Week 7- Approach to Coagulopathies Flashcards
What are the three phases of clotting?
- Initiation
- Amplification
- Propagation
What is DIC
when you stop clotting (clotting factors used up)
What is the clinical presentation of a bleeding patient?
blood disorder
- lethargy
- collapse
- tachycardia
- excessive bleeding
- pale mucous membranes
What does a secondary haemostasis bleed look like?
- Bigger bleed s
- Usually in body cavities
What is fibrinolysis?
- Fibrin breakdown
- Fibrin stabilises clot
- Mediated by plasmin
- release of FDP’s
What is Primary Hyperfibrinolysis
Delayed bleeding post trauma or minor
procedures
* 36-48 hours after the incident * Greyhounds
* Normal coagulation parameters
What is secondary hyperfibrinolysis?
Due to systemic hypercoagulability –
first stages of DIC
What is secondary hypofibrinolysis?
Late DIC
* Impaired fibrin structure
(dysfibrinogenaemia) * Impaired fibrinogen production – liver * Congenital fibrinogen deficiency
* Excessive fibrinogen loss – large blood
loss
* Iatrogenic – anti-fibrinolytic therapy
Why does heat stroke cause bleeding disorders?
they go into DIC due to the inflammatory process that has been triggered
What in house diagnostic tests might you do?
- Blood smear
- PCV/TS
- BMBT
What out of house diagnostic tests might you do?
Haematology
* Serum chemistry – may include liver function tests
* Clotting times (coagulation profiles)
* FDPs; D-dimers; fibrinogen levels
What specific tests might you do?
Hereditary conditions (ELISA for vWF)
* SNAP 4DX – anaplasmosis, ehrlichiosis,
dirofilariasis, borreliosis
What platelet counts should you be seeing?
look for > 10 platelets per field of monolayer cells under 100x oil immersion (Dog 8-15; Cat 10-12)
* Count 10 fields and get average per field
* < 2-3 per field = thrombocytopaenia and spontaneous bleeding
* Estimated count/μL = average x 15 000
* < 20 000 – 50 000/μL = spontaneous bleed
What is Buccal mucosal bleeding time (BMBT)
Test of platelet and vessel function
* Indicated if suspect primary haemostatic defect despite normal platelet number
* Normal: 2 - 4 min dog / 1 - 2.5 min cat
What is the procedure for buccal mucousal bleeding time
Conscious animal (may need sedation)
* Lateral recumbency, minimal restraint
* Upper lip folded back and held with gauze bandage
* Incision in non-vascular area
* Filter paper used to absorb the blood
* Time from incision to cessation of bleeding recorded
What are the platelet tests?
Blood smear with platelet count and evaluation
* PCV/TP
* Maybe BMBT
* (Thrombocytopaenia, thrombocytopathy, von Willebrand’s disease)
What are the clotting tests?
Prothrombin time (PT) – Extrinsic and common pathway – Factor VII
* Activated Partial thromboplastin time (aPTT) – Intrinsic and common
pathway – XII, XI, IX,VIII
* (Liver disease, Vit K antagonism, Haemophilia, DIC)
What tests would you do if fibrinolysis is suspected?
FDPs (DIC, blood clots, liver not clearing FDPs)
* D-dimer (DIC, recent blood clots – within previous 5h, neoplasia)
What factor has the shortest half life
- factor 7
- will most likely run out first
also has no storage pools
What tube is used for the blood?
Citrate tube- blue- avoids TF from tissue
What is vascular endothelium disorder?
Rare
* Vasculitis; vascular fragility (due to hyperadrenocorticism)
What are the 4 types of thrombocytopenia?
Decreased production – bone marrow disease, ehrlichiosis, drug
reactions, oestrogen toxicity, myelofibrosis
* Increased consumption – bleeding, thrombosis, DIC
* Destruction – immune-mediated thrombocytopaenia (ITP)
* Splenic sequestration – torsion, neoplasia, sepsis
What may cause thrombopathia?
Hereditary or acquired
* vWF deficiency (vWD) – Some DOG breeds
* Glanzmann’s thrombasthaenia
* Chediak-Higashi syndrome – CAT
* NSAIDs, DIC, liver failure, uraemia
When does hypercoagulation occur?
Increased platelet or coagulation factor activity. * Deficient anticoagulation factors or decreased fibrinolysis. * Vascular stasis or vascular damage.
How would you treat vitamin K antagonism?
Subcutaneous injection q 12h until PCV is stable and active bleeding
decreased
* Followed by oral Vit K1 q 12h for 2 weeks
* Can taper every 2 weeks and continue for 6-8 weeks
* Monitor with PT and aPTT 48 hours after last dose
How would youi treat hypercoagulation?
Low dose aspirin or clopidogrel
How would you treat hyperfibrinolysis?
Tranexamic acid – decreases fibrinolysis and increases clot strength
How would you treat immunosuppression?
Prednisolone; azathioprine, cyclosporine, mycophenolate mofetil,
leflunomide
