Clinical Pathology 3: Bilirubin And Hemolytic Anemia

Question 1

Approximately 1% of RBC are destroyed and replaced daily. What does it mean when the rate is greater than 1%?

Answer 1

Hemolysis

Question 2

What is hemolysis

Answer 2

Processing of a RBC by a macrophage

Question 3

What are the two types of hemolysis

Answer 3

1. Extravascular
2. Intravascular

Question 4

Extravascular hemolysis

Answer 4

RBC destruction occurs outside of the blood vessels via phagocytosis by macrophages

Question 5

Intravascular hemolysis

Answer 5

RBC destructions occurs within the blood vessels.

Question 6

Hemoglobin from Intravascular hemolysis can result in what?

Answer 6

Injury to tissue (hemoglobinuric nephrosis)
- Must be scavenged by the body before damage occurs

Question 7

When a red blood cell is digested by a macrophage what is the waste product?

Answer 7

Unconjugated bilirubin

Question 8

Icteric

Answer 8

Jaundice

Question 9

What is haptoglobin?

Answer 9

The scavenging system for hemoglobin
— haptoglobin bind hemoglobins and takes it to the liver to be processed into billirubin

Question 10

What will the plasma and urine look like when hemoglobin<haptoglobin

Answer 10

Normal

Question 11

If there is more hemoglobin than haptoglobin What are the potential outcomes?

Answer 11

1. Hemoglobinemia
2. Hemoglobinuria

Question 12

What is hemoglobinemia?

Answer 12

Red plasma
- Intravascular hemolysis

Question 13

What is hemoglobinuria

Answer 13

Red urine from freely floating hemoglobin passing through the glomerulus into the urine
- From Intravascular hemolysis

Question 14

What is hyperbilirubinemia?

Answer 14

Too much billirubin in the blood from either Extravascular or intravascular hemolysis

Question 15

What is Bilirubinuria?

Answer 15

Presence of billrubin in the urine

Question 16

Causes of hemolysis

Answer 16

Infection, Oxidative injury, immune-mediated RBC destruction

Question 17

Hemolysis caused by infection: identification method

Answer 17

Blood smear: characteristic RBS parasites

Question 18

Hemolysis caused by infection: causes

Answer 18

Infectious agents (Ex: Anaplasma)

Question 19

Forms of hemolysis caused by infectious agents

Answer 19

Intravascular hemolysis: RBC membrane instability
Extravascular hemolysis: Splenic macrophage identifying infected cell and phagocytes

Question 20

Hemolysis caused by oxidative injury: Causes

Answer 20

• Ingestion of: garlic, onions zinc (dogs), Tylenol (cats), red maple leaves (horses), Copper( sheep and goats
• CRI of propofol

Question 21

Hemolysis caused by oxidative injury: diagnostic method

Answer 21

Blood smear:
- Heinz bodies
- Eccentrocytes
- Pyknocytes
- Ghost cells

Question 22

Hemolysis caused by Immune-mediated destruction: What happens?

Answer 22

Anti-RBC antibodies are formed and attach to surface of RBC.

Question 23

Hemolysis caused by Immune-mediated destruction: Results

Answer 23

• Complete phagocytosis by splenic and hepatic macrophages (EVH)
  -Partial phagocytosis by splenic and hepatic macrophages. Bites off part of RBA membrane —> sphere types (EVH)
  -MAC formation (IVH)

Question 24

Hemolysis caused by Immune-mediated destruction: causes

Answer 24

• Primary autoimmune
• Secondary autoimmune (due to drugs)
  — Penicillin in horses, phenobarbital
  -Alloantibodies

Question 25

What is an alloantibody

Answer 25

Where antibodies attack RBC
- Maternal antibodies via colostrum attack kitten/foal RBC
- Incompatible blood transfusion

Question 26

Hemolysis caused by Immune-mediated destruction: laboratory findings / Diagnosis method

Answer 26

Blood smear:
- Spherocytes (difficult to recognize on cats and horse as they have little central pallor)

Positive direct anti globulin test:
- recognizes Antibody on RBC surface

Question 27

Auto-agglutination

Answer 27

Immune-mediated anemia:
IgM autoantibody, cross links to other RBCs via antibody
-Strongly regenerative anemia

Question 28

Fasting hyperbilirubinemia

Answer 28

-Horses and Sm Ru
-Increased bilirubin bc hepatocytes are busy metabolizing Fat
- INcreased Unconjugated bilirubin