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32 Cards in this Set

  • Front
  • Back

Embolism

It is a detached intravascular solid, liquid or gaseous mass that is transported in the blood from the site of origin to another site.

Solid emboli

oboemboli


Atheromatous material


Tumour emboli


ThromoboemboliAtheromatous materialTumour emboliTissue fragmentsBacterial clumpsParasitesForeign bodies


Tissue fragments


Bacterial clumps


Parasites


Foreign bodies

Liquid emboli

Fat


Bone marrow


Amniotic fluid

Gaseous emboli

Air


Other gases

Classify based on infected or not

Bland/sterile and septic

Classify based on the source

Endogenous and exogenous

Cardiac emboli

Arise from the left side of the heart.


From, atrial appendage,


left ventricle in MI,


vegetations on the valves in infective endocarditis

Vascular emboli

Arterial emboli - Atheromatous plaque, aneurysm


Venous emboli - DVT, tumour emboli


Lymphatic emboli - tumour emboli

Classify based on the flow of emboli

Paradoxically and retrograde emboli

Paradoxical emboli

Emboli originates in the venous circulation and bypass the lungs by travelling through a right-to-left shunt like ASD or interventricular defect. They enter the left side of the heart and block the blood flow to systemic arteries

Retrograde emboli

They travel against the flow of blood.


Ex. Prostatic carcinoma metastasis to the spine. It occurs through retrograde spread via the intraspinal veins which carry the emboli from large thoracic ducts and abdominal veins due to increased pressure in the body cavities.

Pulmonary embolism

An embolism in which the emboli occludes pulmonary arterial tree.

Site of origin of emboli

Deep leg veins - popliteal, femoral, iliac


Pelvic veins


Vena cava

Risk factor

Surgery


Advancing age


Obesity


Prolonged operative procedure


Postoperative infection


Cancer


Pre-existing venous disease

Mechanism

DVT undergoes fragmentation


!


The thromboemboli are carried through larger vascular channels


!


Right side of the heart


!


Right ventricle


!


Enter pulmonary arterial vasculature

Fate of pulmonary embolism

Resolution or organisation


Massive pulmonary embolism


Multiple recurrent pulmonary emboli


Paradoxical emboli

Saddle embolism

A large pulmonary embolus lodging at the bifurcation of main pulmonary artery. Produces acute massive obstruction to the blood flow to both lungs.



Effects;


Acute right ventricular failure


Shock:


Right ventricular failure


!


Reduction in left ventricular cardiac output


!


Sudden severe hypotension


!


May result in sudden death

Consequences

Pulmonary infarction


Pulmonary haemorrhage


Pulmonary hypertension


Minimal effect

Pulmonary infarction

An embolus can produce infarction in the patients with CCF or chronic lung disease.



Type - hemorrhagic type - blood supply to infarcted area by bronchial artery


Shape - pyramidal


Fate - granulation tissue grows from the edges of the infarct and results in organisation of infarct and forms a fibrous scar.



Clinical features


Cough


Stabbing pleuritic pain


Shortness of breath


Hemoptysis


Pleural effusion with the pleural fluid being blood stained.

Pulmonary hypertension

Multiple recurrent pulmonary emboli


!


Mechanical blockage of arterial bed


!


Pulmonary hypertension


!


Right ventricular failure.

Systemic thromboembolism

The emboli which occlude systemic arterial circulation


Produce infarcts in the region supplied by the involved vessel.

Sources

Heart:


Intracardiac mural thrombi - MI of left ventricular wall, mitral stenosis, dilatation of left atrium, atrium fibrillation.


Paradoxical emboli


Valvular source - bacterial endocarditis and prosthetic valves.



Blood vessels - on ulcerated atherosclerotic plaques or from aortic aneurysms



Unknown origin

Consequences

Arterial emboli travel, venous emboli lodge in a vascular bed - lung.


Arterial emboli pass through narrow arterial lumen and lodge at points where the lumen narrows abruptly - bifurcation or in the area of an atherosclerotic plaque.


Fate


Propagation and obstruction


Fragmentation and lysis

Major sites affected by arterial thromoboemboli

Lower extremity - gangrene


Brain - ischemic necrosis


Intestine - emboli in mesenteric vessels - infarction of the bowel


Kidney - renal artery embolism - peripheral infarcts


Blood vessels - emboli originating from bacterial vegetation - inflammation of arteries and mycotic aneurysm


Other sites - sleep and upper extremities

Fat and marrow embolism

Consists of microscopic globules of fat with or without bone marrow.

Causes

Trauma to adipose tissue with fracture


Soft tissue trauma and burns


Vigorous cardiopulmonary resuscitation

Manifestations

Usually asymptomatic


Fat embolism syndrome

Consequences

Sites of arrest of fat emboli -


Venous - lodged in the lungs.


Systemic circulation - arrested in brain, kidney, etc.,



Autopsy findings


Lung - acute respiratory distress syndrome.


Brain - cerebral edema, small hemorrhages and microinfarcts.

Clinical presentation

Time - 1 to 3 days after trauma


Respiratory symptoms - sudden onset of tachypnea, dyspnoea, tachycardia - lead to respiratory failure.


Neurologic symptoms - Irritability, restlessness, delirium, coma


Rapid onset of thrombocytopenia with diffuse petechial rash - diagnostic feature


Anemia


Chest radiography shows diffuse opacity of lungs - progress to opacification if lungs - characteristic of acute respiratory distress syndrome.

Air embolism - causes

Trauma - neck wounds and chest wall injury.


Surgical procedures - thoracocentesis, punctures of the great veins during obstetric or laparoscopic surgery, in coronary artery during bypass surgery, hemodialysis.


Amount of air required

More than 100cc

Mechanism

In circulation, air bubbles coalesce to form frothy masses that obstruct blood flow in the right side of the heart