Pathology of circulatory disorders Flashcards
(28 cards)
What are the terms used to describe an increase in blood volume within organs and tissues caused by dilation of blood vessels?
- Hyperaemia: active process; increase arterial flow
- Congestion: passive process; decrease venous outflow
What is oedema?
- an increase in interstitial fluid in tissues
- occurs when hydrostatic pressure is higher that the plasma colloid osmotic pressure (PCOP)
Generalized oedema?
anarsarca (swelling throughout the body; can occur in various parts of the body including the skin, subcutaneous tissue, and internal organs)
Localized oedema?
- hydrothorax (buildup in pleural cavities)
- hydropericardium (build up in pericardial cavity)
- ascites (abnormal buildup of fluid in the abdominal cavity)
what are some egs of small bleeds?
- petechiae: 1-2 mm
- purpura: 3-5 mm
- ecchymoses (bruise): 1-2 cm
What are the classes of large bleeds?
- Class I Haemorrhage: up to 15% loss of circulating blood volume
- Class II Haemorrhage: 15-30%
- Class III Haemorrhage: 30-40%
- Class IV Haemorrhage: >40%
whats menorrhagia?
menstrual bleeding longer than 7 days
Thrombus location, appearance and mechanism?
- intravascular
- granular, firm but friable (macro); lines of zahn (micro)
- vascular injury, platelets involved
Clot location, appearance and mechanism?
- extravascular (except at postmortem-chicken fat appearance)
- shiny, smooth, moist
- stasis, extravasation, no platelets involved
Predisposing factors to thrombosis?
- vessel wall
- blood flow
- constituents of blood
note: think of virchow’s triad
Give some causes of hypercoagulability. hint: 9
- pregnancy postpartum
- major surgery
- malignancy
- infection/sepsis
- autoimmune disease
- oestrogen therapy
- inflammation
- dehydration
- inherited thrombophilia (form clots easily)
Give some causes of vascular damage. hint: 3
- physical trauma, strain or injury
- microtrauma to vessel wall
- atherosclerosis
Give some causes of circulatory stasis. hint: 4
- immobility
- venous obstruction
- congenital abnormalities affecting venous anatomy (may-thurner and paget-schroetter syndrome)
- low heart rate and low BP
What are the components of Virchow’s triad?
- endothelial injury
- abnormal blood flow
- hypercoagulability
What causes arterial thrombosis?
- high flow issues
- mainly due to vessel wall damage: atherosclerosis, neoplasia, inflammation (arthritis, trauma)
- constituents: neoplasia, thrombophilia (thrombocytosis),
- flow: negligible except in aneurysms
What causes venous thrombosis?
- slow blood issues
- mainly due to blood flow problems: systemic- congestive cardiac failure, shock; local- mass effect/ immobility
- constituents: thrombophilia
- vessel wall: direct trauma, pressure
What causes thrombus in the heart?
- mainly due to blood flow and vessel wall factors
- atria: mitral stenosis, mitral regurgitation- abnormal blood flow
- ventricle: myocardial infarction- vessel wall changes; congestive cardiac failure- abnormal blood flow
- valves- infective endocarditis, rheumatic heart disease- abnormal blood flow
What is the fate of the thrombus?
- attached: lysis/resolve, organize/recanalize, propagate
- detached: embolize
What are the complications of thrombosis?
- can obstruct blood vessel and lead to infarction (ischaemic injury)
- it can dislodge/fragment and become and embolus
Whats an embolus?
- an abnormal undissolved mass that is transported from one part of the circulation to another remote from its site of origin (enters blood stream)
- inevitably lodge in the vessels (occlusion)
what are the types of emboli?
- solid: thrombus, atherosclerotic plaque, fat droplets, tumour tissue, bone marrow fragments, shrapnel
- liquid: amniotic fluid
- gas: nitrogen gas, air
whats the most common form of thromboembolism?
pulmonary embolism
How do pulmonary emboli arise?
95% from deep leg veins proximal to popliteal fossa
what are the different sizes of emboli and what can they cause?
- large emboli can lead to death
- medium sized emboli can lead to mild SOB
- small emboli can lead to infarction and haemoptysis/asymptomatic
note: repeated small emboli can lead to pulmonary hypertension
