Diseases Associated with Blood Loss or Hemostatic Dysfunction

Question 1

A 10 year old Quarter horse gelding presents with a history of acute blood loss secondary to a distal limb laceration approximately 12 hours ago. The owners have been trying to control the bleeding with bandages and wraps. On presentation, the heart rate is 60 bpm, respiratory rate 30 breaths per minute and the temperature 38 C. The mucous membranes are pale pink and the capillary refill time is 2 seconds. There are decreased gastrointestinal boryborygmi. The PCV is 19% and TP 5.9 g/dl and the peripheral lactate is 3 mmol/L. The blood loss from the limb is stabilized. What would be your recommended emergency treatment for reversing the sequalae of severe hemorrhagic shock?

Answer 1

2-4 ml/kg of 7.2 % sodium chloride IV, followed by 40-80 ml/kg of isotonic crystolloids IV

Question 2

What peripheral signs of erythrocyte regeneration are characteristic of ruminant after hemorrhage?

Answer 2

Erythrocyte polychromasia
Basophilic stippling
Howell-Jolly Bodies
Occoasional Nucleated RBC (within 4 days of onset)

Question 3

What samples are used for the major and minor crossmatch?

Answer 3

Major cross match : Donor cells with recipient serum
Minor cross match: Recipient cells with donor serum

Question 4

If a ruminant blood donor is incompatible with the recipient serum, what is the typical finding from the crossmatch?

Answer 4

hemolysis

Cattle do not show agglutinins like the horse

Question 5

What is the estimated blood loss for a 500 Kg Holstein cow that had the PCV drop from 36% to 12 %?

Answer 5

27 liters of estimated blood loss

Assuming that 8% of the body weight is the blood volume

Question 6

How many liters of whole blood would you deliver to a 50 kg goat who was estimated to have lost 2 liters of blood? The goal is to sufficiently maintain life until the bone marrow responds.

Answer 6

400-800 ml

Estimated dose for replacing 20-40% of the losses.

Question 7

If a severe transfusion reaction occurs, what is the recommended emergency treatment?

Answer 7

epinephrine 0.01-0.02 mg/kg

Question 8

After an acute blood loss, when does the bone marrow normally begin to replace the lost cells?

Answer 8

5 days

Question 9

What are the most common causes of hemoperitonmeum in the horse?

Answer 9

• Splenic trauma
• reproductive tract and assoicated vessels
• neoplasia

Question 10

What breed(s) of horses from a recent retrospective study on hemoperitoneum were overrepresented?

Answer 10

Thoroughbreds and Arabians

Question 11

What typical clinicopathologic abnormalities are identified in cases of hemoperitoneum?

Answer 11

anemia and hypoproteinemia
neutrophilia, lymphopenia
thrombocytopenia
hypocacleumia and azotemia

Question 12

What is the typical PCV and TP of a hemorrhagic adbdominal effusion?

Answer 12

18% PCV
3.2 g/dl total protein

Question 13

What are the three most common causes of GI hemorrhage (chronic blood loss) in ruminants?

Answer 13

• abomosal lymphoma in cattle
• parasitism
• abomasal ulceration

Question 14

Which intestinal parasite of ruminants has been associated with significant hemorrahge shortly after anthlemtic treatment?

Answer 14

*Haemonchus contorus

Question 15

How would serum ferritin be expected to change in a ruminant with an increased total iron-binding capacity and a reduction in marrow iron?

Answer 15

It will be reduced. Hypoferremia will be present.

Question 16

What is the mechanism of disease for an NSAID associated right dorsal colitis?

Answer 16

NSAIDs inhibit cyclooxygenase (COX1>COX2) and inhibit prostaglandi E production, which can result in ishemic GI mucosal damage and delayed mucosal healing.

Question 17

What are the two interrelated components ( functions) associated with hemostasis?

Answer 17

• coagulation (arrest bleeding from damaged vessel)
• fibrinolysis ( keep blood vessels open to maintain nutrient flow)

Question 18

What are the key steps of coaugulation that occur when a blood vessel is damaged?

Answer 18

1. vasoconstriction
2. platets adherence to the subendothelial collagen
3. platelet membrane conformation change
4. platelet aggregation, contraction and granule secretion (basic platelet reaction)
5. Platlet phospholipoprotein (PF3) provides surface to catlyze interactions among activiated coag. proteins = thrombin formation

Question 19

The extrinsic coagulation pathway is initiated by what factor?

Answer 19

lioprotein tissue factor (TF) which is found widely distributed in most tissues

Question 20

How is the intrinsic coagulation pathway inititiated?

Answer 20

blood is exposed to a negatively charged surface (activated platelet)

Question 21

Both the intrinsic and extrinsic coagulation pathway culminate in the formation of what factor?

Answer 21

activated factor X (Xa) which leads to thrombin

Question 22

What is the primary physiological inhibitor of thrombin and Xa?

Answer 22

• antithrombin II (AT III)
• It provides 70% of the anticoagulant activity of plasma

Question 23

Which factors are inhibited by the protein C system?

Answer 23

Factor V and VIII

Question 24

What is the primary plasma protein responsible for fibrin degredation?

Answer 24

plasmin (plasminogen zymogen)

Question 25

What is the most important factor that determines the rate of fibrinolysis?

Answer 25

fibrin formation