Approach to bleeding patient (Yr 3)

Question 1

how much blood loss can most healthy dogs/cats withstand?

Answer 1

15-25%

Question 2

what are the possible life threatening situations to identify when presented with a bleeding patient?

Answer 2

hypovolaemic shock
severe anaemia
brain/pulmonary haemorrhage

Question 3

what should be done to stabilise a patient?

Answer 3

control haemorrhage
fluid replacement

Question 4

what type of fluid should be used for volume replacement in hypovolaemic animals?

Answer 4

crystalloids

Question 5

what is the shock rates of fluid replacement therapy?

Answer 5

fifth of the of normal blood volume
(20-90ml/kg in dogs)

Question 6

are shock rates or small volume resuscitations better?

Answer 6

small volume resuscitations

Question 7

what are the figures for small volume resuscitation?

Answer 7

dogs 10-20ml/kg
cats 5-10ml/kg
(over 15 minutes)

Question 8

what are the basic steps of haemostats?

Answer 8

vessel injury
vascular contraction
primary haemostasis
secondary haemostasis
tertiary haemostasis

Question 9

what is primary haemostasis?

Answer 9

formation of a platelet plug
this is dependant on platelets, von Willebrand factor and endothelium (collagen)

Question 10

what is the function of von Willebrand factor?

Answer 10

allows platelets to bind to themselves and the endothelium to form a platelet plug

Question 11

what is secondary haemostasis?

Answer 11

coagulation cascade that leads to generation of thrombin and allows a clot to form

Question 12

what is tertiary haemostasis?

Answer 12

fibrinolysis ensures the clot doesn’t get too big

Question 13

what are the clinical signs of a defect in primary haemostasis?

Answer 13

small holes (petechiae)
epistaxis and melaena

Question 14

are defects of primary or secondary haemostasis more severe?

Answer 14

secondary (larger hole formation) often present as life threatening blood loss such as pulmonary haemorrhage or cavity bleeding

Question 15

where should you take a blood sample if you are concerned about a clotting disorder?

Answer 15

peripheral vein (not jugular as bleeding will be hard to stop from there)

Question 16

what has to be excluded before doing a buccal mucosal bleeding time test?

Answer 16

thrombocytopenia (decreased platelets)

Question 17

what tests can be run for a primary coagulopathy?

Answer 17

manual platelet count
buccal mucosal bleeding time
von Willebrand factor

Question 18

what is a buccal mucosal bleeding time test designed to determine?

Answer 18

platelet function (should have normal clotting time and platelet count before doing this test)

Question 19

what tests can be run for testing secondary coagulopathy (clotting disorders)?

Answer 19

prothrombin time (PT)
activated partial thromboplastin time (APTT)
specific factor levels

Question 20

what are the main disorders of primary haemostasis?

Answer 20

thrombocytopenia
von Willebrand disease
(thrombocytopathia, vascular disease)

Question 21

what can general causes of thrombocytopenia?

Answer 21

lack of production
increased consumption
increased destruction
increased sequestration
spurious (clot in the tube)

Question 22

what can cause a thrombocytopenia due to lack of production?

Answer 22

bone marrow disorders
drug toxicosis (antibiotics, phenobarbitone…)

Question 23

what can cause a thrombocytopenia due to increased consumption?

Answer 23

DIC (disseminated intravascular coagulation)
acute severe haemorrhage

Question 24

what is a spurious cause of thrombocytopenia?

Answer 24

clot in the tube (lab error)

Question 25

what breeds are associated with inherited thrombocytopenia?

Answer 25

CKCS
sighthounds
(don’t need to be treated)

Question 26

what is the main cause of thrombocytopenia due to increased destruction?

Answer 26

immune mediated (primary or secondary)

Question 27

what can cause secondary immune mediated thrombocytopenia?

Answer 27

drugs - antibiotics
neoplasia
infectious disease - babesia, leptospirosis, leishmania, anaplasma

Question 28

how is primary immune mediated thrombocytopenia treated?

Answer 28

glucocorticoids (prednisolone)

Question 29

what is used to test for platelet function?

Answer 29

buccal mucosal bleeding time

Question 30

what is von Willebrand disease?

Answer 30

inherited deficiency in von Willebrand factor

Question 31

what breed is predisposed to von Willebrand disease?

Answer 31

dobermans

Question 32

when should you suspect von Willebrand disease?

Answer 32

any dog with mucosal surface bleeding or excessive bleeding following surgery or trauma

Question 33

what type of test is used to diagnose von Willebrand disease?

Answer 33

antigenic testing
(can do genetic testing)

Question 34

how is von Willebrand disease treated?

Answer 34

cryoprecipitate (concentrated solution of factor IIX, fibrinogen and von Willebrand factor)
can also give whole blood or fresh frozen plasma

Question 35

what are the most common causes of disorders of secondary haemostasis (clotting deficiencies)?

Answer 35

vitamin K antagonism/deficiency (rodenticide toxicity)
severe liver disease
DIC
inherited - haemophilia A and B

Question 36

what is the most common cause of vitamin K deficiency?

Answer 36

rodenticide toxicity

Question 37

what are the typical clinical signs of vitamin K deficiency?

Answer 37

epistaxis, melaena, haematoma, ecchymoses, haematuria, gingival bleeding

Question 38

what should be done to diagnose vitamin K deficiency?

Answer 38

coagulation testing (PT/APTT)
clinical history/signs

Question 39

what is DIC?

Answer 39

disseminated intravascular haemolysis - activation of clotting cascade forming lots of small clots which then exhausts the platelets or clotting factors leading to bleeding

Question 40

what can cause DIC?

Answer 40

septicaemia
immune mediated disease
neoplasia
heat stroke

Question 41

what abnormalities on laboratory testing will be seen in cases of acute DIC?

Answer 41

prolonged clotting times
thrombocytopenia
schistocytes (clots blocking vessels)
decreased fibrinogen
increased D-dimers

Question 42

what are D-dimers?

Answer 42

products of the breakdown of clots (fibrin)