Hemodynamics cumulative Flashcards
(97 cards)
Differentiate thrombus from clot (in general )
Clot:-Platelets not involved.
- Occurs outside vessel (test tube, hematoma) or inside (Postmortem)
- Red
- Gelatinous
- Not attached to the vessel wall
- No lines of Zah
Features of arterial thrombus (gross and histological)
- pale infarct
- Microscopy - lines of Zahn • Alternate pale and dark lines • Light – platelets and fibrin • Dark - RBCs
FAtes of thrombus
- progression
- formation of an embolus
- resolution/ dissolution
- organization and recanalization
Sites of thrombosis – arterial
Heart (mural) • Aorta (on atherosclerotic plaque) • Aneurysm (mural) • In other arteries (occlusive) • Coronaries • Carotids, cerebral • Femoral • Mesenteric
Formation of venous thrombosis
Takes the shape of vessels in which it forms • Redder than arterial thrombus • Superficial veins of legs (varicosities)- rarely embolize • Deep veins of legs (90%) • Deep calf veins- (at or above the knee) femoral, popliteal, iliac
clinical signs and symptoms of venous thrombosis
- • Asymptomatic in 50%- due to collaterals
- but deep veins have a large risk to embolise as compared to superficial veins (emobolism tends to go to pulmonary circulation)
• Trousseau’s Syndrome
unexplained thrombophlebitis (thrombus associated edema ) Underlying cause could be pancreatic tumor or any coagulatin acitivation tumor- release of procoagulant)
affect of an arterial thrombus
• Acute - Infarct • Slow - atrophy, fibrosis • Heart - systemic emboli
Effect of a venous thrombus
• Edema, congestion • Rarely- the pressure of edema leads to secondary block of the artery leading to infarction • Embolization to lungs
define embolism
Occlusion of a part of vascular tree by a mass (solid, liquid, gas) that is carried by the blood to a site distant from its point of origin to the site where it becomes impacted
what is the most common site of an embolism and what is most clinically significant emobolis
Statistically the commonest origin is from the deep leg veins and reaches the lungs but most of these are clinically silent -The commonest clinically significant thromboemboli arise from the heart (80%) Embolize to the lower extremities (75%), and brain (10%
Pulmonary Thromboembolism
The commonest origin is from the deep leg veins and reaches the lungs but most of these are clinically silent
- The commonest origin is from the deep leg veins and reaches the lungs but most of these are clinically silen
Pulmonary thromboembolism
• Massive • Sudden obstruction of 60% of pulmonary vasculature; sudden death, no time to develop infarction • Major • Multiple medium sized vessels occluded – dyspnea, pain • Infarction only in 10% because of collateral circulation by bronchial arteries • Minor • Small vessels obstructed, get lysed, remain asymptomatic
(Recurrent pulmonary emboli – pulmonary hypertension
MAJOR is the only time you see an infarction
most likely site of origin in pulmonary thromboembolis
- in the deep veins of legs
Most likely site of systemic thromboembolism
- mural thrombus
- paradoxycal thrombus (carried from the venous side to the arterial side -atherosclerotic plaque
effect of a thrmboemobolism
Effect : embolize to the lower extremities (75%) and brain (10%) • they block an end artery leading to infarction
etiology Fat embolus
Trauma to bone, subcutaneous tissue, burns • Fat globules enter the circulation by rupture of the marrow vascular sinusoids or rupture of venules
pathogensis of fat embolism
• Mechanical blockage - Globules enlarge in circulation, platelets adhere • Biochemical injury – Free fatty acids are released from adipose tissue in the circulation and are toxic to endothelial cells – DIC, clogged pulmonary and systemic capillaries
Clinical features of Fat embolism
fat embolism syndrome (fat embolism syndrome characterized by pulmonary insufficiency, neurologic symptoms, anemia, thrombocytopenia, and a diffuse petechial rash )
- s appear 1 to 3 days after injury as the sudden onset of tachypnea, dyspnea, tachycardia, irritability, and restlessness, which can progress rapidly to delirium or coma
fat embolism syndrome features
fat embolism syndrome characterized by pulmonary insufficiency, neurologic symptoms, anemia, thrombocytopenia, and a diffuse petechial rash
lab investigations of FAt embolism
Sudan 4 black stains. osmium acid and oil red
- fat glbules in sputum and urine,
- No tested treatment, just keep them hemodynamically stable and maintain oxygenation
Fatal in about 10% of cases
Prognosis of fat embolism
No tested treatment, just keep them hemodynamically stable and maintain oxygenation
Fatal in about 10% of cases
FAt embolism staining technique requirements
frozen section of tissues since routine processing through alcohol will dissolve the fat
Air embolism etiopathogensis
• Air may be introduced into the venous circulation through neck wounds, thoracocentesis, Cut in internal jugular vein, and hemodialysis • Child birth, abortion • 150 ml of air causes death • Air bubbles tend to coalesce and physically obstruct the flow of blood in the right ventricle, lungs, and the brain