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Pathology Course 302

Pathology Course 302. بسم الله الرحمن الرحيم. COURSE POLICY. Students are expected to be on time . Student are expected to close his mobile. Students are expected to avoid side talk with colleagues. Prof.Dr Sherein Saied Abdelgayed. Academic Positions

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Pathology Course 302

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  1. Pathology Course 302

  2. بسم الله الرحمن الرحيم

  3. COURSE POLICY Students are expected to be on time. Student are expected to close his mobile. Students are expected to avoid side talk with colleagues.

  4. Prof.DrSherein Saied Abdelgayed Academic Positions Full Professor, Pathology Department, Faculty of Veterinary Medicine, Cairo University, 2014 Professor Assistant, Pathology Department, Faculty of Veterinary Medicine, Cairo University, 2009 Lecturer, Pathology Department, Faculty of Veterinary Medicine, Cairo University, 2004 Assistant Lecturer, Pathology Department, Faculty of Veterinary Medicine, Cairo University, 1999 Demonstrator, Pathology Department, Faculty of Veterinary Medicine, Cairo University, 1995

  5. Prof.DrSherein Saied Abdelgayed Professional Qualifications Conferences: 20 (Local and international) Training courses: 40 (Attendant and Lecturer) Professional Memberships : 42 a) Editorial and Reviewing Committees b) Scientific Committees c) Scientific Associations and societies d) Technical Committees Publications : 52 a) 22 International b) 24 Local c) 6 Conference

  6. HEMODYNAMIC DISTURBANCES(Disorders of blood flow)

  7. CIRCULATORY DISTURBANCES 1- Hyperemia 2- Congestion 3-Thrombosis 4- Embolism 5- Ischemia 6- Infarction 7-Hemorrhage 8- Edema 9- Shock

  8. Learning objectives • Identify definition,types,causes and effect of both hyperemia & congestion. • Understand definition,causes,composition,types,sites and fate of thrombosis. • Discuss definition,causes,composition,types,sites and fate of emboli. • Understand definition,causes,typesand effect of ischemia. • Discuss definition,causes,types, and fate of infarction. • identify definition,causes types, and fate of hemorrhage. • Understand definition,causes,types of edema. • Discuss definition and types of shock.

  9. II- Thrombosis 1- Definition 2- Causes 3- Composition 4- Types 5- Sites 6- Fate

  10. Definition of thrombosis • Thrombosis is: -The formation of a solid mass (compact mass) - Composed of the blood elements. - In a blood vessel or heart. - In circulating blood. - During life.

  11. Causes of thrombosis There are 3 major factors which predispose to thrombosis (Virchow’s triad) 1- Endothelial damage 2- Slowing & turbulence of blood flow 3- Changes in blood composition

  12. Virchow triad in thrombosis

  13. Causes of thrombosis 1- Endothelial damage: - Endothelial damage may be: Mechanical, inflammatory, or degenerative. The injured endothelium becomes swollen with rough surface. 2- Staisis: There is slowing of blood flow * In the heart as in mitral stenosis * In blood vessels as in varicose veins and Anurysm.

  14. 3- Changes in composition of blood: • ↑ platelets e.g. after operations. • ↑ fibrinogen as in pregnancy. • ↑ R.B.Cs. (polycythemia) → ↑ viscosity of blood → stasis → thrombosis. • ↑ W.B.C. as in leukemia → ↑ viscosity of blood → stasis → thrombosis.

  15. Pathogenesis (Mechanism) of thrombosis: • Plateletsleave the blood stream, agglutinate and adhere to the damaged endothelium. • They form laminae, which are arranged vertical to the blood stream and called lines of Zhan. - Soon, fibrin accumulates around them with red and white blood cells.

  16. Lines of Zhan

  17. Morphology • Arterial thrombi • Originate from injury sites • Venous thrombi (Phlebothrombi) • Originate from the sites of stasis both extends to the heart pale platelet and fibrin layers Lines of Zahn dark erythrocyte-rich layers

  18. thrombosis Lines of Zahn

  19. thrombosis LM: Platelets Trabeculae + Neutrophil+ fibrin + red cells

  20. Classification of thrombi • According to the color & composition of thrombi • According to the site of thrombus: • According to presence or absence of bacteria:

  21. According to the color & composition of thrombi: 1- Pale thrombus: formed only of platelets and fibrin. 2- Red thrombus: formed mainly of red cells and fibrin. 3- Mixed thrombus: containing all blood elements.

  22. According to the site of thrombus: 1-Venous thrombus (the most common): formed in veins as in varicose veins and after major abdominal operations. 2-Arterial thrombus: found in atherosclerosis and aneurysm. (Latteral & Occlusive) 3-Cardiac thrombus: found in the heart, either in the heart chambers called mural thrombus or on the heart valves called vegetations. 4-Capillary thrombi 5- Lymphatic thrombi

  23. MURAL THROMBI, HEART

  24. According to presence or absence of bacteria: 1- Septic thrombus: Containing pyogenic bacteria. 2- Aseptic thrombi: without bacteria.

  25. thrombosis Mural thrombus Vegetation

  26. Gross picture of the thrombus

  27. Left atrial Thrombus

  28. Microscopic picture of thrombus:

  29. 1- Venous thrombosis Thrombosis in veins is more common than other sites because of their slow blood, and thin wall. Thrombosis in veins may be either: • Thrombophlebitis • Phlebothrombosis Venous thrombosis → Stasis → Thrombosis

  30. 2- Arterial thrombosis ● Less common than venous thrombosis because of * Rapid blood flow in the arteries * Thick elastic arterial wall which resists injury. ● Thrombosis occurs in arteries affected by: Atherosclerosis, arteritis, & aneurysms (due to stasis, disordered blood flow & roughness of the intima). ● Arterial thrombosis → ischemia → Necrosis & Infarction.

  31. thrombosis Clinical correlations • Venous thrombosis (phlebothrombosis) • Varicosities, embolism (sometimes fatal), • DVT, trauma, surgery, post partum • Cancer associated thrombosis • Cardiac and arterial thrombosis • Mural thrombus and vegetation theombus • cardiac infarction, rheumatic heart disease • Embolize peripherally, brain, kidney, spleen, etc

  32. Disseminated Intravascular Coagulation (DIC) • basis: widespread activation of thrombin • Mi: fibrin thrombi in microcirculation • 1. stage • multiple fibrin thrombi in microcirculation  consumption of PLT + coagulation proteins • 2. stage • fibrinolytic system activation  serious bleeding

  33. DIC - causes • 1. obstetric complications • abruptio placentae  retroplacental hematoma • amniotic fluid embolism • septic abortion • 2. infections • sepsis (Gram +, Gram- bacteria) • meningococcemia • 3. neoplasms • carcinomas of pancreas, prostate, lung, leukemias • 4. tissue injury • burns

  34. Fate of thrombi It depends upon its size & whether it is septic or aseptic. ● Septic thrombi: Fragments by proteolytic enzymes into septic emboli →payaemic abscesses. ● Aseptic Thrombi:may undergo: - Small thrombi is dissolved and absorbed. - Large thrombus undergoes: 1- Organization ,canalization . 2-Calcification. 3- Fragmentation and embolism.

  35. Thrombus: organized & recanalized

  36. Significance 1- Thrombi play beneficial role in controlling hemorrhage. 2- Harmful effects of thrombi depend upon the location, (organ) and size of blood vessel involved. In organs with abundant collateral circulation, thrombi have negligible effect. But in case of end arteries there maybe necrosis and infarction. 3- The most harmful effect of thrombi is embolism. 4- Other harmful effects include edema, atrophy and aneurysm etc.

  37. 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: → Outside the CVS Inside the CVS: During lifeafter death (e.g. in stagnant blood) (Postmortem clots) red yellow

  38. Difference between thrombus and clot:

  39. Thrombus It is granular, dry and rough White or pale in colour Attached to the vessel wall. Stratified in structure Composed mainly of platelets Postmortem clot It is rubbery, gelatinous and moist. Intense red or yellow in colour Not attached to the vessel wall. Uniform in structure. Composed mainly of fibrin. Comparison of thrombus and postmortem clot

  40. Thrombus Vascular endothelium is damaged/rough It is formed in a flowing blood stream It is formed in a living animal Maybe partially organized Caused by endothelial injury Postmortem clot Vascular endothelium is undamaged and smooth Forms in stagnant blood Formed in a dead animal No indication of organization Initiated by thromboplastin tissue factor Comparison of thrombus and postmortem clot

  41. III- EMBOLISM • DEFINITION • CAUSES & TYPES • Result

  42. Embolism ● Definition Embolus:An insoluble (solid, liquid or gaseous) mass circulating in the blood stream. Embolism:Is the process of impaction of the embolus in a narrow vessel.

  43. Embolism ● Causes & Types: 1- Detached thrombi (thrombo-embolism) 2- Fat embolism: The fat of the bone marrow reaches the circulation after fracture of bones. 3- Air embolism: due to injury of neck & chest veins. 4- Parasitic emboli: e.g. bilharzial worms and ova. 5- Tumor emboli: groups of tumour cells penetrate the wall of blood vessels especially veins. 6- Amniotic fluid embolism during labour.

  44. 1- Detached thrombi (Thromboembolism) • Sites of impaction: 1- Pulmonary embolism :the embolus get impacted in pulmonary blood vesseles. 2- Portal embolism : the embolus coming from gastrointestinal organs get impacted in the portal veins . 3- Systemic embolism : here the embolus get impacted in any blood vessel in systemic circulation.

  45. 1- Detached thrombi (Thromboembolism) 4- Paradoxical embolism i.e.the embolus coming with venous return to be impacted in lung causing pulmonary embolism but instead of that it will pass from right side of heart to its left side through septal defect then pass to systemic circulation.

  46. Effects of thromboemboli • 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 embolusMedium sized embolusSmall embolus

  47. Effects of thromboemboli • 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 embolusMedium sized embolusSmall embolus Acute Rt sided Heart failure Sudden death

  48. Effects of thromboemboli • 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 embolusMedium sized embolusSmall embolus Acute Rt sided healthy lung Heart failure no effect Sudden death

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