Anemia and Red Blood Cell Assessment

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Questions and Answers

What characterizes appropriate rubricytosis?

Presence of nRBCs without reticulocytosis

Marked polychromasia without marked regeneration

Disproportionate nRBCs relative to regenerative response

Intensely regenerative anemias with high reticulocytes (correct)

What does microcytic anemia indicate about the RBCs?

They are of normal size and color

They are larger and more colored than normal

They are overproduced in response to blood loss

They are smaller and paler than normal (correct)

In the classification of anemia, what does normocytic normochromic anemia suggest?

High levels of reticulocytes and polychromasia

A regenerative response without any average change

An absence of regeneration in response to anemia (correct)

The presence of small and pale RBCs

What is true about macrocytic anemia in dogs?

About 30% of dogs with regenerative anemia present this pattern Signup and view all the answers

What role does RDW play in the assessment of anemia classification?

It aids in deciding if anemia is regenerative or non-regenerative Signup and view all the answers

What is the primary function of red blood cells (RBCs)?

Carrying oxygen to tissues Signup and view all the answers

What term describes a decrease in red blood cell mass?

Anemia Signup and view all the answers

Which of the following is a classification type of anemia based on bone marrow response?

Regenerative anemia Signup and view all the answers

Which of the following clinical signs is most directly related to anemia?

Lethargy Signup and view all the answers

What does the MCV measure in red blood cells?

Mean corpuscular volume Signup and view all the answers

What type of anemia is characterized by the loss of blood?

Blood loss anemia Signup and view all the answers

What is the role of reticulocytes in diagnosing anemia?

They represent immature RBCs and indicate bone marrow activity Signup and view all the answers

What is NOT a clinical consequence of anemia?

Hypertension Signup and view all the answers

What condition is indicated by a low hemoglobin level in this case?

Non-regenerative anemia Signup and view all the answers

What is the likely cause of the elevated reticulocyte count?

Increased red blood cell destruction Signup and view all the answers

Which laboratory finding suggests hyperbilirubinemia?

Elevated bilirubin levels in plasma Signup and view all the answers

What symptom is most likely associated with the patient's icteric appearance?

Elevated bilirubin levels Signup and view all the answers

What does a decreased MCHC indicate in the patient’s results?

Iron deficiency anemia Signup and view all the answers

Which clinical sign is NOT typically associated with anemia?

Severe weight gain Signup and view all the answers

What does the presence of petechia or ecchymoses in a patient with anemia suggest?

Possible coagulopathy or blood loss Signup and view all the answers

Which of the following tests is NOT part of the minimum database for evaluating anemia?

Coagulation panel Signup and view all the answers

Which RBC index assesses the average concentration of hemoglobin in a given volume of red cells?

MCHC Signup and view all the answers

What is the purpose of performing a Coombs' test in the evaluation of anemia?

To detect immune-mediated hemolysis Signup and view all the answers

Which of the following is a sign of possible extramedullary hematopoiesis in a case of anemia?

Organomegaly Signup and view all the answers

What is the main goal of the laboratory evaluation for anemia?

To determine severity and underlying cause Signup and view all the answers

Which additional test is best suited for identifying infectious agents in cases of anemia?

PCR for infectious agents Signup and view all the answers

What type of anemia is characterized by macrocytic, hypochromic red blood cells?

Regenerative anemia Signup and view all the answers

Which red blood cell index is primarily used to assess the type of anemia present?

Reticulocyte count Signup and view all the answers

What is a common cause of microcytic, hypochromic anemia?

Nutritional deficiencies such as iron deficiency Signup and view all the answers

Which mechanism of anemia is associated with increased reticulocyte counts?

External blood loss Signup and view all the answers

Which statement about normocytic, normochromic anemia is correct?

It typically implies decreased RBC production. Signup and view all the answers

What underlying condition might cause non-regenerative anemia?

Nutritional deficiencies Signup and view all the answers

Which of the following anemias can be classified as a result of hemolysis?

Normocytic, normochromic anemia Signup and view all the answers

Which dog breeds are known to have microcytic, normochromic conditions without anemia?

Shiba Inu, Chow Chow, Akita, and Shar Pei Signup and view all the answers

What occurs when unconjugated bilirubin builds up in the blood?

It results in high total bilirubin values. Signup and view all the answers

Which characteristic primarily distinguishes intravascular hemolysis from extravascular hemolysis?

RBCs are destroyed in the vasculature. Signup and view all the answers

Which of the following is most commonly associated with regenerative anemias?

Increased RBC production in the bone marrow. Signup and view all the answers

What is bilirubinuria indicative of?

Increased hemolysis. Signup and view all the answers

What condition is typically associated with fragmentation anemia?

Conditions causing increased RBC fragility. Signup and view all the answers

What is a common sign of hemoglobinemia?

Presence of free hemoglobin in circulation. Signup and view all the answers

Which parameter is NOT directly associated with hemolysis?

Bone marrow atrophy. Signup and view all the answers

What is the primary role of macrophages in hemolytic anemia?

To phagocytose RBCs. Signup and view all the answers

Study Notes

Anemia Classification and Approach

Anemia is defined as a decrease in red blood cell (RBC) mass, characterized by a decreased RBC count, hemoglobin, hematocrit (HCT), and packed cell volume (PCV).

Self-Study Questions

Red blood cells (RBCs) are produced in the bone marrow.
Erythropoietin stimulates RBC production.
The primary function of RBCs is to carry oxygen to tissues.
A decrease in RBC mass is called anemia.
An increase in RBC mass is not anemia.
Commonly reported RBC parameters on a complete blood count (CBC) include mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), and red cell distribution width (RDW).
MCV, MCHC, and RDW are used for classification of anemias; they indicate the size and hemoglobin content of red blood cells; abnormal values often help indicate the underlying cause of anemia.
Reticulocytes are immature red blood cells.
Reticulocyte counts and morphology are used to determine if the bone marrow is responding to the anemia or not.
Mammals, birds, reptiles, and amphibians have different types of red blood cells.

Learning Objectives

Recognize and classify anemia based on bone marrow response and the underlying mechanism
Discuss the pathophysiology and pathogenesis of blood loss and hemolytic anemias and how to differentiate them clinically and through a CBC
Identify non-regenerative anemia using available data, construct species-appropriate differential diagnoses, and discuss pathogenesis and clinical findings

Lecture Overview

Anemia is a clinical syndrome characterized by a decrease in RBC mass and reduced oxygen-carrying capacity of the blood.
Anemia is classified based on red blood cell indices (MCV, MCHC), bone marrow response (reticulocytes), and the underlying cause (blood loss, destruction/hemolysis, decreased production).
Regenerative anemia follows blood loss or hemolysis (RBC destruction) and shows a reactive bone marrow response.
Non-regenerative anemia follows decreased RBC production and shows an inadequate bone marrow response.

Anemia: Definition

Anemia is characterized by a decrease in the concentration of circulating red blood cells (RBCs), hemoglobin(Hgb), and packed cell volume (PCV) or hematocrit (HCT).

Erythrogram (CBC Data Example)

A sample case study presents data with RBC, HGB, HCT, MCV, MCH, MCHC, RDW, Platelets, and WBC counts along with a differential. The result reflects a healthy or deficient animal.
Additional microscopic findings like the presence or absence of polychromasia, a condition indicating increased immature red blood cell numbers.
The information provided in the case study can help in the diagnosis and treatment of anemia in the respective animal.

Anemia: Clinical Consequences

Reduction in oxygen-carrying capacity of the blood—hypoxemia—leads to potential oxygen-deprived tissue damage.
Clinical signs of anemia include lethargy, exercise intolerance, and other signs depending on severity, rate of onset, and underlying cause.

Anemia—Clinical Diagnostic Approach

A physical exam assesses physiological signs like pale mucous membranes, weakness, tachycardia (fast heart rate), bounding pulse, and/or heart murmurs, respiratory effort, blood loss signs, organomegaly, lymphadenopathy, and parasites to aid in cause diagnosis.
Blood loss with or without coagulopathy is determined.
Signs of internal or external trauma may be present to determine underlying cause diagnosis.

Anemia—Laboratory Diagnostic Approach

A minimum database (MDB) includes a complete blood count (CBC), chemistry profile, urinalysis.
CBC parameters are measured to document and assess anemia severity, and evaluate for bone marrow response.
Chemistry profile (bloodwork) assists in identifying underlying diseases and provides clues to the potential cause.
Urinalysis helps in the complete evaluation of the renal system.

Anemia—Diagnostic Approach

Additional tests for anemia diagnosis can include fecal exams for parasites, Coombs' testing for immune-mediated hemolysis, coagulation tests (bleeding disorders), imaging, PCRs for infectious agents (hemoparasites), bone marrow examination (severe non-regenerative anemia, pancytopenia), and biopsy/aspirates (neoplasia, infection, inflammation).

Anemia Classification

Anemia is classified based on bone marrow response (regenerative vs. non-regenerative), RBC indices (MCV, MCHC, RDW), and the underlying mechanism (blood loss, hemolysis, or decreased RBC production).

Anemia Classification: Big Picture

Regenerative anemia is characterized by an elevated reticulocyte count and polychromasia (immature RBCs), indicating a responsive bone marrow.
Non-regenerative anemia has a decreased or absent reticulocyte count and shows inadequate bone marrow response.
Species variation in reticulocyte response needs to be accounted for.

Review

Review the Foundation 2a RBC lecture 1 & 2 for more details.

Classification by Bone Marrow Response

Use reticulocyte count and polychromasia to assess bone marrow response in classifying anemia; distinguish between regenerative and non-regenerative forms of anemias.

Reticulocytes

High counts indicate regenerative bone marrow responses to anemia.
Mild cases may show no significant increase.
Species variation in normal reticulocyte values needs to be considered.

What About nRBCs?

Nucleated red blood cells (nRBCs) are usually metarubricytes, can indicate severe or abnormally high regenerative response.
Correct the WBC count if the value goes above a critical threshold.
nRBCs can be misleading in automated cell counts as they have nuclei like white blood cells (WBCs).

Anemia Classification Using RBC Indices

Primarily based on MCV and MCHC.
Microcytic/hypochromic: small, pale RBCs, often associated with iron deficiency.
Normocytic/normochromic: normal size and hemoglobin content of RBCs, common in various conditions including inflammation and/or CKD.
Macrocytic/normochromic: large RBCs with normal hemoglobin content, associated with certain regeneration and specific regenerative pathologies.

Classification of Anemia: RBC Indices, Summary

The classifications using RBC indices, combined with bone marrow responses and other tests, provide more context to help determine the best treatment plan.

Classification by General Mechanism

Includes blood loss, RBC destruction (hemolysis), and decreased RBC production.

Classification of Anemia by Mechanism

Hemorrhage, Blood loss: internal/external, regenerative anemia.
Hemolysis: intra/extravascular, regenerative anemia.
Decreased production: non-regenerative anemia, typically normocytic, normochromic.

RBC Destruction in Health

Physiologic removal of a percentage of old or damaged RBCs (extravascular hemolysis) is critical.
Pathologic causes of hemolysis and premature destruction of RBCs can result in anemias.

RBC Destruction in Health (Detailed)

Phagocytized RBCs are broken down into components.
Hemoglobin is converted to unconjugated bilirubin and transported to the liver, where it's conjugated and then excreted into bile.
Pathologic premature destruction of RBCs can lead to various types and causes of hemolysis.

Premature RBC Destruction Leading to Hemolytic Anemia

Extravascular hemolysis: unconjugated bilirubin is produced from the macrophages than the liver can handle—causing a build-up of unconjugated bilirubin in the blood, leading to high total bilirubin values.
Intravascular hemolysis: the free hemoglobin is released into the circulation, taken up by macrophages, and converted to bilirubin; most of the hemoglobin is filtered through the kidneys.

Regenerative Anemias

Table: Bone marrow response, plasma/serum protein, hemoglobinemia, hemoglobinuria, RBC morphology, hyperbilirubinemia, bilirubinuria, and Coombs' test in blood loss and hemolytic scenarios.

Regenerative Anemias - Hemolysis

Hemolysis, destruction of RBCs, is a category for classifying anemia, involving extravascular (phagocytosed by macrophages) and intravascular (RBC lysis) hemolysis.

Extra-vs-Intravascular Hemolysis

A comparison table analyzing the onset, hemoglobinemia, hemoglobinuria, morphology changes, hyperbilirubinemia, bilirubinuria, MCHC, and reticulocytosis of extravascular vs intravascular hemolysis.

Hemolytic Anemias - Overview

Hemolytic anemias can arise from immune-mediated diseases, oxidative damage, infectious causes, and fragmentation of RBCs.

Cases

Case studies (like "Lela", "Bruiser", and "Baloo") illustrate specific examples of anemia presentation, analysis, and conclusions.

Non-Regenerative Anemias

Includes anemia from insufficient/inadequate bone marrow responses due to decreased production.
Various causes like inflammatory diseases, endocrine diseases, chronic kidney disease, iron deficiency, toxins/infections, and bone marrow diseases also cause non-regenerative anemias.

Anemia of Inflammatory Disease (AID)

A commonly occurring, but usually mild, type of non-regenerative anemia associated with chronic inflammation, infection, or neoplasia; causes include sequestration of iron, decreased erythropoietin release, shortened RBC lifespan.
Typically characterized by mild normocytic/normochromic anemia.

Anemia of Endocrine Disease

Often mild, caused by decreased metabolic rate (like hypoadrenocorticism or hypothyroidism) and characterized by normocytic and normochromic anemia.

Anemia with Chronic Kidney Disease (CKD)

Variable anemia related to epo production problems and other correlated with CKD severity.
Characterized by inappropriate concentrated urine and other laboratory findings.

Iron Deficiency Anemia

Can be caused by physiologic reasons in young animals, chronic blood loss, nutritional issues (rarely in animals).
The anemia can be initially regenerative but often transitions to non-regenerative. Anemia can appear normocytic/macrocytic, and normochromic/hypochromic,
Associated with findings such as hypochromic, microcytic RBCs, thrombocytosis, and hypoproteinemia.

Iron Kinetics

Control of iron stores relies on total body stores and absorption rate.
Iron is absorbed by enterocytes, stored in ferritin, transferred by transferrin, and stored in macrophages in the liver, spleen, and bone marrow.

Iron Measurement

Serum Iron: iron bound to transferrin.
Total Iron-binding Capacity (TIBC): measures the capacity of transferrin to bind iron.
Transferrin Saturation: measures the percentage of transferrin bound to iron.
Ferritin: reflects total body iron stores, including values found in the blood (species-specific).
Bone marrow iron stores: gold standard, but invasive.

Iron Tests Overview

Diagnostic methods for iron, their significance and limitations
Includes tables illustrating the role of inflammation in affecting iron tests.

Non-regenerative Anemia: Infectious Causes

Anemia related to various infectious agents—FIV, Cytauxzoon felis, FeLV (often associated with macrocytosis), neoplasia, aplastic anemia in cats.
Also related to diseases such as equine infectious anemia (EIA) and Ehrlichia canis in dogs—associated with other clinical findings that help narrow down the diagnostics.

Non-regenerative Anemia: Aplastic Anemia

Bone marrow failure resulting in a decrease of all types of blood cells (pancytopenia).
Can be caused infections, drugs, toxins, radiation, and idiopathic causes.

Non-regenerative Anemia: Myelophthisis

Involves crowding out of bone marrow cells, frequently associated with neoplasia (cancer) and characterized by decreased blood cells.
Can present as anemia, thrombocytopenia, and/or leukopenia and is often indicated by specific morphology findings on a blood smear.

Non-regenerative, Immune-Mediated Anemia

Mild to severe non-regenerative anemia.
Immunological targeting of RBC precursors in bone marrow, sometimes with spherocytes in peripheral blood.
Can be seen with various immune-related diseases in both cats and canines.

Questions

Complete the eLC pre-lab assignment.
Prep for the anemia lab on Monday.

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Description

Test your knowledge on the various types of anemia and the characteristics of red blood cells. This quiz covers key concepts such as rubricytosis, microcytic anemia, and the diagnostic role of reticulocytes. Perfect for students in medical or veterinary programs keen on understanding hematology.