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17 Cards in this Set
- Front
- Back
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What happens when there is an imbalance between fluid in the interstitial and intravascular compartments? |
Edema: accumulation of excess fluid in either interstitial space or body cavities. |
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4 Specific Mechanisms for Edema |
1. Increased vascular permeability 2. Increases intravascular hydrostatic pressure 3. Decreased plasma osmotic pressure 4. Decreased lymphatic drainage |
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What is the general mechanism for increased vascular permeability? |
Endothelial reaction to inflammation: - Vasoactive inflammatory mediators - Cause endothelial cell contraction and widening of gaps = fluid leakage - Localized or general |
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What is the general mechanism for increased intravascular hydrostatic pressure? |
Increased blood in the microcirculation due to congestion (passive accumualtion of blood) caused by venous obstruction (localized edema) or heart failure (general edema). |
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What is the general mechanism for decreased plasma osmotic pressure? |
Decreased albumin in the circulation, either due to decreased synthesis in the liver (malnutrition, intestinal malabsorption of protein, liver disease) or increased loss in the gut/kidney/skin (protein losing enteropathy, severe parasitism, protein losing nephropathy, burns) - Only generalized |
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What is the general mechanism for decreased lymphatic drainage? |
Blockage or compression of lymph vessels caused by tumours, swelling, fibrosis, clots etc - Localized |
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Is edema a transudate or exudate? |
Transudate. Clear pale yellowish thin fluid. |
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What is hyperemia? |
Increased volume of blood at a site due to arterial dilation - Active process - Tissues red - IE: muscle in exercise, inflammation
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What is congestion? |
Increased volume of blood at a site due to impaired blood flow away from a tissue - passive process - tissues redblue - IE: venous obstruction, heart failure - never normal! |
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Which tissues are most commonly affected by chronic congestion? |
Lungs and liver. In chronic congestion, capillaries may rupture which leads to multifocal hemorrhage. Parenchymal cells may atrophy or die = contraction and scarring. Chronic congestion may appear more brown due to RBC breakdown releasing hemosiderin. |
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What is hemorrhagic diathesis? |
The tendency to hemorrhage from insignificant injury. |
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What is petechiae? |
- Petechial hemorrhage - 1-2mm - In skin, MMs, serosal surfaces - Caused by increased intravasc pressure, clotting disorders, low platelets
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What is purpura hemorrhagica? |
- >3mm - In skin, MMs, serosal surfaces - Caused by increased intravasc pressure, clotting disorders, low platelets, trauma, vasculitis, vascular fragility |
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What are ecchymoses? |
- Ecchymotic hemorrhage (bruises) - >1-2cm - Subcu hematomas - Trauma, plus exacerbated by other conditions |
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What is it called when there is hemorrhage over a huge area? |
Suffusive hemorrhage |
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What happens if the liver is overwhelmed by the amount of hematoma? |
Jaundice/icterus because there is too much RBC breakdown which releases more bilirubin than the liver can metabolize, so it gets deposited into tissues. |
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How are hematomas resolved? |
- RBCs degraded by macrophages, the iron recycled Color progression: 1. Red/blue from hemoglobin 2. Blue/green from bilirubin and biliverdin 3. Golden brown from hemosiderin |
