Edema

CONTENTS:
GENERAL
NORMAL FLUID CIRCULATION
EDEMA- INTRODUCTION
CAUSES
CLASSIFICATION
MAJOR TYPES
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1. EDEMA KANAV BHANOT ROLL NO. 05

2. CONTENTS GENERAL NORMAL FLUID CIRCULATION EDEMA- INTRODUCTION CAUSES CLASSIFICATION MAJOR TYPES

3. GENERAL 60% of body’s weight is water. 2/3 rd of it is INTRACELLULAR and 1/3 rd is EXTRACELLULAR. EXTRACELLULAR is further divided into Intravascular, Interstitial & Trans vascular

4. NORMAL FLUID CIRCULATION The movement of fluid between vasculature is controlled by opposing effects of “Vascular Hydrostatic Pressure” & “Plasma Colloid Osmotic Pressure”. Hydrostatic Pressure is more at the Arteriolar end whereas Oncotic pressure is more at the Venous end. Exit of fluid from arteriolar end is balanced by inflow at venular end of microcirculation. Small residual amount of excess interstitial fluid is drained by lymphatics.

5. EDEMA Edema is an abnormal accumulation of fluid in the interstitium, located beneath the skin and in the cavities of the body. Edema is a normal response of the body to inflammation or injury. For example, a twisted ankle, a bee sting, or a skin infection will all result in edema in the involved area. In some cases, such as in an infection, this may be beneficial. Increased fluid from the blood vessels allows more infection-fighting white blood cells to enter the affected area.

6. CAUSES Five factors can contribute to the formation of edema : Increased hydrostatic pressure; Reduced plasma oncotic pressure Increased blood vessel wall permeability e.g. INFLAMMATION ; Obstruction of fluid clearance in the lymphatic system; Changes in the water retaining properties of the tissues themselves. Raised hydrostatic pressure often reflects retention of water and sodium by the kidney

7. 1. INCREASED CAPILLARY HYDROSTATIC PRESSURE Rise in hydrostatic pressure at the venular end of capillaries to a level more than plasma oncotic pressure ↓ Minimal / No reabsorption of fluid at venular end ↓ EDEMA

8. 2. Reduced Plasma Oncotic Pressure Reduced albumin synthesis in liver / protein malnutrition ↓ Fall in plasma oncotic pressure ↓ Net movement of fluid into interstitial tissues ↓ EDEMA

9. 3. INFLAMMATION Capillary endothelial injury by toxins/ histamine/ anoxia/ drugs ↓ Endothelial gap ↓ ↑ Capillary permeability to plasma proteins ↓ ↓Plasma oncotic pressure ↓ EDEMA

10. 4. LYMPHATIC OBSTRUCTION Impaired lymphatic drainage ↓ Localized LYMPHOEDEMA (E.g.:-Radical mastectomy for Ca breast; Pressure on main lymph ducts; Inflammation of lymphatics; Occlusion of lymphatics by malignant cells; Filariasis)

11. 5 . SODIUM & WATER RETENTION Hypovolemia ↙ ↓ ↘ Renal Vasoconstriction Renin ↑ADH ↓ ↓ ↓ ↓GFR Aldosterone Reabsor. of H2O ↓ ↙ Renal Retention Of Na & Water ↓ Edema

12. CLASSIFICATION Edema can be classified as GENERALISED or LOCALISED . GENERALIZED EDEMA is a condition when you notice swelling, puffiness, and water retention in various body parts, including your abdomen, arms, legs, face, and feet. Symptoms include bloating, tightening of skin, and skin that holds an imprint or looks pitted Conditions leading to generalised edema: Congestive Heart Failure Nephrotic syndrome Cirrhosis of Liver Systemic Infection etc.

13. LOCALISED EDEMA can be defined as the type of edema confined to a particular part/organ of the body. Various conditions that lead to localised edema are: Trauma Infection Lymphatic Obstruction like Filariasis Venous Obstruction (e.g.- thrombosis)

14. Edema can also be classified as PITTING or NON-PITTING . Cutaneous edema is referred to as “PITTING" when, after pressure is applied to a small area, the indentation persists after the release of the pressure. Peripheral pitting edema is the more common type, resulting from water retention. It can be caused by systemic diseases, pregnancy in some women, either directly or as a result of heart failure , or local conditions such as varicose veins, thrombophlebitis , insect bites, and dermatitis. “NON-PITTING EDEMA” is observed when the indentation does not persist. It is associated with conditions such as lymphedema, lipedema, and myxoedema .

15. MAJOR TYPES There are different types of edema. Some of them are specific to certain parts of the body, while others may be more generalized. Edema can be majorly classified into following types: PERIPHERAL EDEMA PULMONARY EDEMA CEREBRAL EDEMA

16. a. PERIPHERAL EDEMA Peripheral edema mainly occurs in the legs, feet, and ankles. This is the most common type of edema and it causes swelling in the lower extremities. This type of edema may be caused by increasing age, pregnancy, hypertension, congestive heart failure, kidney problems or other health conditions. You also may experience peripheral edema if you have been sitting or standing for extended hours. Some medications may also cause peripheral edema: NSAIDs (ibuprofen, naproxen) Corticosteroids (prednisone, methylprednisolone)

17. b. PULMONARY EDEMA Pulmonary edema is the accumulation of fluids in the lungs due to the blockage of the pulmonary veins. As blood pressure rises in the blood vessels of the lungs, fluids rush in to fill the lungs . The pleural cavity can also be filled with fluid. In such cases, the pulmonary edema is said to also present with pleural effusion . Pulmonary edema is usually caused by the malfunctioning of the left ventricle of the heart (leads to ↑sed pulm. vein pressure which causes ↑sed hydrostatic pressure). Other causes can be: Acute Respiratory Distress Syndrome. Hypersensitivity Reaction (Pink Frothy Sputum is the classical symptom of this edema.)

18. c. CEREBRAL EDEMA In cerebral edema, fluids accumulates in the intracellular and extracellular spaces of the brain. It can be caused by metabolic abnormalities due to an underlying disease or as a response to oxygen deprivation at high altitudes. Cerebral edema is a very serious form of edema. It can lead to loss of consciousness and brain damage . Cerebral edema can be further divided into 3 subtypes of edema. These are : Vasogenic Cytotoxic Interstitial cerebral edema.

19. Vasogenic cerebral edema occurs when the blood-brain barrier breaks down. This allows plasma to leak into the brain, first reaching the white matter before getting to the grey matter. This type of cerebral edema is caused by tumour, trauma or cardiovascular events. Cytotoxic cerebral edema is caused by the malfunctioning of the sodium and potassium pump of the glial cells. This leads to the accumulation of sodium and water and then the swelling of the gray and white matter. The blood-brain barrier is unaffected in cytotoxic edema. Interstitial edema occurs when the barrier between the brain and the cerebrospinal fluid ruptures. This causes the inflow of cerebrospinal fluid into the brain and its accumulation in the white matter and extracellular spaces.