Disorders of Haemostasis Flashcards
Define haemostasis
Stopping of the flow of blood
3 stages of haemostasis
Primary Haemostasis: Formation of platelet plug
Secondary Haemostasis: Stabilisation of platelet plug (Fibrin formation)
Tertiary Haemostasis: Breakdown of platelet plug
What is the function of von williebrand factor
Involved in the tethering platelet to vascular wall involved in primary haemostasis
What is the name and function of the protein most involved in tertiary haemostasis
Plasmin. Breaks down crosslinked fibrin to fibrin degradation products
List common disorders of primary haemostasis
Thrombocytopenia
Thrombocytopathia (Platelet dysfunction)
Von Willebrand’s disease (Congenital)
Vasculopathies
List common disorders of secondary haemostasis
Anticoagulant rodenticide toxicity
Liver failure
Congenital factors e.g. Haemophilia
Haemophilia
Congenitial disease that affects clotting
What is the most common congenitial bleeding disorder in german shepards
Hemophilia A/Factor VIII Deficiency is an inherited bleeding disorder in German Shepherd Dogs and related breeds caused by a deficiency of the coagulation factor VIII (F8), a protein necessary for blood clotting.
What is the most common congenital bleeding disorder in doberman pincher
Von Willebrand Disease (vWD)
What are common clinical findings of thrombocytopenia
Petechiation
Ecchymosis
GI bleeding causing melaena
Clinical signs associated with anemia
Petechiation
pinpoint, reddish or purplish spot containing blood that appears in skin or mucous membrane as a result of localized hemorrhage
Ecchymosis
Broad localised bruises
Melaena
Blood in faeces
List laboratory assessment for primary haemostasis
Platelet count
BMBT (Buccal mucosal bleeding time)
Activated clotting time
What are common clinical findings of Von Willebrand Disease
Excessive bleeding at surgical sites
Prolonged bleeding at oestrous
What are common clinical findings of coagulopathies
Haematoma formation
Pulmonary haemorrhage
Bleeding into body cavities
List laboratory assessment for secondary haemostasis
Standard coagulation test:
Prothrombin time
Activated partial thromboplastin time
Fibrinogen
Activated clotting time
List laboratory assessment for tertiary haemostasis
Fibrin degradation products
Causes of thrombocytopenia
Immune mediated thrombocytopenia
Bone marrow failure
Infectious disease (Anaplasmosis/Ehrilichosis)
Increased consumption (Severe blood loss)
Breed variation
Cocker spaniels are predisposed to have what haemostatic disorder?
Immune mediated thrombocytopenia
How is immune mediated thrombocytopenia diagnosed
Diagnosed by exclusion
Clinical signs include surface/capillary bleeding (Primary haemostatic disorder)
Low platelet count
Management of Immune mediated thrombocytopenia
Gentle handling
Blood transfusion if anemic enough
Treatment of underlying trigger if secondary
Immunosupression
Vincristine to increase number of circulating platelets
Diagnosis of anticoagulant rodenticide toxicity
History of potential exposure
Lab test for secondary haemostatic disorders
Increased prothrombin time
Treatment for anticoagulant rodenticide toxicity
<6 hours: emesis (vomitting), monitoring PT
Vit K1
Supportive care
Clinical signs for liver disease
Coagulopathy: Cavity bleeds
Increased risk for bleeding with biopsy
How does liver disease affect haemostasis
Failute to absorb Vit K1
Reduced production of clotting factors
Reduced acitvation of vitamin K dependant factors
Which protein clotting time would you look at if confirming a diagnosis for liver disease
Prolonged prothrombin clotting time
Name the parasite that can cause haemostasis disorders
Angiostrongylus Vasorum (French Lungworm)
Lungworm diagnosis
Faecal Baermann’s test for L1 larvae (3-day pooled sample to increase sensitivity)
Faecal wet prep
In-house ELISA: IDEXX Angio Detect
Treatment for lungworm
Supportive care for haemorrhage (transfusion?)
Parasite kill
Imidacloprid/ moxidectin and milbemycin licenced in UK
Steroids: for ‘worm-kill’ effect
What is DIC
Disseminated Intravascular Coagulation
Dysfunction of the normal regulatory mechanisms of coagulation and fibrinolysis resulting in unregulated production of THROMBIN and self-perpetuating activation of coagulation and fibrinolysis.
Clinical signs of DIC
Mixture of thrombosis and bleeding
Treatment of DIC
Eliminating initiating cause
Ensuring adequate tissue perfusion
Supporting target organs susceptible to microthrombi, ischaemia or haemorrhage
Replacement of blood components
Thrombocytopathia
Platelet Dysfunction
Usually associated with an underlying disease process
Diagnosis of Thrombocytopathia
Normal PLT count and standard coagulation tests
Prolonged BMBT (Ddx von Willebrand’s Disease)
Oral petechiae in a cat could be caused by?
Primary coagulation disorders
Thrombocytopenia
Concurrent DIC could be a differential
PPT (activated thromboplastin time) determines which pathways?
Intrinsic and common pathway
PT (prothrombin time) determines which pathways?
Extrinsic and common
Prolonged PPT time with normal PT time suggest deficiency in which factors and what disease?
Factor 8 (VWD and haemophilia A)
Factor 9 (Haemophilia B)
Factor 11/12
Prolonged PT time with normal PPT time suggest deficiency in which factors and what disease
Factor 7 (DIC/Vit K antagonism)
What does Prolonged PT time and PPT time suggest
Vit K deficiency
Rodenticide toxicity
Excessive warfarin treatment
Liver disease
