33. Bleeding disorders (coagulopathies, thrombocytopenia and thrombocytopathy) Flashcards
General conditions and Lab D of bleeding disorders?
Primary Haemostatic disorders?
Primary Haemostatic Disorders
Includes thrombocytopaenia, thrombocytopathy & vascular disorders
Clinical signs
“Superficial bleeding”
§ Petechiae § Epistaxis
§ Ecchymosis § Melena
§ Haematuria
Lab. D
§ ↑ Bleeding time
§ ↑/- Clot retraction (shrinking of blood clot)
§ ↓/- Platelet count
Thrombocytopenia in general?
THROMBOCYTOPAENIA IN GENERAL
Caused by ↓ platelet count
Congenital thrombocytopaenia
Hereditary macrothrombocytopaenia
Seen in cavalier King Charles Spaniel
Cyclic haematopoiesis
Seen in grey collies
§ 12-day cycles of cytopaenia → Excessive bleeding → Fatal
Acquired thrombocytopaenia
§ Consumptive thrombocytopaenia: Massive haemorrhages
DIC
§ Destruction thrombocytopaenia: Immune-mediated
§ Sequestration of thrombocytes in splenomegaly
§ ↓ Production of thrombocytes
Drugs (chemotherapy); Primary BM disorders
Immune- Mediated thrombocytopenia?
IMMUNE-MEDIATED THROMBOCYTOPENIA
Immune-mediated destruction of platelets & BM megakaryocytes
Predisposed: Females > Males; Cocker spaniel. Old English sheep
dogs
Clinical signs
§ Petechiae of skin/gingivae § Ecchymosis
§ Superficial bleeding § Melena
§ Splenomegaly § Epistaxis
Diagnosis
§ Lab. D: ↓ Platelet count <25g/l
§ Bone marrow aspiration
§ Exclusion of other factors
§ Drug-induced thrombocytopaenia
§ Tick-borne diseases
§ Viral infection
§ DIC
Treatment
§ Stop any immediate bleeding
§ Immunosuppression: Prednisolone; Vincristine
§ Recurrent cases: Splenectomy
Thrombocytopathy in general?
THROMBOCYTOPATHY IN GENERAL
Caused by ↓ platelet function
Hereditary thrombocytopathy: Von Willebrand’s disease
Acquired thrombocytopathy
§ Viral cause (FeLV) § Neoplasia
§ Nephropathy § Hepatopathy
§ Hypothyroidism § Lupus
§ Myeloproliferative disease § Drug
Von williebrands disease?
THROMBOCYTOPATHY - VON WILLEBRAND’S
DISEASE
Deficiency/absence of von Willebrand factor
Most common bleeding disorder in dogs (but also seen in cats)
Three subtypes:
Type I Mild/moderate CSx; Most common
Type II Moderate/severe CSx; Low vWF conc.
Type III Most severe CSx; Ø vWF at all
Clinical signs
See “Clinical signs” under “Primary haemostatic disorders”
§ Perinatal mortality
§ Stillbirth
§ Prolonged surgical bleeding
DIAGNOSIS
Lab. D
§ ↑ BMBT (buccal mucosal bleeding time)
§ ↑ Clot retraction; ↑/-ACT; ↑/-APTT
§ Low concentration of plasma vWF
DNA screening
TREATMENT
§ Fresh plasma transfusion – Giving desmopressin to the
donor may ↑ vWF in the plasma
§ Desmopressin acetate may be used for type I
VASCULAR DISORDERS
§ Vasculitis
§ Hyperadrenocorticism (Cushing’s)
Draw the Coagulation cascade?
Secondary Haemostatic disorders?
Clinical signs
“Deep bleeding”
§ Hemoperitoneum § Haemothorax
§ Hemarthrosis § Haematoma
Lab. D
§ ↑ Clotting time
§ ↑ Activated clotting time (ACT)
§ ↑ Activated partial thromboplastin time (APTT)
§ ↑ Prothrombin time (PTT)
Congenital coagulopathies
Usually deficits of a single coagulation factor; German Shepherd,
Golden retriever & Scottish terrier
§ Factor deficiency in an individual (idiopathic)
§ Devon Rex cat (vit. K dependant factors)
§ Factor VIII deficiency (haemophilia A) (dogs & cats)
§ Factor IV deficiency (haemophili B)
Acquired coagulopathies
Usually a combination of defects
↓ Factor production
§ Rodenticide poisoning
§ Hepatopathy (location of factor production)
§ Vit. K deficiency (by fat malabsorption, lymphangiectasia,
villous atrophy or rodenticides)
Vit. K factors: II; VII; IX; X
Rodenticide poisoning?
RODENTICIDE POISONING
Dicoumarol-type rodenticides – Competitive antagonists of the Vit. K coagulation factors (see above) e.g Warfarin
Clinical signs
Can take up to 24 hours to occur - treat even if asymptomatic
§ Acute collapse § Shock
§ Dyspnoea § Anaemia
§ Haemothorax § Coughing
§ Bleeding gums § Epistaxis
§ Petechiae § Haematoma
§ Bruising
Diagnosis
§ History: Access to poison, rodents; State of any other pets
§ Lab. D: ↑ PTT; APTT; ACT
Treatment
§ Treat for shock: Fluids; Plasma
§ Fresh whole blood; Fresh frozen plasma
§ Vitamin K1
§ If the poison was swallowed within the last 2-3 hours
Emetic + stomach rinse
Activated charcoal
Vit. K1
Other clotting disorders?
Other Clotting Disorders
§ Rickettsia spp. infection
§ Neoplasia
§ Vaccine-induced thrombocytopaenia
§ Drug-induced thrombocytopaenia
DIC?
DIC
Disseminated intravascular coagulopathy
Coagulopathy + thrombocytopenia
Pathogenesis
Excessive systemic intravascular coagulation → Multiple-organ
microthrombosis → Inactivation & consumption of platelets &
clotting factors → Paradoxical bleeding
Causes
§ Shock § Pancreatitis
§ Acidosis § Hemangiosarcoma
§ Hypoxia § Heat stroke
§ Infection § Burns
§ Trauma
Clinical signs
Frequently subclinical
§ Organ failure
§ Superficial/deep bleeding
Diagnosis
§ History of diseases causing severe inflammation/infection
§ Thrombocytopaenia; Schistocytosis
§ ↑ACT; ↑APTT; ↑PTT; ↑FDP; ↑D-dimer; ↓ Fibrinogen
Treatment
§ Treat underlying cause
§ Fresh whole blood; Fresh frozen plasma
§ Heparin (after transfusion)
§ Crystalloids; Plasma expanders
§ Oxygen therapy
§ Correction of any acidosis
