Post on 17-Jul-2015
Virchow’s Triad:::
Endothelial Injury
Stasis or Blood
turbulence
Hypercoagulability
Virchow’s Triad:::
Endothelial Injury
Stasis or Blood
turbulence
Hypercoagulability
Loss of endothelium exposes Subendothelial collagen
Etiology: HypertensionEndotoxinsScarred valvesHyperhomocystinemia HypercholesterolemiaSmokingRadiation
1. ENDOTHELIAL INJURY
Turbulence Arterial thrombus Stasis Venous thrombus
Alteration in Flow causes…. Disrupt the laminar blood flow Cause concentration of Clotting factors Permit build of thrombi Promote endothelial cell activation
2. ALTERATIONS IN BLOOD FLOW
PRIMARY/ GENETIC: Factor V Leiden mutation Prothrombin mutation Antithrombin III deficiency Protein C & Protein S deficiency
ACQUIRED CAUSES: Prolonged bed rest- Immobilization Myocardial Infarction Surgery, Fracture, Burns Cancer, Cardiac valves, DIC, SLE Hyperestrogen states, Smoking, Sickle cell anemia,
Nephrotic syndrome.
3. HYPERCOAGULABILITY
Qn
Previous extensive transmural myocardial infarction.
The stasis of blood in the aneurysm predisposes to mural thrombosis.
Deep thrombi occur in large veins of leg
DVT are asymptomatic in 50 % of patients
Trousseau Syndrome: Tumor associated
procoagulant release Increased risk of
Thromboembolic phenomenon in disseminated
cancers.
Also known as migratory thrombophlebitis
Ca Pancreas, Prostate, Stomach, Breast, Lung,
Osteosarcoma, AML- M3.
Propagation
Embolization
Dissolution
Recanalization
Organization
FATE OF THROMBUS: PEDRO
Organized thrombus
“Detached Intravascular Solid, Liquid or
gas mass carried by blood to a distant
site.”
99% are Thrombo-embolus
Consequences of embolus is ischemic necrosis of
affected tissue.
EMBOLISM
Venous Embolism/ Pulmonary (DVT)
Arterial Embolism (Post MI)
Paradoxical Embolism (Venous will
become arterial: due to ASD/ VSD)
Fat embolism
Amniotic fluid embolism
Air embolism
Septic embolism
Foreign body embolism.
Types of Embolism:
Most commonly from venous emboli from leg
veins (DVT)
“Saddle embolus” obstructs main Pulmonary
artery
Once a Pulmonary embolus occurs, patient
will be prone for recurrent emboli episodes.
Multiple emboli or shower of small emboli in
small pulmonary arteries.
PULMONARY EMBOLISM
Most arise from Intra cardiac mural thrombi
Left ventricular wall infarction and Mitral
stenosis predisposes to thrombi and embolus
Arterial emboli travel to wide variety of sites
Lower limbs, Brain, intestines, kidney,
spleen…….any organ.
SYSTEMIC THROMBOEMBOLISM
Microscopic fat globules enter circulation following
fracture of long bones
Fat embolism syndrome:: Symptoms appear 1- 3
days after injury
Pulmonary insufficiency: Tachypnea, Dyspnea, Tachycardia
Neurologic symptoms: Irritability, Restlessness, Delirium,
Coma
Low platelets: Petechial skin rash
Fatal in 10% of individuals
FAT EMBOLISM
Fracture long bones: Imp. Soft tissue trauma Burns Parenteral lipid infusion Sickle cell crisis Acute pancreatitis Liposuction Decompression sickness
CAUSES OF FAT EMBOLISM:
Gas bubbles in circulation
100 ml of air is needed to produce clinical
effect
Chest wall injury, Neck injury, Therapeutic, Intra-
operative
Decompression sickness seen in Deep sea divers
AIR EMBOLISM
Amniotic fluid into ruptured uterine veins
Grave, but uncommon complication
Important obstetric complication
Sudden onset of severe dyspnea, Cyanosis,
Hypotension, Shock, Seizures, Coma.
If survives… Pulmonary edema, DIC
AMNIOTIC FLUID EMBOLISM
An infarct is an area of ischemic necrosis caused
by occlusion of arterial supply or venous
drainage
Can be due to Thrombus, embolus, vasospasm,
atheroma, compression of vessels, etc.,
Venous blockade Congestion
INFARCTION
Classified based on the color1. Red (Hemorrhagic) infarct2. White (Anemic) infarct
Red infarcts are seen in::- Dual blood supply.. Lung, Small intestine- Loose tissues.. Lung- With venous occlusions (ovarian torsion) - Previously congested tissue
INFARCT MORPHOLOGY
White Infarcts::- Arterial occlusions- Organs with end arterial blood supply - Solid organs.. Heart, Spleen, Kidneys, Brain
Microscopy::- Coagulative necrosis- Liquefactive necrosis