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