EDEMA

Edema

Definition

An abnormal accumulation of fluid in the interstitial tissue is known as edema.

Fluid collections in the  body cavities are known as effusion

•      Hydrothorax or pleural effusion

•      Hydropericardium or pericardial effusion

•      Hydroperitoneum or ascites

•      Normally fluid movement between vascular space and interstitial tissue is controlled by

•      Vascular Hydrostatic pressure

•      governed by blood flow

•      ­ in pressure moves fluid out of the vessel

•      Plasma colloid osmotic pressure

•      plasma proteins maintains osm.pressure

•      ­ in osm. Pressure maintains  fluid within the vascular space

1.     Causes of Edema
INCREASED HYDROSTATIC PRESSURE

•      Impaired venous return e.g. Congestive heart failure; cirrhosis

•      Venous obstruction or compression

2. REDUCED PLASMA OSMOTIC PRESSURE (HYPOPROTEINEMIA)

•      Liver cirrhosis; Malnutrition   

3.  LYMPHATIC OBSTRUCTION

•        inflammation; Neoplasm

4. INFLAMMATION

•          Acute inflammation

•          Chronic inflammation   

5. SODIUM RETENTION

•      Renal failure

•      Increased tubular reabsorption

Type of edema

•      Trasudate

–     ultrafiltrate of blood plasma and contains little protein

–    Conditions with increased hydrostatic pressure or decreased oncotic pressure

–    Specific gravity  <1.012

•      Exudate

–    edema fluid rich in protein

–    Conditions associated--Inflammation

–    specific gravity > 1.020.