Fluid and Hemodynamic Disorders - Final Exam Flashcards
Edema
Fluid in tissues
Localized or systemic
Capillary hydrostatic pressure
Pressure in capillary due to heart pumping and weight of blood
Capillary oncotic pressure
Pressure in capillary due to proteins present in fluids
Proteins in blood cannot cross normal capillary wall
Lymphatic system
A network of vessels separate from blood circulation that carry lymphatic fluid
Blood components (4)
- Water
- Electrolytes
- Cells
- Proteins
Electrolytes in blood
Na, K, Ca etc
Proteins in blood
Albumin, coagulation proteins etc
Albumin
Maintains oncotic pressure
Made by liver
Involved in transportation of: steroids, thyroid hormone, bilirubin, bile salts, fatty acids
Two main drivers of fluid movement across capillary wall
- Capillary hydrostatic pressure
2. Capillary oncotic pressure
Lymph fluid entering venous sytem***
Thoracic duct/right lymphatic duct
Arteriole
Site of filtration
Fluid leaves
Venule
Site of reabsorption
Fluid comes back
Pericyte
Vascular supportive cell
Components of normal capillary wall
Basement membrane
Endothelial cells
How can we tell if a vessel is a lymphatic vessel?
Only lymphatic fluid and lymphocytes
No RBC
Causes of localized edema (3)
- Ischemia - irreversible cell injury, causing release of chemical mediators
- Infection - chemical mediators released by WBC
- Lymphatic obstruction - obstruction or damage of small or large lymphatic vessels, usually by treatment for carcinoma
Endothelial cell retraction
Endothelial cells retract from each other in response to chemical mediators
Can be reversible
Endothelial cell injury
More severe damage results in endothelial cell necrosis and detatchment
Not reversible
Causes of localized edema- ischemia
Cell lysis, irreversible cell injury, causing release of chemical mediators
Causing cells to retract and capillary to become leaky
Causes of localized edema- infection
Neutrophils resppond to infection (ie. bacteria)
Neutrophils inside and outside of capillary release signals to make capillary leaky
Impetigo
Staphylococcus aureus invades and replicates in skin
Causes of localized edema- inflammation
ie. Crohn’s Disease
in ileum, causing dilution of lymphatic vessels
Causes of local edema- lymphatic obstruction
Obstruction of lymphatic vessels, fluid is not re-absorped and also forced out
Subcapsular sinus
Where afferent lymph vessel enters lymph node
Afferent lymphatic vessels
Bring lymphatic fluid to lymph node
Efferent lymphatic vessels
Take lymphatic fluid from lymph node
Example of localized edema - breast carcinoma therapy
Axillary lymph node dissection
Causes left arm edema
Lymph node dissection
Surgical identification and removal of lymph nodes for purposes of treatment and/or staging of tumor
Staging
A system of describing how advanced a tumor is in a patient
Axillary
Armpit
Causes of systemic edema (3)
- Heart failure
- Kidney Disease
- Liver failure
Heart failure causing systemic edema
Left heart failure causes edema in lungs
Right heart failure causes edema in legs
Increased hydrostatic pressure from impaired venous return
Heart is unable to pump enough blood to adequately perfuse tissues
Fluids will back up according to which ventricle is affected
Kidney disease causing systemic edema
Loss of albumin in urine
Retention of sodium and water
Liver failure causing systemic edema
Not enough albumin produced, decreasing oncotic pressure in capillaries
Ascites
Caused by cirrhosis of liver
Accumulation of fluid in abdomen
Cirrhosis
Fibrosis of liver
Systemic edema
Fluid edema that is not localized
Refers to edema caused by heart failure, kidney disease or liver failure
Systemic circulation
Blood circulation other than heart and lungs
Left heart failure
Pressure increases in pulmonary veins
Hydrostatic pressure increases in pulmonary capillary bed and causes fluid to enter lungs
Pulmonary edema
Fluid build up in lungs
Can be heard as crackles with stethoscope at base of lungs
Right heart failure
Pressure increases in vena cavae
Hydrostatic pressure increases in systemic capillary bed and causes fluid to enter systemic (leg) tissues
Pitting edema
In legs due to right heart failure
Pressing on skin will leave indentation
Why does fluid accumulate at bottom of lungs and legs?
Subject to gravity
Glomeruli
Part of kidney where blood filtration occurs
Kidney disease
Damage to basement membrane in glomeruli
Albumin can cross and be released into urine
Low albumin causes fluid to enter into tissues (decreased oncotic pressure) causing systemic edema
Liver failure (2)
- Liver not producing enough albumin
2. Liver not producing enough clotting factors
Coagulation cascade
Proteins in blood that participate and regulate thrombus formation
Thrombin cleaves fibrinogen into fibrin - causes stabilization of coagulation plug
Thrombus
Blood clot
Composed of platelets and fibrin
Entraps RBC and WBC
Forms are site of blood vessel injury
Thrombo-embolus
A piece of thrombus has broken off and and travelled elsewhere in body
Hypercoagulable state
A condition where the blood will clot very easily
Atherosclerosis
Disease of the arteries
Fatty deposite and calcification in arterial wall
Hardening
Plaques are potential sites of thrombus formation
Atrial fibrillation
Disease of the heart
Uncoordinated chaotic contraction of atrium causes areas of irregular blood flow
Thrombus can form at sites of poor blood flow, such as on surface of left atrial appendage - can break loose and embolize and cause infarction
Hemostasis
Coagulation
Process of thrombus formation at site of blood vessel injury to make bleeding stop
Three components that control thrombus formation
- Endothelial cells: damage causes platelets to adhere and form plugs
- Platelets: aggregate and form plug at site of injury
- Coagulation cascade: thrombin cleaves fibrinogen into fibrin, which stabilizes platelet plug
Lamination
Layers form in thrombus due to blood flood
RBC get trapped
Platelets
Produced by megakaryocytes in bone marrow
Released into blood until needed for thrombus formation
Causes of pathological thrombi (3)
- Endothelial cell injury
- Poor blood flow
- Hyper-coagulable state
These are all activating components of hemostasis system
Causes of arterial thrombi (2)
- Atherosclerosis
2. Atrial fibrillation
Potential thrombo-embolic consequences of arterial thrombi (3)
- Myocardial infarction
- Cerebral infarction
- Kidney infarction
Causes of venous thrombi (4)
- Venous stasis
- Cancer
- Pregnancy
- Inherited thrombophilia
Venous stasis
Poor blood flow, can cause venous thrombus
Can occur in any vein, but mainly legs
Immobilization is risk factor (air travel, surgery)
Cancer
Causes hypercoagulable state
Can cause venous thrombus
Can release pro-coagulaent factors like cytokines and clotting system activators
Inherited thrombophilia
Causes hypercoagulable state
Genetic abnormalities in coagulation proteins
Can cause venous thrombus
Potential thrombo-embolic consequecnes of venous thrombi
Pulmonary emboli - venous thrombus breaks off from its origin and end up in lungs
Pleural based infaction
Caused by small thromboembolus in branch of pulmonary artery
Shock
Circulatory failure that results in poor tissue perfusion resulting in cellular hypoxia
Three types of circulatory failures
- Cardiogenic shock (myocardial infarction)
- Hypovolemic shock (trauma, blood loss)
- Septic shock (systemic inflammatory response, usually infection)
Cardiogenic shock (pump failure)
Myocardial infarction, ventricular rupture, pulmonary embolism
Tissues are not getting enough blood because heart is not pumping properly
Hypovolemic shock (fluid loss)
Hemorrhage, vomiting/diarrhea
Tissues are not getting enough blood as there is not enough blood volume
Septic shock (systemic imflammatory response)
Due to infection
Systemic vasodilation
Tissues are not getting enough blood because peripheral blood vessels are markedly dilated
Complications of shock (2)
- Acute respiratory distress sydrome
2. Disseminated intravascular coagulation
Acute respiratory distress syndrome
Damage to pulmonary capillary endothelium and alveolar epithelium causes edema to enter pulmonary alveoli
Damage is secondary to many things (aspiration, pancreatitis, smoke, toxic gas)
Phases of acute respiratory distress syndrome
Acute: alveolar edema
Later: progression to hyaline membranes and thickened alveolar walls
Disseminated intra-vascular coagulation
Complication of shock
Caused by excessive activation of coagulation and formation of thrombi in microvasculature of body
Causes consumption of coagulation factors and platelets causing bleeding in other parts of body
