Edema/Congestion/Hemostasis Flashcards
Edema definition
Increased fluid within interstitial tissues
Anasarca
Generalized and usually severe increase in fluid
What is the pathophysiology/causes of Edema?
Increase in hydrostatic pressure and/or decrease in venous return
Reduced plasma osmotic pressure - when stuff leaks out, fluid wants to leave vessels and go to the tissues
Lymphatic obstruction - struggle to return liquid so it goes out to the tissues
Na and H20 retention - if Na stays in the tissues, water will follow it
Inflammation - increased vascular permeability
What is a complication from pulmonary edema?
Impairs gas exhange
What is a complication from cerebral edema?
Compression and herniation of critical areas
Decreases blood flow
Effusion definition
Collection of fluid in body cavity or other space
Hyperemia definition
Increased tissue blood volume secondary to neurogenic mechanisms or inflammation (Active)
Congestion definition
Increased tissue blood volume secondary to impaired venous return (passive)
Often accompanied by edema
Hemorrhage definition
Loss of blood secondary to vessel injury or physical disruption
What are the different types of Hemorrhage?
External - bleeding, can be serious or minor
Internal
What are the different types of Internal Hemorrhage
Hematoma Ecchymosis Purpura Petechia Hemorrhage into body spaces
Hematoma
Large mass (tumor) of blood
Ecchymosis
≥ 1cm
Flat area of disruption
“Bruise”
Purpura
0.3-0.9 cm
Petechia
1-2 mm
Small, pinpoint
Often there are multiple
Can be indication of greater bleeding/blood issues
How do you name hemorrhage into a body space?
‘Hemo’ + the area
ie. Hemothorax, Hemopericardium, etc
Acute hemorrhage
Shock
Lose more than 20% of you blood volume (this is variable depending on the patient)
Chronic hemorrhage
More common than acute shock
Anemia is an example
Hemostasis definition
Rapid arrest of blood loss at site of injury
What are the 3 major components of Hemostasis?
Endothelium
Platelets
Coagulation cascade
How does the endothelium partake in hemostasis?
Has both anticoagulant and procoagulant properties
What are the 3 phases to forming the platelet plug?
Adhesion
Secretion
Aggregation
Adhesion
Mediated by von Willebrand Factor - which bridges between collagen and a surface platelet receptor (glycoprotein Ib)
Secretion
Release of contents from both types of granules
Platelets secrete ADP and Ca
ADP mediates platelet aggregation
Ca is required for the coagulation cascade
There is surface expression of a phospholipid complex, which is a binding site for Ca and coagulation factors
Aggregation
Simulated by ADP and Thromboxane A2
Thrombin derived from the coagulation cascade binds to a platelet surface receptor leading to more aggregation and platelet contraction
Fibrinogen binds to the plate let surface receptor GP IIb-IIIa and the platelet plug becomes cemented by fibrin
Coagulation Cascade
A series of enzymatic conversions of inactive proenzymes to active enzymes
The binding of calcium, active enzyme cofactor, and substrate (the proenzyme) occurs at the phospholipid complex on platelet membranes
Extrinsic system is activated by TF
Intrinsic system is activated by factor XII (Hageman factor)
Final products of both the intrinsic and extrinsic systems are thrombin and fibrin
Antithrombins
Control excess coagulation by inibiting the activity of thrombin (and other coagulation factors), and proteins C and S, which inactivate factors Va and VIIIa
Fibrinolysis
Occurs by the activation of plasmin from plasminogen by tissue plasminogen activator (t-PA)
Plasmin breaks down fibrin, resulting in fibrin split/degredation products
