33. Bleeding disorders (coagulopathies, thrombocytopenia and thrombocytopathy) Flashcards

1
Q

General conditions and Lab D of bleeding disorders?

A
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2
Q

Primary Haemostatic disorders?

A

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

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3
Q

Thrombocytopenia in general?

A

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

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4
Q

Immune- Mediated thrombocytopenia?

A

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

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5
Q

Thrombocytopathy in general?

A

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

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6
Q

Von williebrands disease?

A

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)

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7
Q

Draw the Coagulation cascade?

A
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8
Q

Secondary Haemostatic disorders?

A

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

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9
Q

Rodenticide poisoning?

A

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

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10
Q

Other clotting disorders?

A

Other Clotting Disorders

§ Rickettsia spp. infection

§ Neoplasia

§ Vaccine-induced thrombocytopaenia

§ Drug-induced thrombocytopaenia

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11
Q

DIC?

A

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

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