Haemodynamic Disorders Flashcards
Describe oedema
Excess watery fluid collecting in cavities or tissues of the body
Describe the mechanism of oedema formation
Increased microvascular permeability
Increased intravascular hydrostatic pressure
Reduced intravascular osmotic pressure
Reduced lymphatic drainage
Describe the consequences of oedema depending its location
Subcutaneous - reduced wound healing/infection clearance
Pulmonary - Reduced oxygen diffusion
Brain - Life threatening
Define haemostasis
= arrest of bleeding (physiological response to vascular damage)
Describe the three stage process of haemostasis
- (primary haemostasis) Formation of platelet plug. Arteriolar vasoconstriction, Platelet adherence and activation (may be sole action in minor damage)
- (secondary haemostasis) Formation of fibrin meshwork - local activation of coagulation cascade= fibrin polymerisation (by thrombin) Fibrin cements platelets into a secondary haemostatic plug
- Removal of platelet /fibrin plug - Thrombolysis occurs once the vessel has healed
Describe disseminated intravascular coagulation
= Severe dyshaemostatis caused by excess production of thrombin
What can be the causes of DIC?
Diffuse vascular disease
Systemic infections
Other stimuli that activate release of inflammatory mediators
Describe the mechanism of DIC
Disseminated intravasculae coagulation
- Excess thrombin
- Platelet aggregation and conversion of fibrinogen to fibrin
- widespread microvascular clots
- Consumption of coagulation factors
- Widespread hemorrhage
Give 3 causes of haemorrhage
Abnormal function /integrity of:
- endothelium of blood vessels
- platelets
- coagulation factors
Define petchia
Pinpoint haemorrhage
Define Eccymosis
Haemorrhage to 2-3 cm
Define haematoma
Focal, confined harmorrhage
Define thrombosis
formation of inappropriate clots
Give the three causes of thrombosis
(Virchow Triad)
Endothelial injury
Alteration of Blood flow
Hypercuagulability
What determines the effects of thrombosis
Location and ability to disrupt tissue activity
