AG MED - Hematopoietic Disorders 1

Question 1

Regenerative anemia is characterized by ____ in ruminants and camelids.

Answer 1

Reticulocytes and uncleared RBCs

Question 2

Increased MCV indicates ____.

Decreased MCV indicates ____.

Answer 2

MCV = Mean corpuscular volume / average RBC volume
Increase —> regenerative anemia
Decrease —> iron and copper deficiency OR healthy calves

Question 3

What do increased/decreased MCHC indicate?

Answer 3

MCHC = mean corpuscule [Hgb] / Hgb per RBC

Increase —> typically false due to hemolyzed, icteric, or lipemic samples)

Decrease —> iron deficiency anemia

Question 4

Definition of anemia and two sequelae.

Answer 4

Absolute decrease in circulating RBCs

1. Inadequate oxygen transport
2. Interference with organ function

Question 5

Differentiate hemoglobinuria and Hematuria.

Answer 5

Hemoglobinuria
- Plasma reflects hemolytic state with possible development of icterus
- deep red to black urine
- throughout urination

Hematuria
- Blood in urine
- Red/pink/brown
- RBCs seen on microscopic exam
- Beginning (urethra, Repro tract); End (bladder); throughout urination (kidney, ureters)

Question 6

What is anaplasmosis?

Answer 6

Vector-borne
Infectious
Hemolytic
Rickettsial disease

Question 7

Anaplasmosis

Vectors:
Geographic location:
Reservoir:
Season:
Incubation:
Primary exposure:
Other species:

Answer 7

Vectors: tick borne - dermacentor, biting flies, mechanical vectors

Geographic location: 40 + states

Reservoir: Asymptomatic cattle

Season: Late spring through summer

Incubation: 15-30 days

Primary exposure: calfhood; less severe in calves up to 9 mo.

Other species: sheep (typically subclinical); goats (rare, severe anemia); camelids (rare anemia)

Question 8

When are clinical signs seen with anaplasmosis?

Answer 8

CS highly variable
Seen with 35-50% decrease in RBC

Question 9

Describe acute cases of anaplasmosis.

Answer 9

Develop over 4-9 days
Pyrexia (103-106 F); wanes over 12-24 hours; subnormal temp at death
Anorexia, lethargy, decreased milk production
Anemia
Pale, then icteric (if survives) mm
+/- dark brown feces, pollakiuria
Abortion

• DO NOT SEE HEMOGLOBINURIA

Question 10

Best way to definitively diagnose anaplasmosis.

Answer 10

Serology - ELISA; high sensitivity and specificity

Microscopic Eval difficult
PCR - typically seroconversion in acute dz

Question 11

Clin path for anaplasmosis

Answer 11

ID on blood smear

Rapid PCV drop (24-48 hrs) - death @ < 20%

Gradual PCV drop - death @ <10%

May see RBC regeneration in chronic cases

Question 12

Treatment for acute cases of anaplasmosis

Answer 12

Oxytetracycline - does not eliminate persistent infection

Supportive care - whole blood transfusion

PCV < 8% = poor prognosis

Question 13

Prevention of anaplasmosis

Answer 13

Vaccinate endemic areas with low transmission rates (killed experimental vaccine)

A. marginale-free herd in non-endemic areas —> quarantine and serological screening

Question 14

With chronic blood loss, physiologic adaptation masks signs until when?

Answer 14

PCV < 15%

Question 15

6 common causes of chronic blood loss

Answer 15

Bleeding GI lesions
Haemonchus
Anaplasmosis
Ticks
Hemostatic dysfunction
Renal disease

Question 16

Clinical signs of chronic blood loss

Answer 16

Ill thrift
Poor body condition
MM pallor
Edema (protein/albumin loss)
Weakness, lethargy

Question 17

8 common causes of acute blood loss

Answer 17

Epistaxis
Surgery
Ruptured liver/spleen/lung
Large vessel bleed
Clotting defect
Gastric ulcer
Hemoperitoneum
Hemothorax

Question 18

Clinical signs of acute blood loss

Answer 18

May or may not have obvious source

Hypovolemic shock
- tachycardia
- tachypnea
- cold extremities
- pale MM
- muscle weakness
- eventual death

Question 19

Clin path / DX for acute blood loss

Answer 19

Change in PCV/TP (several hours)
Ultrasound
Abdominocentesis / thoracocentesis

Question 20

Treatment for acute blood loss

Answer 20

Stop hemorrhage
Treat hypovolemic shock
- shock rate, isotonic crystalloids (40-80 mL/kg)
- hypertonic saline (2-4 mL/kg); 1-2 L for an average cow
- whole blood transfusion

Question 21

When does hemorrhagic shock occur?

Answer 21

At 30% of total blood volume lost

Question 22

How do you calculate total blood volume?

Answer 22

8% of total body weight (kg)

Question 23

A single unmatched transfusion is generally safe in ruminants. What are signs of transfusion reactions?

Answer 23

Tachypnea
Tachycardia
Dyspnea
Restlessness
Defecation
Piloerection
Muscle fasciculations

Question 24

Treatment for whole blood transfusion reactions

Answer 24

Epinephrine .01-.02 mL/kg 1:1000 IM

Flunixin meglumine 1.1 mg/kg IV

Question 25

Two components of hemostasis

Answer 25

Coagulation
Fibrinolysis

Question 26

Hemophilia A is an inherited hymostatic dysfunction affecting which factor?

Answer 26

VIII

Question 27

Factor ___ Deficiency is an autosomal recessive hemostatic dysfunction.

Answer 27

XI

Question 28

Name an acquired hemostatic dysfunction.

Answer 28

Sweet clover toxicosis

Question 29

Clinical signs of sweet clover toxicosis

Answer 29

• epistaxis and melena (early)
• stiffness and lameness
• death by massive hemorrhage

Question 30

Sweet clover toxicosis DFDX

Answer 30

DIC
Brackenfern toxicosis
Mycotoxicosis

*herd vs individual issues

Question 31

Sweet clover toxicosis clin path

Answer 31

• prolonged PT
• +/- Hematuria
• NORMAL platelet count (differentiates from DIC and brackenfern toxicosis)

Question 32

Sweet clover toxicosis treatment

Answer 32

Vitamin K
Whole blood transfusions for severe loss

Question 33

Sweet clover toxicosis geographic location

Answer 33

Northern plains states
- Idaho
- Montana
- Wyoming
- North Dakota
- South Dakota

Question 34

Sweet clover toxicosis pathogenesis

Answer 34

Moldy sweet clover hay/silage containing dicoumarol (20-30 mcg/kg hay over several weeks)

Interferes with hepatic synthesis of clotting factors II, VII, IX, X by inhibiting vitamin K

Same as warfarin toxicosis