Lecture 4 Flashcards
What species are reticulocytes NOT released in response to anemia
Horses
What are 2 ways to correct the reticulocyte percent
Calculate Absolute Reticulocyte count
Calculate corrected reticulocyte percent
How do you calculate the absolute reticulocyte count?
RBC count X uncorrected reticulocyte count as a decimal = absolute reticulocytes
How do you calculate the corrected reticulocyte percent?
(patient’s PCV/ mean norm. PCV for species) X uncorrected reticulocyte as a % = corrected reticulocyte percent
What are two causes of regenerative anemia?
Hemorrhage
Hemolysis
What are the 2 types of hemorrhage
External and internal
What are the features of external hemorrhage
RBC’s are lost
Iron is lost
Blood proteins are lost
If chronic, iron loss can be so severe RBC production stops
IF iron deficiency, non-regenerative anemia may develop
What are some causes of external hemorrhage
Trauma
Bleeding GI or UG lesions
Blood sucking parasites
some hemostatic disorders
What are the features of internal hemorrhage
RBC’s are NOT lost
Iron is CONSERVED and available to make new RBC’s
Blood proteins are NOT LOST
autotransfusion may occur from a hemoabdomen or hemothorax
What are some causes of internal hemorrhage
Trauma
Bleeding tumors of intra-abdominal or thoracic organs
some hemostatic disorders
What happens initially with acute hemorrhage?
Blood cells and blood fluid are both lost in equal amount
total blood volume is decreased
At first, PCV remains the same because relative proportion of blood cells to blood fluid is unchanged
What are the initial protective responses that occur to preserve oxygen delivery with acute hemorrhage?
Heart rate and blood pressure increase Splenic contraction (releases stored RBC's) Body tissue fluids (interstitial fluid) slowly moves from tissues to blood vessels so remaining RBC's and TP are diluted
What are 2 classic findings after hemorrhage?
anemia and panhypoproteinemia
What are the laboratory findings with acute hemorrhage
Initial findings may not reveal anything
Fluid shift starts 3 hrs post hemorrhage and continues for 2-3 days post hemorrhage
Decreased PCV and total protein will show up ~ 12-24 hours post hemorrhage
What are some factors that may influence the lab findings with acute hemorrhage?
Splenic contraction - increases PCV acutely
Autotransfusion - increases PCV slowly
Fluid therapy prior to transfusion can dilute the PCV and TP even more along with the interstitial fluid shift
How long does it take the regenerative response to anemia to appear in the blood
3-4 days
1 week in old or debilitated animals
When does the peak regenerative response occur
1 week post hemorrhage
is the regenerative response more or less dramatic in ruminants
less but more basophilic stippling
Because equids do not release reticulocytes what do we need to do evaluate the regenerative response?
Check PCV every few days
Check bone marrow
What are some things to remember when assessing regenerative anemia in horses?
Splenic contraction happens readily
Do not release reticulocytes or exhibit polychromasia
Freshly matured RBC’s are larger than older RBC’s so:
- MCV, RDW, and anisocytosis will be increased
What is the lifespan of RBC’s in circulation?
~100 days
How are old RBC’s removed
As RBC’s age, damage to the membrane occurs and the receptors on the membrane begin to trimerize which the macrophage recognizes and then engulfs the RBC
What happens when RBC’s are broken down
Hemoglobin –> Heme + globin
Heme –> iron + unconjugated bilirubin
Useful nutrients from dead RBC’s are recycled ie. iron, amino acids
liver metabolizes bilirubin which is excreted in urine and feces
What are the two classifications of hemolytic anemia
congenital and acquired
