Download a. According to the color & composition of thrombi

Hemodynamic Disorders
(Disorders of blood flow)
Dr. Abdelaty Shawky
Dr. Gehan Mohamed
* 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.
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.
b. According to the site of thrombus:
1. Venous thrombi (the most common):
2. Arterial thrombus: less common.
3. Cardiac thrombi: found in the heart chambers
and valves.
4. Capillary thrombi: rare.
Femoral vein thrombosis
Coronary artery thrombosis
Mural thrombus of left ventricle
c. According to presence or absence of
bacteria:
1. Septic thrombus: containing pyogenic
bacteria.
2. Aseptic thrombi: without bacteria.
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:
a. Thrombophlebitis: occurs in the sitting of inflammation.
b. Phlebothrombosis: occurs in the sitting of stasis.
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.
3. Cardiac thrombi:
- found in the heart chambers and valves.
- Include:
1. Auricular thrombus: in the left atrium over
auricular appendages in case of mitral valve
stenosis.
2. Mural thrombus in the left ventricle over an
area of myocardial infarction.
3. Vegetations: on the heart valves in rheumatic
fever, systemic lupus erythematosus, and
bacterial endocarditis.
4. Capillary thrombi: in cases of severe acute
inflammation and frost bites.
* 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.
Thrombus: organized & recanalized
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
* Differences between thrombus and clot:
Thrombus
Clot
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
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
EMBOLISM
* 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).
* 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.
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.
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.
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…….
* 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
Sudden death
healthy lung congested lung
No effect
infarction
lung fibrosis
Fat embolism
* Causes:
1. Fracture of long bones e.g. femur, humerus.
2. Extensive burns.
3. Trauma to severe fatty liver.
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.
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 .
Chronic Ischemia
* Causes: Gradual and incomplete arterial
occlusion by:
1. Atherosclerosis.
2. Pressure on the artery by enlarged lymph node,
tumor ... etc.
* 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.
References:
Robbins and Cotran’s: Pathologic Basis of
Disease. Seventh edition.