Thrombosis, Embolism and Shock Flashcards
What is a thrombosis?
formation of a solid or semi-solid mass from the constitutes of the blood.
What are examples of where thrombi may form?
- lumen of the heart
- arteries
- veins
- capillaries
When might a thrombi form in the lumen of the heart?
after MI
What is disseminated intravascular coagulation?
- formation of a clot in small blood vessels
- involves both thrombus formation and haemorrhage
- minute thrombi may cause scattered ischaemic lesions
What are the triggers for disseminated intravascular coagulation?
- infection
- septicaemia
- malaria
- neoplasm
- liver disease
What are factors that promote thrombosis? (Virchow’s triad)
- abnormalities of vessel wall
- abnormalities of blood flow
- abnormalities of the bloods constituents
What is atherosclerosis?
a disease were plaque builds up inside your arteries
What can cause abnormalities in the artery walls?
inflammation
heart attack
rheumatic endocarditis
What can cause abnormalities in the vein and capillary walls?
trauma inflammation chemical such as :- - sclerosants (irritant substances injected to obliterate varicose veins) - glucose (artheroma in diabetes )
What can cause abnormalities in blood flow in arteries?
turbulence aneurysms (bludge in blood vessel caused by weakness in wall) plaques spasms atrial fibrillation
What can cause abnormalities in blood flow in veins?
compression
inactivity
heart failure
circulatory shock
What can cause abnormalities of the blood constituents?
- increased viscosity
- hyperproteinaemia
- multiple myeloma (tumour in bone marrow)
- abnormalities of clotting
What may cause abnormalities of clotting?
- pregnancy
- contraceptive pill
- following trauma liver may produce more clotting factors
- tumours
- thrombocythaemia (blood disorder, over production of platelets )
- inherited
What may cause increased viscosity?
- polycythaemia (increased haemoglobin)
- dehydration
- chronic hypoxia
- polycythaemia rubra vera (bone marrow makes to many red blood cells )
If a thrombi detaches it becomes a …
thromboembolism
What is an embolism ?
transport of abnormal material (solid, liquid, gas) by the blood stream and its impacting in a blood vessel
Fat emboli is normal caused by what?
physical trauma such as fracture of a long bone, soft tissue trauma or a burn
When might a gas emboli occur?
infusion
vascular surgery
caisson disease
What is caisson disease ?
happens when ascending from depth too rapidly
bubbles of nitrate form in blood stream
on enter bones and joints cause pain known as the bends
When might a emboli involving tumour material occur?
when tumour penetrates blood vessel
parts may break away to form metastases
Give an example of infective agent emboli.
fragments of vegetation growing on heart valves in infective endocarditis
atheroma
fragments of artheromatous plaque may break off
Explain how amniotic fluid may become an emboli
uterus may force amniotic fluid and squames from infant into uterine veins of mother.
When may foreign bodies cause emboli ?
iv drug abuse
iatrogenic (caused by medical examination or treatment)
What is shock ?
- physiological state characterised by
- reduction in tissue perfusion
- resulting in decreased tissue oxygen delivery
- insufficient removal of cellular metabolic products
- resulting in tissue injury
What are the clinical features of shock ?
- low BP
- tachycardia
- abnormal respiratory rate
- low urine output
- metabolic acidosis
- hypoxia
- cutaneous vasoconstriction or vasodilation
- anxiety, agitation, indifference, lethargy, obtunded ( not alert )
A clinical sign of shock is low BP.. what in particular are you looking for?
systolic under 110
A clinical sign of shock is tachycardia.. above how many beats a minute is this..
90
A clinical sign to watch in shock is urine output…. What would we be looking for?
low urine output
A clinical sign of shock is metabolic acidosis, what is this?
- excessive amount of acid produced when kidneys are not removing enough from the body
A clinical sign of shock is cutaneous vasoconstriction or vasodilation what is cutaneous?
affecting the skin
Why may hypovolaemic shock occur?
- haemorrhage (internal or external )
- severe nurns
When might cardiogenic shock happen?
- large acute myocardial infarction
- other acute cardiac disease
When might septic shock occur?
- from endotoxins from gram negative bacteria
- exotoxins from gram positive bacteria
- both these leads to dilation of blood vessels
When might anaphylactic shock occur?
- severe form of allergic reaction (food, antibiotics, insect sting)
When might neurogenic shock occur?
- spinal cord trauma
- regional anaesthesia
When might obstructive shock occur?
- cardiac tamponade (compression of heart by an accumulation of fluid in pericardial sac)
- tension pneumothorax (build up of air in pleural space)
- massive pulmonary embolism (blockage in pulmonary arteries)
