Immune Mediated

Question 1

Indications for Hemorrhagic or Fe deficiency Anemia

Answer 1

(everything possible, but not required)

• low MCV
• hypochromic
• schistocytes
• acanthocytes, codocytes

Question 2

Causes of fragmentation hemolysis

Answer 2

1. mechanical injury (DIC, caval syndrome, glomerulonephritis)
2. endothelial injury (hemangiosarcoma, vasculitis, splenic/hematic disease)
3. thermal injury (burns)
4. osmotic injury (near drowning)

Question 3

causes of oxidative RBC damage?

Answer 3

1. increased oxidants (drug/toxin)
   - acetaminophen, onion, garlic
2. decreased anti-oxidant (ATP depletion, congenital enzyme deficiency)

Question 4

Heinz bodies

Answer 4

oxidation of SH groups causes denaturation and precipitation

-> hemolytic anemia

Question 5

Indications of hemolytic anemia due to oxidative damage

Answer 5

regenerative anemia
heinz bodies
eccentrocytes and pyknocytes

Question 6

types of hemolytic anemias

Answer 6

1. IMHA
2. Erythroparasitism
3. Heinz body
4. RBC metabolic defects (Zn, decreased phosphatemia, envenomation, or congenital)

Question 7

Mechanism for most IMHA and ITP

Answer 7

Bcell/antibody (IgG, IgM)

Question 8

Causes of agglutination

Answer 8

• IMHA
• Rouleaux
• cold agglutinations are generally non-pathologic

Question 9

Hypophosphatemia

Answer 9

severely low (<1-1.5 mg/dL)
ATP depletion causing osmotic fragility and oxidative damage.
associated with insulin (DKA), feeding after starving, hypoparathyroidism

Question 10

Envenomation

Answer 10

contains phospholipases and hemolysins
- echinocytes, spherocytes, ghosts
- hemolysis
may have blood loss from tissue damage

Question 11

IMHA indications

Answer 11

regenerative anemia
agglutination
spherocytes, ghost cells
neutrophilia
monocytosis

Question 12

Evans syndrome

Answer 12

IMHA and ITP

Question 13

IMHA clinical signs

Answer 13

• fever
• organomegaly (spleen, liver, lymph nodes) (due to EMH)
• icterus (not every animal, depends on rate of destruction and how well liver can keep up)
• pigmentemia, pigmenturia, orange feces
• elevated coag times (if in DIC)

Question 14

Bilirubin
conjugated where?
how is it excreted?
why does IMHA cause icterus?

Answer 14

conjugated in liver
excreted in urine and feces

increased RBC turnover increased bilirubin, causing icteric urine and feces. Once excretory pathways are overwhelmed, you see icteric plasma then MM (when bili >2mg/dL)

Question 15

Intravascular hemolysis.

What happens to free Hb?

Answer 15

plasma becomes pink (hemoglobinemia)
Haptoglobin binds free Hb and transports it to liver for metabolism.
Hemoglobinuria occurs when haptoglobin is overwhelmed.

Question 16

Other transport molecules?

Why are they necessary?

Answer 16

Hemopexin (for heme)
Transferrin (for Fe)

Free Heme, Hb, Fe are toxic, so they need an escort. The chaperones consume NO which causes vasoconstriction and platelet clumping. RBC membrane lysis and inflammatory state are also apparent in IV hemolysis.

Question 17

Difference between IV and EV Hemolysis?

Answer 17

EV                /         IV
Acute to Chronic /    Acute
 Within MPS         /    Outside
conserves Fe, AA /    loses 
                         /      Greater risk of DIC, shock

Question 18

Cold Agglutination disease

Answer 18

weird neoplasia/ inflammatory conditions produce Ab that are active at colder temperatures (in the extremities)

Question 19

False negative on Coombs?

Answer 19

may indicate low antibody titer
technical issues
Cat
(not caused by immunosuppression or transfusion!)

Question 20

Primary IMHA signalment

Answer 20

Cocker Spaniel!

middle aged 2-7 yrs (not geriatric)

Question 21

IMHA relapse?

Answer 21

common after tapered off of immunosuppresion

Question 22

factors associated with worse prognosis with IMHA?

Answer 22

IV hemolysis
severe hyperbilirubinemia (>10mg/dL)

Question 23

Acute Zn Toxicosis

Answer 23

can look like IMHA (regenerative anemia, spherocytes, heinz bodies, inflammatory leukogram)

But are Coombs negative!
Hemolysis is due to Zn induced Ab binding and heinz body formation.

Question 24

Signalment for primary ITP

Answer 24

Cocker spaniel middle aged (same as IMHA) also poodles, sheepdog

Question 25

clinical signs ITP

Answer 25

- more likely when platelets <30k/uL - petechia, ecchymosis, bruising, epistaxis, GI hemorrhage, oral bleeding, vaginal bleeding - ocular bleeding or blindness - cerebral bleeding - hematuria - stiffness, lethargy, weakness, collapse - prolonged bleeding during estrous, surgery venipuncture

Question 26

Clin path changes in ITP

Answer 26

severe thrombocytopenia +/- increased MPV +/- concurrent anemia (blood loss or IMHA)

Question 27

hemorrhage/Anemia is likely a ______ of severe thrombocytopenia, not the _____

Answer 27

symptom; not the cause

Question 28

Treatment for ITP

Answer 28

same as IMHA = immunosuppressives | may add vincristine (causes release of more platelets)