Lecture Series on Anemia, Coagulation, and Transfusion Medicine

A comprehensive set of flashcards covering anemia classifications, coagulation pathways, leukogram interpretation, and transfusion medicine protocols based on veterinary lecture notes.

How is Anemia clinically defined in these notes?

A decrease in Red Blood Cell (RBC) mass.

What is the calculated formula for Hematocrit (HCT)?

$$\text{HCT} = (\text{MCV} \times \text{RBC}) \div 10$$

At what PCV level does a physiological heart murmur typically occur in severely anemic patients?

$$\text{PCV} < 25\%$$

What are the characteristics of a physiological heart murmur associated with anemia?

Left basilar, systolic, and a grade less than $2-6/6$.

What does Mean Corpuscular Volume (MCV) measure?

The average size of the Red Blood Cells (RBCs).

Which condition is classically associated with microcytic Red Blood Cells?

Iron deficiency or portosystemic shunts.

What is indicated by an increased Mean Corpuscular Hemoglobin Concentration (MCHC)?

It is always a false increase, typically due to increased free Hemoglobin in the sample, such as in hemolyzed serum.

What are the two main causes of regenerative anemia?

Hemolysis and blood loss.

How long does it take for the bone marrow to start producing new Red Blood Cells in a pre-regenerative state?

$2-5$ days.

Define Myelophthisis.

Bone marrow crowding, often due to neoplasia or infection.

What clinical finding is unique to primary or secondary bone marrow disease (non-regenerative) compared to iron deficiency?

Primary or secondary bone marrow disease typically presents as anemia alone, whereas iron deficiency usually presents with concurrent thrombocytosis.

What are the mild anemia PCV thresholds for dogs and cats?

Dogs: $30-37\%$; Cats: $20-26\%$.

Which drug is FDA conditionally approved to treat non-regenerative anemia in cats with Chronic Kidney Disease (CKD)?

Varenzin-CA1™ (molidustat)

What is the mechanism of action for Varenzin-CA1™?

It induces genetic transcription of erythropoietin (EPO), increasing both EPO and red blood cell production.

In Immune-Mediated Hemolytic Anemia (IMHA), which antibody type is typically associated with intravascular hemolysis?

IgM, which leads to the activation of complement and the formation of the Membrane Attack Complex (MAC).

Which Red Blood Cell morphology is a classic indicator of extravascular IMHA in dogs?

Spherocytes.

What are the most common causes of natural death in patients with IMHA?

Euthanasia and thromboembolism (specifically Pulmonary Thromboembolism).

Which medication is used for irreversible platelet inhibition in IMHA acute management?

Clopidogrel (Plavix®).

What is the required absolute reticulocyte count for anemia to be considered regenerative in dogs?

$$> 60,000/\mu L$$

Why are spherocytes difficult to use for diagnosis in feline IMHA?

Spherocytes are very difficult to detect in cats compared to dogs.

What is Neonatal Isoerythrolysis in cats?

A condition where Type-A kittens are born to a Type-B queen.

Define Relative Erythrocytosis.

An increase in circulating RBC mass due to hemoconcentration, typically from dehydration.

What is the goal of treating absolute erythrocytosis via therapeutic phlebotomy?

To decrease circulating RBCs and blood viscosity; the recommended volume to draw is $5-10\,mL/kg$ followed by equal fluid replacement.

When must the White Blood Cell (WBC) count be corrected manually?

When there is a significant number of nucleated Red Blood Cells (nRBCs) present, as automated analyzers often mis-count them as WBCs.

What is the difference between Primary and Secondary Hemostasis?

Primary hemostasis involves the formation of the initial platelet plug; Secondary hemostasis involves clotting factors assembling a fibrin clot to stabilize that plug.

Which platelet count range is associated with the risk of spontaneous bleeding?

$$< 20,000 - 30,000/\mu L$$

What is the cause of macrothrombocytopenia in Cavalier King Charles Spaniels?

A mutation in $\beta1$-tubulin, resulting in low counts ($50,000 - 150,000/\mu L$) of giant but fully functional platelets.

Which adhesive protein is required to bridge platelets to collagen?

Von Willebrand factor (vWF).

List the coagulation factors that require Vitamin K for activation.

Factors $II$, $VII$, $IX$, and $X$.

Which coagulation pathway does Prothrombin Time (PT) evaluate?

The Extrinsic and Common pathways.

Why does PT usually become prolonged before aPTT in Vitamin K deficiency?

Factor $VII$ has the shortest half-life of the Vitamin K-dependent factors.

Which coagulation disorder is characterized by a Factor VIII (8) deficiency?

Hemophilia A.

What are the three components of Virchow’s Triad?

Endothelial Injury, Changes in Blood Flow (stasis/turbulence), and Hypercoagulability.

What is the mechanism of action for Antifibrinolytic agents like Epsilon aminocaproic acid?

They prevent the activation of plasminogen into plasmin, thereby stopping clot breakdown.

What are the classic features of a stress leukogram?

Mature neutrophilia, monocytosis, lymphopenia, and eosinopenia.

Which endocrine disease is associated with a lack of a stress leukogram or even lymphocytosis/eosinophilia in a sick patient?

Hypoadrenocorticism (Addison’s disease).

What is the single most important diagnostic procedure for evaluating lymphadenopathy?

Fine-Needle Aspirate (FNA).

What is the most clinically important blood antigen in dogs?

DEA 1.

What makes Type B cats unique regarding blood transfusions?

They have strong naturally occurring antibodies to Type A antigens, making a Type A transfusion potentially fatal.

What is evaluated in a Major Crossmatch?

Donor Red Blood Cells + Recipient Plasma.

How much will $1\,mL/kg$ of packed Red Blood Cells (pRBC) increase a patient's PCV?

By approximately $1\%$.

Which blood product contains vWF, Factor V, Factor VIII, and Fibrinogen?

Cryoprecipitate.