TV4101 - Haemostasis 3

Primary Haemostasis - Broad issues

PLT #?

PLT #

Primary Haemostasis

Cause affecting PLT # i.e. Thrombocytopaenia

Causes? In what way?

Primary Haemostasis

Cause affecting PLT # i.e. Thrombocytopaenia

Immune version aka?

Prevalence in who?

Severity?

#PLT?

Immune mediated thrombocytopenia (IMT)

Platelet destruction

Common in dogs, but also documented in cats & horses

Severe thrombocytopenia

< 3 platelets /hpf (100x)

Primary Haemostasis

Cause affecting PLT # i.e. Thrombocytopaenia

Bracken Fern (Ruminants)

What do we see physically in calves?

Primary Haemostasis

Cause affecting PLT # i.e. Thrombocytopaenia

Diseases in ruminants?

What are their respective blood profiles?

Primary Haemostasis

This cow had vulvar haemorrage

What do we suspect?

Bracken poisoning

Primary Haemostasis

Cause affecting PLT # i.e. Thrombocytopaenia

Ruminants

How does this relate to food?

Poorly stored grain can lead to contamination with

trichothecene mycotoxins

Primary Haemostasis

Cause affecting PLT # i.e. Thrombocytopaenia

Ruminants

What can we see?

Suspected dz?

Epistaxis from thrombocytopaenia

Bleeding calf syndrome/Bovine neonatal pnacytopaenia

Primary Haemostasis

Cause affecting PLT # i.e. Thrombocytopaenia

Bracken Fern

What does it cause?

Acute haemorrhagic syndrome ass. with leukopaenia, thrombocytopaenia and anaemia

Bovine enzootic haematuria with severeal urinary bladder tumours

Primary Haemostasis

VWD

Function of vWB factor?

1. Platelet adhesion

- damaged blood vessels

- Platelets to each other

2. Stabilising & protective carrier molecule

Primary Haemostasis

VWD

What does it causein terms of blood cells? What way?

Thrombocytopaenia - abnormal PLT function from vWF deficiency

Primary Haemostasis

VWD

Prevalence?

Most common hereditary bleeding disorder in dogs

Rare in cats, horses & cattle

Primary Haemostasis - Which breeds are most commonly affected by VWD? List a few

Poodle

GSD

Corgi

Doberman

Golden Retriever

Rough collie

Primary Haemostasis - VWD

Diff types, severity and breeds?

Primary Haemostasis - VWD

CX?

Prolonged haemorrhage from nonsurgical or surgical trauma

Dogs: usually present at young age with excessive bleeding with teething or spaying/neutering

Primary Haemostasis - VWD

Pattern of haemorrhage?

Primary Haemostasis - VWD

Lab signs?

2ndary Haemostasis

Acquired defects?

PT and APTT features?

2ndary Haemostasis

Inherited Aspects and their respective PT or APTT changes

Factor VII def - Prolonged PT

Factor XII, XI, IX, VIII deficiency - Prolonged APTT

Factor X, Factor V, prothrombin, fibrinogen or combined factor deficiency - Prolonged PT & APTT

2ndary Haemostasis - Inherited Haemophilia

Types?

Signalment?

What happens?

DX tests?

Haemophilia A (factor VIII def)

Haemophilia B (factor IX def

Male (female carriers)

Spontaneous bleeds

- bleeding into body cavities

- haematomas

- haemarthroses

- epistaxis

Diagnostic tests

- Prolonged ACT & APTT

2ndary haemostasis - Acquired coag factor deficiencies (usually multiple factors)

Includes?

2ndary haemostasis - Acquired coag factor deficiencies (usually multiple factors)

DX tests? In which order?

Increased PT (first) & then APTT

2ndary haemostasis - Acquired coag factor deficiencies (usually multiple factors)

Anticoagulant Rodenticides

How does it work?

1. Vit K absent/antagonised by poison → Vit K needed to carboxylate/activate factors II, VII, IX, X → Can’t be activated → Relative factor def due to inactivity

2. Carboxylation of these clotting factors is necessary to bind phospholipid membrane

   surfaces in a Ca2+-dependent manner

2ndary haemostasis - Acquired coag factor deficiencies (usually multiple factors)

Anticoagulant Rodenticides (Vit K antagonism)

The different types, time to take effect and examples

Hydroxycoumarins

• First gen - 1 wk to take effect (Multiple doses needed)

  • Warfarin

  • Coumafuryl

• 2nd gen - 4-6wks to take effect (Single dose or eat rat that ate poison)

  • Brodifacoum

  • Bromadiolone

Indandiones

• Similar to 2nd gen

• Diphacinone and Chlorophacinone

2ndary haemostasis - Acquired coag factor deficiencies (usually multiple factors)

Anticoagulant Rodenticides

Basic Overview

2ndary haemostasis - Vitamin K deficiciency

Significance?

Describe Vit K behaviour?

Deficiency with?

(usually multiple factors def, rarely deficient enough to cause haemorrhage)

Vitamin K is fat soluble - need bile (liver), functioning GIT and Pancreas

• Cholestatic hepatopathy

• GIT pathology (fat malabsoption/maldigestion)

2ndary haemostasis - Vitamin K deficiciency

What tests are done?

2ndary haemostasis - Acquired coag factor deficiencies (usually multiple factors)

Liver Dz

Liver disease can result in haemostatic disease due to?

1. Cholestatic hepatopathy (Vit K def)

2. Acute or fulminant liver disease ending in DIC

3. Coagulation Factor Deficiencies

2ndary haemostasis - Acquired coag factor deficiencies (usually multiple factors)

Liver Dz

Bleeding aspect?

Cat bleeding aspects?

Tests for dog?

Bleeding uncommon but can occur with severe liver disease

Cats with major complications – association with APTT > 1.5 x mean of reference interval

Predicative value of haemostatic tests for bleeding during biopsy in dogs not good

2ndary haemostasis - Acquired coag factor deficiencies (usually multiple factors)

Liver Dz

Even though bleeding is uncommon for liver dz, Bleeding complications in dogs & cats – more strongly associated with ?

What else can be abnormal in liver dz?

Thrombocytopenia than prolonged PT & APTT

Platelet number or function can also be abnormal

2ndary haemostasis - Acquired coag factor deficiencies (usually multiple factors)

Liver Dz

Tests to determine risk of blleding complications in dogs with chronic hepatitis? What are the high risk values?

2ndary haemostasis - Acquired coag factor deficiencies (usually multiple factors)

Liver Dz

Lab tests

Coagulation panel shows? What does this mimic?

Thrombocytopenia

Thrombocytopathy

Prolonged BMBT

Prolonged PT, APTT, ACT,

TT prolonged [fibrinogen - decreased]

Increased FDP &/or D-dimer

Can mimic consumptive coagulopathy/DIC

2ndary haemostasis - Acquired coag factor deficiencies (usually multiple factors)

DIC

aka?

How does it occur?

Disseminated intravascular coagulation

Always secondary to another disease process - trigger

2ndary haemostasis - Acquired coag factor deficiencies (usually multiple factors)

DIC

How does it work?

2ndary haemostasis - Acquired coag factor deficiencies (usually multiple factors)

DIC

What tests are done?