lecture 14- vascular disorders 2 Flashcards
failure of haemostasis can result in what?
failure of haemostasis can result in -Haemorrhage Purpura; bleeding under skin petechia (purple spot caused by bleeding into the skin) haematoma; haemorrhage in a confined space haemorrhage into body cavities haemopericardium (blood in pericardium) -Thrombocytopenia deficient no. of platelets prolonged bleeding following trauma
List the causes of haemorrhages
causes of Haemorrhage
- disruption of normal haemostasis
- blood vessels/ endothelial image (trauma)
- Thrombocytopenia (defective platelet function)
- Coagulation factor deficiency (inherited or acquired disorders)
List the causes of thrombocytopenia
causes of thrombocytopenia
-failure of production (not producing any or enough)
radiation, drug toxicity, vaccination etc.
-increases destruction
primary immune mediated or secondary immune-mediated or alloimmune
-increased consumption (using up all your platelets) diffuse endothelial damage and platelet activation
Explain some disorders of platelet
disorders of platelet prolonged bleeding normal platelet count inability of platelets to adhere/ aggregate inherited (von Willebrand disease) acquired (uraemia)
Explain coagulopathy
Coagulopathy
bleeding disorder due to deficiency of 1 or more coagulation factors
acquired or inherited disorder
excessive bleeding
Discuss Disseminated intravascular coagulation
Disseminated intravascular coagulation (DIC)
secondary to severe disease
widespread consumption of platelets and coagulation factors
For the evaluation of haemostasis explain the following
complete blood count
platelet count
platelet function tests
-Complete blood count; WCC (white cell count)
-platelet count (compare to normal levels)
-platelet function test
buccal (cheek) mucosal bleeding time
aggregometry (how well platelets clump together to form blood clots)
For testing of plasma coagulation factors
- PT
- aPTT
- ACT
- TT
Test of plasma coagulation factors;
-prothrombin time (PT)
measure extrinsic and common pathway, detects deficiency of factor VII
-Activated partial thromboplastin time (aPTT)
measures intrinsic and common pathway, detects deficiency of factor VIII, IX, XI
-Activated clotting time (ACT)
less sensitive version of aPTT
-Thrombin time (TT)
measures deficiency of fibrinogen or stopping thrombin
Discuss Arterial thrombosis
Arterial thrombosis
endothelial damage important for arterial thrombus formation
causes by trauma toxins etc.
Discuss venous thrombosis
Venous thrombosis reduced/slowed blood flow aneurysms horses; intestinal torsion usually contain more erythrocytes than arterial thrombi