Edema Pathophysiology PDF

Pathomedicine Module Edema Aaron E. Yancoskie, D.D.S. Diplomate, American Board of Oral and Maxillofacial Pathology  Body Fluid 60% of lean body weight is water 100% of water – ~66% intracellular – ~28% extracellular – ~5% p...

Pathomedicine Module Edema Aaron E. Yancoskie, D.D.S. Diplomate, American Board of Oral and Maxillofacial Pathology  Body Fluid 60% of lean body weight is water 100% of water – ~66% intracellular – ~28% extracellular – ~5% plasma Edema is an abnormal accumulation of fluid in tissue – Special terms describing edema Hydrothorax – Edema in the pleural cavity Hydropericardium – Edema in the pericardial cavity Hydroperitoneum or ascites – Edema in the peritoneal cavity Anasarca – Severe generalized edema including » Swelling of subcutaneous tissues » Edema of body cavities  Edema Inflammatory edema – Covered in prior material – Primarily related to increased vascular permeability Mostly produces edema that is an exudate (protein-rich) – Specific gravity » Greater than 1.020 Non-inflammatory edema – Determined by balance (or lack thereof) between two opposing forces Vascular hydrostatic pressure Colloid osmotic pressure – Produces edema that is a transudate (protein-poor) » Specific gravity Less than 1.012  Normal Robbins Basic Pathology, 9th Edition. PP 78. Fig 3-2. - Outflow of fluid produced by hydrostatic pressure at arterial end - Balanced out by slightly elevated osmotic pressure at venous end - Increase in interstitial fluid accumulation results in increased interstitial fluid pressure and aids in returning fluid to the vasculature - Excess is drained by lymphatics and returned to the circulation via the subclavian vein  Hydrostatic pressure Increased Favors movement of fluid out of vasculature Decreased Favors fluid staying in the vasculature Colloid osmotic pressure Increased Favors fluid staying in the vasculature Decreased Favors movement of Robbins Basic Pathology, 9th Edition. PP 78. Fig 3-2 fluid out of the vasculature  Hydrostatic pressure Increased Favors edema Decreased Does not favor edema Colloid osmotic pressure Increased Does not favor edema Decreased Robbins Basic Pathology, 9th Edition. PP 78. Fig 3 Favors edema  Increased Hydrostatic Pressure Impaired venous return – Localized example Deep venous thrombosis (DVT) in lower leg – Occlusion of vessel and increases hydrostatic pressure in vessel » Results in edema of related area of leg  Increased Hydrostatic Pressure Impaired venous return – Localized example Deep venous thrombosis (DVT) in lower leg – Occlusion of vessel and increases hydrostatic pressure in vessel » Results in edema of related area of leg Arterial end Venous end Capillary bed  Increased Hydrostatic Pressure Impaired venous return – Localized example Deep venous thrombosis (DVT) in lower leg – Occlusion of vessel and increases hydrostatic pressure in vessel » Results in edema of related area of leg Thrombus Arterial end Venous end Capillary bed  Increased Hydrostatic Pressure Impaired venous return – Localized example Deep venous thrombosis (DVT) in lower leg – Occlusion of vessel and increases hydrostatic pressure in vessel » Results in edema of related area of leg Thrombus Arterial end Venous end Capillary bed  Increased Hydrostatic Pressure Impaired venous return – Localized example Deep venous thrombosis (DVT) in lower leg – Occlusion of vessel and increases hydrostatic pressure in vessel » Results in edema of related area of leg Thrombus Increased pressure = drives fluid out Arterial end Venous end Capillary bed  Increased Hydrostatic Pressure Impaired venous return – Localized example Deep venous thrombosis (DVT) in lower leg – Occlusion of vessel and increases hydrostatic pressure in vessel » Results in edema of related area of leg Thrombus Increased pressure = drives fluid out Color Atlas and Text of Medicine 3rd Edition. Fig 5.20.1. PP. 253. Arterial end Venous end Capillary bed  Increased Hydrostatic Pressure Impaired venous return – Systemic example Heart failure – Diminished cardiac output – Essentially same concept as occluding venous return » Results in edema of tissues Increased pressure = drives fluid out Broken Color Atlas and Text of Medicine 3rd Edition. Fig 5.6. PP 200. Arterial end Venous end Capillary bed  Reduced Plasma Osmotic Pressure Diminished albumin – Example Damaged kidneys – Loss of plasma proteins » Results in generalized edema Color Atlas and Text of Medicine 3rd Edition. Fig 5.6. PP 200. Arterial end Venous end Capillary bed  Reduced Plasma Osmotic Pressure Diminished albumin – Example Damaged kidneys – Loss of plasma proteins » Results in generalized edema Color Atlas and Text of Medicine 3rd Edition. Fig 5.6. PP 200. Arterial end Venous end Capillary bed  Reduced Plasma Osmotic Pressure Diminished albumin – Example Damaged kidneys – Loss of plasma proteins » Results in generalized edema Color Atlas and Text of Medicine 3rd Edition. Fig 5.6. PP 200. Arterial end Venous end Capillary bed  Reduced Plasma Osmotic Pressure Diminished albumin – Example Damaged kidneys – Loss of plasma proteins » Results in generalized edema Fluid follows albumin Color Atlas and Text of Medicine 3rd Edition. Fig 5.6. PP 200. Arterial end Venous end Capillary bed  Reduced Plasma Osmotic Pressure Diminished albumin – Example Cirrhosis – Insufficient production of albumin by the liver » Results in generalized edema Color Atlas and Text of Medicine 3rd Edition. Fig 5.6. PP 200. Arterial end Venous end Capillary bed  Reduced Plasma Osmotic Pressure Diminished albumin – Example Cirrhosis – Insufficient production of albumin by the liver » Results in generalized edema Insufficient albumin to retain fluid in vasculature Color Atlas and Text of Medicine 3rd Edition. Fig 5.6. PP 200. Arterial end Venous end Capillary bed  Edema as a Result of Lymphatic Obstruction Inflammatory conditions – Filariasis (elephantiasis) Parasitic infection that results in lymph node (LN) fibrosis – Blockage leads to enlargement of » Lower extremities » External genitalia Neoplastic conditions – Metastatic cancers may lodge in LNs Peau d’orange (orange peel) appearance of skin – Finely pitted edema – Often seen in breast cancers Both conditions prevent drainage of interstitial fluid and result in edema  Self Study Page 76-78 Robins Basic Pathology, 9th edition.