edema, hyperemia and congestion. cardiovascular disease most important cause of morbidity and...
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Edema, Hyperemia and Congestion
Cardiovascular disease• Most important cause of morbidity and
mortality in developed nations
• In US, 81 million affected in 2005, causing 35 to 40% of deaths
• Components of cardiovascular system include Heart Vessels Blood
• Water, salts, proteins, clotting factors, cells
Blood• Hemodynamics
Edema• Water build-up in interstitial spaces and cavities• Hydrodynamic transudate is dilute, protein-poor• Inflammatory exudate is concentrated, protein rich
Hyperemia• Acute, actively increased blood flow—arteriole dilation,
increased heart rate– Tissues look red (erythema)
Congestion• Chronic, passively reduced outflow—venule dilation
– Tissues look pale or blue (cyanosis)
Shock• Circulatory failure
Fluids—water
0 20 40 60 80 100
total water
intracellular
interstitial
intravascular
Percentage lean body mass
Factors affecting intravascular and interstitial water movement
• Concentration of solutes Albumin and other proteins (huge difference) Sodium and other ions (small difference)
• Hydrostatic pressure Higher on arteriolar side Lower on venular side Lowest in interstitium
• Blood volume decreased b.p. Water intake/deprivation Water loss from skin or gut
• Perspiration, vomiting, diarrhea Blood loss; acute hemorrhage
Fluid transit
Edema• Localized or generalized accumulation of fluid in
interstitial spaces Anasarca: severe, generalized edema
• ana = throughout, sark = flesh• Most commonly used to describe fetal or neonatal whole-
body, subcutaneous swelling
• Effusions into body cavities Hydrothorax: within thorax, around lungs; also pleural
effusion Hydropericardium: Fluid in the pericardial sac Hydroperitoneum or ascites: Fluid in the peritoneal
cavity
• Extravasate: (v.) to move out of the vasculature
Responses to edema
• Skin:swells according to elasticity dependent edema: distribution affected by
gravity (ankles, sacrum) dependent = hanging down in this context
• Brain: compresses without room to swell
• Lung: alveoli fill preventing gas exchange
Appearance of edema
• Swollen tissues (not cells—fluid is outside the cells)
• Heavy tissues
• Wet tissues
• Widening of fascial planes or interlobular septa
• Filled cavities
Causes of edema• Increased hydrostatic pressure
Focal impairment—deep vein thrombosis Generalized impairment—right heart failure
• Decreased plasma osmotic pressure Hypoproteinemia
• Decreased protein synthesis—serum albumin• Increased protein loss to nephrotic syndrome
• Sodium (and water) retention• Increased capillary permeability
• inflammation or injury (burns)
• Lymphatic obstruction• Filariasis, breast carcinoma
Appearance and causes of hyperemia
• Increased flow of blood into tissue• Local process of arteriole dilation greater
than venule dilation• Appearance of blood flow is RED• Normal physiological examples:
Exercise Blushing Erection Inflammatory response (rubor)
• Small contribution to edema
Congestion
• Impaired venous outflow from tissue
• Local increases in venous pressure
• Central congestive heart disease increases diastolic (venous) b.p.
• Right-side failure congests portal drainage, liver, generalized edema
• Left-side failure congests pulmonary drainage, lungs, hypoxemia
Congestive heart failure• Right side failure—volume backs up behind
pulmonary circulation Generalized edema Portal edema—nutmeg liver
• Left side failure—volume backs up behind systemic circulation Pulmonary edema and pleural effusion
• Distension of alveolar capillaries leading to capillary rupture and red cells in alveoli
• Intra-alveolar macrophages phagocytose red cells and accumulate hemosiderin
• Fibrosis of the interstitium with hemosiderin deposition• Serous or serosanguinous effusions surrounding lungs
Congestive heart failure
• Reduced cardiac output
• Renal hypoperfusion
• Activation of renin-angiotensin-aldosterone axis Early response is beneficial
• sodium and water retention increased vascular toneelevated antidiuretic hormone (ADH) improved cardiac outputrestored renal perfusion
Ongoing response increases edema• Volume of blood exceeds volume of vasculature• Fluids build up in tissues
Anasarca
Hyperemia, injury
Trivial and life-threatening edema
Pitting edema
Elephantiasis--lymphedema
Peau d’orange and post-mastectomy lymphedema
Ascites due to portal congestion
Nutmeg liver
Hepatic congestion
Effusions• Extravascular fluid collections can be classified as
follows: Exudate: extravascular fluid collection that is rich in protein
and/or cells. Fluid appears grossly cloudy. Transudate: extravascular fluid collection that is basically an
ultrafiltrate of plasma with little protein and few or no cells. Fluid appears grossly clear.
• Effusions into body cavities can be further described as follows: Serous: a transudate with mainly edema fluid and few cells. Serosanguinous: an effusion with red blood cells. Fibrinous (serofibrinous): fibrin strands are derived from a
protein-rich exudate. Purulent: numerous PMN's are present. Also called "empyema"
in the pleural space.
Pleural effusions and edema
Fibrinous exudate
Pleural effusion
Pleural effusion
Pulmonary edema
Dilated lymphatic vessels
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