L24: IMHA And Thrombocytopenia (Moyle)

Question 1

RBC membrane sustained by:

Answer 1

• anaerobic glycolysis
• maintaining ionic env.
• antioxidants
• resealing membrane if damaged

Question 2

Categories of hemolytic anemia

Answer 2

Intrinsic vs. extrinsic

IV vs. EV

Question 3

Intrinsic hemolysis

Answer 3

Secondary to defect w/n erythrocyte itself. Usually caused by inherited disorders

Question 4

Inherited disorders that cause intrinsic hemolytic anemia

Answer 4

Membrane-related (causing increased osmotic fragility)
Enzyme-related (Porphyria, Pyruvate kinase or phosphofructokinase deficiency)

usually autosomal recessive

Question 5

Pyruvate kinase deficiency

Answer 5

• PK needed in last step of ATP generation during glycolysis

- results in RBCs deficient in ATP –> defective membranes –> hemolysis

Question 6

Phosphofructokinase deficiency

Answer 6

• PFK is rate-controlling enzyme of glycolysis
• deficiency –> “alkaline fragile” RBCs due to decreased ATP
• exertional myopathy leads to hemolytic anemia

Question 7

Extrinsic causes of hemolytic anemia

Answer 7

1) Oxidative injury –> methemoglobinemia, Heinz body anemia, membrane injury, hypophosphatemia

2) Infectious (blood parasites)
3) Alloimmune
4) Microangiopathy
5) IMHA

Question 8

Drugs that cause methemoglobinemia

Answer 8

Acetaminophen

Benzocaine

Question 9

Drugs/food that cause Heinz body anemia

Answer 9

Acetaminophen
Benzocaine
Onions
Garlic

Question 10

Substances that cause membrane injury –> oxidative injury –> extrinsic hemolytic anemia

Answer 10

• zinc (pennies, sunblock, lotions)
• Cu
• Naphthalene

Question 11

Alloimmune causes of extrinsic hemolytic anemia

Answer 11

Neonatal isoerythrolysis

Transfusion rxn

Question 12

Microangiopathy causes of extrinsic hemolytic anemia

Answer 12

HWD
HSA
DIC

Question 13

Normal erythrocyte lifespan in dogs/cats

Answer 13

Dogs: 120 days
Cats: 70 days