Fluid and Hemodynamic Alterations II Flashcards
What is a thrombus?
Ante-mortem blood clot formation on vascular wall within the CV system
What are thrombi made of?
Platelets, Fibrin, and Entrapped Cellular elements
What circumstances do you see clots in?
Extravascular (hematoma) and intravascular (postmortem space)
What are the components of a postmortem clot?
Coagulation factors and erythrocytes only
Gross appearance of a postmortem clot?
Currant-jelly clot
Chicken Fat Clot
Describe a currant jelly clot
Dark to red-black, smooth and shiney, rubbery, uniform, molded to the shape of the vessel, not attached, increased RBC levels
Describe a chicken fat clot
Like currant jelly, but yellow
Result of settling and separation of RBC and plasma
Gross appearance of thrombus
Heterogenous
More organized than clots, attached to wall
Laminated
Appearance of an arterial thrombi?
Pale. grey-tan, dry, friable, concentric layers, attached to vessel wall
Appearance of venous thrombi?
Red, friable, attached to vessel wall, confused with clot, often occlusive
Contents of a thrombus?
Fibrin, Platelets, WBCs, RBCs, +/- bacteria
What are the laminated lines of Zahn?
arterial thrombi, alternating layers of platelets/fibrin (pale) and RBCs (dark)
Thrombus vs. PM Clot. Formation?
T – Ante-mortem
C – Post-mortem
Thrombus vs. PM Clot. Cause
T – Endothelial Injury
C – Stagnant blood of dead animal
Thrombus vs. PM Clot. Attachment
T – Vessel Wall
C – None
Thrombus vs. PM Clot. Consistency.
T – Dry
C – Moist
Thrombus vs. PM Clot. Surface
T – Granular, Rough
C – Smooth, Glistening
Thrombus vs. PM Clot. Vascular endothelium?
T – Damaged, Rough
C – Smooth, Intact
Thrombus vs. PM Clot. Organization.
T – Partial
C – None
Thrombus vs. PM Clot. Structure.
T – Laminated.
C – Homogenous
Three primary causes of thrombosis.
Endothelial Injury (Most Common)
Alterations in Blood Flow
Hypercoagulability
Causes of endothelial injury leading to thrombosis?
Endocardium: Infar./myocarditis, Immune Rxn, valve prbs
Arteries: Atherosclerosis, Vasculitis
Radiation, Bacterial agents, catheter
Two types of blood flow alterations that can lead to thrombosis?
Turbulence (Arterial/Cardiac)
Stasis (Venous Thrombi)
Mechanism of blood flow alterations leading to thrombosis?
Stasis/Turbulence fuck up laminar flow. Platelets hit the endothelium. Coagulation factors aren’t diluted by fresh blood. Retard inflow of coag. inhibitor. Promote endothelial cell activiation
Four examples of alterations in normal blood flow
Aneurysms – Abnormal dilation of vessels
MI – Necrotic myofibers do not contract
Ulcerated atherosclerotic plaques – local turbulence
Hyperviscosity syndromes (polycythemia) – slow BF
Causes of primary hypercoagulability?
Factor V Leiden Prothrombin mutation Elevated homocysteine levels antithrombin III deficiency protein C deficiency, protein S deficiency Defects in fibrinolysis
Causes of secondary hypercoagulability?
Oral contraceptives -- increased synth of coag. factors Cancer -- tumor products Tissue damage -- stasis of injury site Aging -- increased platelet aggregation Heparin-induced thrombocytopenia antiphospholipid antibody (lupus)
What happens after a thrombus has formed
Propagation (grows larger – tail)
Detachment (embolization)
Stays attached
What do you do with a thrombus that stays attached?
Lysis
Retraction (incorporate into vessel walls)
Organization (endothelial growth over surface, hyalinization, Calcification)
Recanalization
Where do you typically see artherial thrombi?
Coronary, Cerebral, and Femoral Arteries
Significance of thrombi?
Obstruction – Infarction, Congestion
Embolization
What is an embolism?
Detached IV solid, liquid, or gasseous masses carrid by the blood stream to distant sites
Almost all emboli are…
Fibrinous thromboembolus
Sequale of Pulmonary emboli (not including silent ones)
Sudden Death – R Heart failure, CV collapse (big ones)
Pulmonary Hemorrhage (obs. of medium vessels)
Infarction - Obs. of small vessels
Pulmonary HTN – from multiple. leads to R sides HF
Almost all systemic emboli come from….
Others from…
Intracardiac mural thrombi (LV wall infarct, dilated atria, fib)
Aneurysms, Atherosclerotic plaques, Septal Defect
Whats it called when an emboli hits systemic circulation by goign through a septal defect?
Paradoxical emboli
List some causes of infarction
Thrombus/Thromboemboli Local vasospasm Tumor Torsion Edema causing vascular compromise
What is a white (anemic) infarcts
Arterial occlusion in solid tissue
What is a red (hemorrhagic) infarct
Venous occlusion
Tissues with dual blood supplies
Previously congested tissues, sluggish venous outflow
Microscopic features of infarcts
Coagulative necrosis (except brain), sharply demarcated
+/- occluded vessels, +/- congestion
Congestion and leukocyte influx in tissues
Fibrosis
Which type of thrombus is most prone to be occlusive
Venous
Name for the triad of endothelial injury, abnormal blood flow, and hypercoagulability
Virchow’s Triad
Common symptom of L sided embolism
Gangrene
Fat emboli are typically surrounded by cells from
Marrow
