Edema Flashcards
Escape of Fluid
Edema
Escape of cellular elements of blood
Hemorrhage
Undesired clotting of blood
Thrombosis
Detached intravascular mass
Embolism
Ischemic necrosis
Ischemia
Tissue injury secondary to systemic hypotension
Shock
Water accounts for ____ % of the lean body weight
60 %
Is most water of the body in extracellular or intracellular spaces?
Intracellular
Residual fluid left in the interstitium is drained by _______
Lymphatic vessels
How much fluid (ml/min) is moved out from arteries to tissues?
14 ml/min
How much fluid (ml/min) is moved in from tissues to veins?
12 ml/min
How much fluid is drained via the lymphatic system (ml/min)?
2 ml/min
Accumulation of interstitial fluid within the tissues
–Edema
= pleural effusion
Hydrothorax
= pericardial effusion
Hydropericardium
=ascites (alcoholic cirrhosis)
Hydroperitoneum
–High specific gravity
–Protein rich
–Inflammatory edema
•Exudate
–Low specific gravity
–Protein poor
–Volume or pressure overload
–Reduced plasma protein
Transudate
- Lymphatic spread of bacterial infection
* Painful red streaks and regional lymphadenopathy
Lymphangitis
–Increase in fluid in the interstitial space caused by an abnormality in the lymphatic system
–Lymphatic fluid collects in tissues causing edema
–May be congenital or acquired
•Acquired
•Congenital
Lymphedema
- Parasitic tropical disease
- Mosquito vector
- Nematode (roundworm) -Wuchereriabancrofti
- Lymph node fibrosis, lymph stasis and chronic lymphedema
- Elephantiasis
Lymphatic Filariasis
- Angiosarcoma arising from chronic lymphedema
* Long-standing lymphedema secondary to surgical lymph node dissection and/or radiation therapy
Stewart-Treves Syndrome
Severe, generalized edema
Ansarca
- Congestion in systemic and portal venous circulations •Congestive hepatomegaly -chronic passive congestion -“nutmeg” liver
- Congestive splenomegaly
- Pleural effusion
- Peripheral edema -pitting edema
Right-sided edema
- Increased intra-cranial pressure may result in herniation of cerebellar tonsils through the foramen magnum
- Compression of the medulla depression of the centers for respiration and cardiac rhythm control
Cerebral Edema
_____ edema is usually caused by –Increased vascular permeability (injury-inflammation)–Obstruction of venous or lymphatic outflow
Localized
_______ edema is generally caused by decreased plasma osmotic pressure
Generalized
Generalized edema is generally caused by decreased ________
plasma osmotic pressure
Severe swelling and edema of the entire body is called: A.Ascites B.Transudate C.Effusion D.Anasarca
Ansarca
What are the 5 pathophysiologic categories of edema?
Increased hydrostatic pressure Decreased plasma osmotic pressure Lymphatic obstruction Sodium retention Inflammation
Arteriolar dilation leads to increased blood flow
–Active process
–Sites of inflammation
–Skeletal muscle during exercise
•Affected tissues turn red (erythema) because of engorgement of vessels with oxygenated blood
Hyperemia
- Reduced outflow of blood from a tissue (stasis)–Passive process–Impaired venous drainage dilation of venules and capillaries
- Congested tissues take on a dusky, reddish-blue color (cyanosis) due to red cell stasis and accumulation of deoxygenated hemoglobin
Deep venous thrombosis
Compression of superior vena cava by neoplasm obstructing venous return
Superior Vena Cava syndrome
= extravasation of blood into the extravascular space
Hemorrhage
____ hemorrhage =rupture of a large vessel secondary to injury –Trauma, atherosclerosis, erosion of a vessel wall (inflammation or neoplasia)
Severe hemorrhage
___________ =increased tendency to hemorrhage –occurs in a variety of clinical disorders
Hemorrhagic diathesis
: pinpoint hemorrhages
Petechiae
: petechiae become confluent> 0.3 cm
Purpura
:purpurae become confluent> 1.0 cm
Ecchymosis
: a physiologic process that maintains blood in a fluid state in normal vessels, yet also permits the rapid formation of a hemostatic clot at the site of a vascular injury
Hemostasis
: pathologic counterpart of hemostasis that involves blood clot (thrombus) formation within intact vessels
Thrombosis
____ hemostasis is associated with platelet plug
Primary hemostasis
______ hemostasis is associated with fibrin clot
Secondary hemostasis
_____ hemostasis: formation of hemostatic plug–Highly thrombogenic sub-endothelial matrix exposed–Platelet adherence and activation–Shape change from small, round disks to flat plates with markedly increased surface area–Release of secretory granules–Recruitment of additional platelets (aggregation)
Primary hemostasis
- Most common hereditary bleeding disorder•Group of bleeding disorders
- Quantitative or qualitative abnormality of the von Willebrand factor (vWF)
- vWF is a platelet adhesion molecule required for normal platelet adhesion
- vWF is the carrier protein for factor VIIIsite of injury
Von Willebrand Disease
•Compound defect involving both platelet function and coagulation pathway
von Willebrand Disease
- Balance between antithrombotic and prothrombotic properties of endothelium determines whether thrombus formation, propagation or dissolution occurs
- Normally exhibit antiplatelet, anticoagulant and antifibrinolytic properties
- May be activated by trauma, infectious agents, hemodynamic forces, plasma mediators and cytokines
- After activation, endothelial cells acquire procoagulant activities
Endothelial Cells
What are the 3 factors leading to thrombosis (Virchow’s triad)?
Endothelial injury
Stasis or turbulent flow
Hypercoagulability of the blood flow
____- thrombi–Heart chambers or aortic lumen
Mural thrombi
_______ thrombi–Frequently occlusive–Most common: Coronary, cerebral, femoral arteries–Superimposed on ruptured, ulcerated atherosclerotic plaque
Arterial thrombi
______ thrombi –Usually occlusive: thrombus forms a long cast of the lumen–Veins of lower extremities
Venous thrombi
_______ thrombi–Begin at sites of turbulence or endothelial injury–Propagate away from the heart
Arterial or cardiac thrombi
_______ thrombi–Occur at site of stasis–Propagate toward the heart
Venous thrombi
- Thrombi often have grossly and microscopically apparent laminations called_______
- Pale platelet and fibrin deposits alternating with darker red cell-rich layers
- Laminations signify that a thrombus has formed in flowing blood
- Their presence can distinguish antemortem thrombosis from the bland, non-laminated clots that occur postmortem
lines of Zahn
Fate of thrombus: fibrinolysis
Dissolution
Fate of thrombus: accumulate additional platelets and fibrin
Propagation
Fate of thrombus: dislodge and travel to other sites in the vasculature
Embolization
_____ thrombi:
-Embolize to lungs and cause death
Venous thrombi
_____ thrombi:
Embolize and cause downstream infarctions
Arterial thrombi
_____ thrombi:
–Cause local congestion, swelling, pain and tenderness
–Rarely embolize
Superficial venous thrombi
_____ thrombi:
–Cause local pain and edema –rapidly offset by collateral channels–More often embolize to lungs–Half are asymptomatic, recognized in retrospect after embolization
Deep venous thrombi
- Widespread fibrin thrombi in the microcirculation–not grossly visible but can be seen microscopicallyplatelet and coagulation protein consumption (consumptive coagulopathy)
- May cause diffuse circulatory insufficiency–brain, heart, lungs, kidneys
- Fibrinolytic mechanisms are activated
- Initial thrombotic disorder can evolve into a bleeding disorder
- Not a primary disease but a potential complication of any condition associated with widespread activation of thrombin–E.g. advanced malignancy, obstetric complication
Disseminated Intravascular Coagulation
- A detached intravascular solid, liquid or gaseous mass that is carried by the blood to a site distant from its point of origin
- Lodge in vessels too small to permit further passage and cause partial or complete occlusion –Major consequence is ischemic necrosis (infarction) of the downstream tissue
Embolus
_____ emboli:
–tend to lodge in one vascular bed (lung)
Venous emboli
_____ emboli:
–can travel to a wide variety of sites
–Point of arrest depends on source and relative amount of blood flow
–^ in lower extremities and brain
–Consequences depend on vulnerability of tissue to ischemia, caliber of occluded vessel and collateral blood supply
Arterial emboli
An embolus that originates on the right side venous circulation and bypasses lung lodges in the left side systemic arterial circulation
Paradoxical embolus
–Restriction in blood supply, usually due to factors in the blood vessels–Lack of oxygen, glucose and other bloodborne materials tissue damage
Ischemia
–Complete loss of blood supply, resulting in necrosis
–Ischemic necrosis
Infarct
–More general term denoting a shortage of oxygen
–Usually a result of lack of oxygen in the air being breathed
Hypoxia
