things and their ranges- what are thye?
MICROCYTIC when MCV 77 (larger than avg)
What is Mean corpuscular hemoglbin (MCH)? Equation?
MCH is the quantity of Hb in the average circulating erythrocyte
MCH= (HGB/RBC) * 10 [pg units]
What is Mean corpuscular Hb concentration (MCHC)? equations?
Concentration of Hb in the avg circulating erythrocyte
MCHC= HGB/HCT *100 [%] MCHC = MCH/MCV *100 [%]
By comparing MCHC values with average, we can definite three things and their ranges- what are they?
NORMOCHROMIC when MCHC is within the 31-37% range
HYPOCHROMIC when MCHC
What are examples of non-regenerative anemia (cases)
- Anemia of chronic disease
- Renal failure
- Vit deficiency
- Iron deficiency (can also be regenerative)
What are 2 categories of examples of regenerative anemia (cases)?
- Hemorrhage/ Loss
2. Hemolysis/ Lysis
What are examples of hemorrhage cases of regenerative anemia?
Trauma, GI ulceration, hemostasis defect, neoplasia, parasitism
What are examples of hemolysis cases of regenerative anemia?
PFK deficiency, PK deficiency, toxicity, immune mediated
Study Q: What is anemia?
Low HCT or PCV level in a whole blood sample
Study Q: What lab value distinguishes anemia due to premature loss of red cells from those resulting form insufficient RBC production?
Corrected reticulocyte percentage (CR)
Study Q: What is the meaning of a normal corrected reticulocyte count with low HGB, HCT and RBC?
Anemia w/ impaired red cell production
Study Q: What would happen to the reticulocyte count after administration of iron supplements to a puppy with iron deficiency anemia?
It would increase to well above normal
What breeds has Vit B12 malabsorption been reported in?
Border collie, Beagle, Giant Schnauzer dogs, and also in cats
What causes Vit B12 malabsorption?
Hereditary absence of Intrinsic Factor receptor
Study Q: What Vit B12 containing protein will have decreased activity?
Methylmalonyl-CoA mutase, and 1-methyl malonyl0CoA will be elevated in urine
Study Q; What Tx would be recommened?
Parenteral (not oral) injections of Vit B12
