Hemodynamic%20Disorders%20(Disorders%20of%20blood%20flow)

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Hemodynamic Disorders(Disorders of blood flow)
Dr. Abdelaty Shawky Dr. Gehan Mohamed
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Classification of thrombi

• a. According to the color composition of
  thrombi.
• b. According to the site of thrombus.
• c. According to presence or absence of bacteria.
  

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• a. According to the color composition of
  thrombi
• 1. Pale thrombus formed of platelets and
  fibrin with few RBCs.
• 2. Red thrombus formed of platelets and
  fibrin with excess RBCs.
• 3. Mixed thrombus containing parts of pale
  thrombus and parts of red thrombus.

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• b. According to the site of thrombus
• Venous thrombi (the most common)
• 2. Arterial thrombus less common.
• 3. Cardiac thrombi found in the heart chambers
  and valves.
• 4. Capillary thrombi rare.

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Femoral vein thrombosis
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Coronary artery thrombosis
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Mural thrombus of left ventricle
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• c. According to presence or absence of bacteria
• 1. Septic thrombus containing pyogenic
  bacteria.
  2. Aseptic thrombi
  without bacteria.

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1. Venous thrombosis

• Thrombosis in veins is more common than other
  sites because of their slow blood flow, thin
  non-muscular wall and superficial in location.
• Thrombosis in veins may be either
• Thrombophlebitis occurs in the sitting of
  inflammation.
• b. Phlebothrombosis occurs in the sitting of
  stasis.

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2. Arterial thrombosis

• Less common than venous thrombosis because of the
  rapid blood flow and the thick elastic arterial
  wall which resists injury.
• Thrombosis occurs in arteries affected by
• atherosclerosis.
• Arteritis.
• aneurysms.
• Arterial thrombosis ? ischemia ? infarction.

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3. Cardiac thrombi

• found in the heart chambers and valves.
• Include
• Auricular thrombus in the left atrium over
  auricular appendages in case of mitral valve
  stenosis.
• Mural thrombus in the left ventricle over an
  area of myocardial infarction.
• Vegetations on the heart valves in rheumatic
  fever, systemic lupus erythematosus, and
  bacterial endocarditis.

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• 4. Capillary thrombi in cases of severe acute
  inflammation and frost bites.

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Fate and complications of thrombi

• It depends upon its size whether it is septic
  or aseptic.
• ? Septic thrombi
• Fragments by proteolytic enzymes into septic
  emboli ? pyaemic abscesses.
• ? Aseptic Thrombi may undergo
• - Small thrombi is dissolved and absorbed.
• - Large thrombus undergoes
• 1- Organization ,canalization .
• 2- Calcification.
• 3- Fragmentation and embolism.

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Thrombus organized recanalized
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Post mortem Blood Clot

• A mass of blood elements formed by transformation
  of fibrinogen to fibrin, in stagnant blood.
• The clot is dark red with a glistening smooth
  surface, and is not adherent to the vessel wall.
• Clotting of blood may be .
• 
  Inside the CVS
• 
  after death
• 
  (postmortem clots)
• 
  red yellow

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Differences between thrombus and clot
Clot Thrombus
1- Occurs in stagnant blood after death 2- Loosely attached 3- Soft and moist 4- Red or yellow 5. Formed of fibrin and blood elements. 6- No lines of Zhan 1- Occurs in circulating blood during life 2- Firmly attached 3- Friable and dry 4- Pale, red or mixed. Formed mainly of fibrin, platelets. 6- May show lines of Zhan
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EMBOLISM
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• Definition
• - Is the process of circulation of insoluble
  material in the blood and its sudden impaction in
  a narrow vessel.
• - This insoluble material is called (embolus).

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• Causes Types of embolism
• 1. Thrombo-embolism the embolus is detached
  thrombus)
• 2. Fat embolism the embolus is fat.
• 3. Air embolism the embolus is air bubbles.
• 4. Parasitic emboli the embolus is a parasite
  e.g. bilharzial worms and ova.

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• 5. Tumor emboli the embolus is groups of tumor
  cells penetrating the wall of blood vessels
  especially veins.
• 6. Amniotic fluid embolism the embolus is an
  amniotic fluid embolism during labor.

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1. Thromboembolism

• - According to the site of origin and the site of
  impaction, there are 3 types
• 1. Pulmonary embolism the embolus coming from
  the systemic veins and get impacted in pulmonary
  blood vessels.

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• 2. Portal embolism the embolus coming from
  gastrointestinal organs get impacted in the
  portal veins .
• 3. Systemic embolism the embolus coming from the
  left side of the heart or systemic artery and get
  impacted in systemic organ e.g. brain, kidney,
  spleen.

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Effects of thromboembolism

• Effects depends upon
• 1- Size of the embolus.
• 2- Nature of the embolus (septic or aseptic).
• 3- State of the collateral circulation in the
  affected site.
• Effects of pulmonary embolism
• Big embolus Medium sized embolus
  Recurrent Small emboli
• healthy lung
  congested lung
• Sudden death No effect
  infarction lung fibrosis

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Fat embolism

• Causes
• 1. Fracture of long bones e.g. femur, humerus.
  
• 2. Extensive burns.
• 3. Trauma to severe fatty liver.

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Ischemia

• Definition
• Deficient arterial blood supply to an organ or
  tissue due to partial or complete occlusion of
  its artery.
• Types
• 1. Acute ischemia
• - Sudden and complete occlusion.
• 2. Chronic ischemia
• - Gradual and partial occlusion.

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Acute ischemia

• Causes Sudden complete arterial occlusion by
• 1. Thrombosis or embolism. (most common)
• 2. Surgical ligature of the artery.
• Effects
• Organs with good collateral circulation? No
  effect.
• Organs with poor collateral circulation ?
  infarction .

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Chronic Ischemia

• Causes Gradual and incomplete arterial
  occlusion by
• 1. Atherosclerosis.
• 2. Pressure on the artery by enlarged lymph
  node, tumor ... etc.

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• Effects
• Organs with good collateral circulation ? No
  effect.
• Organs with poor collateral circulation ? chronic
  ischaemic changes
• Cellular degeneration, atrophy followed by
  fibrosis.
• Clinically manifested e.g. by angina pectoris,
  intermittent claudication.

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• References
• Robbins and Cotrans Pathologic Basis of
  Disease. Seventh edition.