Edema

Extravasation of fluid into interstitial space

Can be mild to life threatening

e.g. – edema after minor trauma in extremities to pulmonary edema

ANASARCA= Severe, generalized edema of the whole body.

HYDROTHORAX= Excessive fluid in the pleural cavity.

HYDROPERICARDIUM= Excessive fluid in the pericardial cavity.

HYDROPERITONEUM= Excessive fluid in the peritoneal cavity. Also called ASCITES

Distribution of water in human body

2/3rd law:

Total water: 2/3rd of lean body weight

ICF: 2/3rd of total body water

ECF: 1/3rd of total body water

Interstitial fluid: 2/3rd of ECF

Plasma: 1/3rd of ECF

Pathophysiologic Classification of Edema

Increased Hydrostatic Pressure

Impaired venous return

Congestive heart failure

Constrictive pericarditis

Venous obstruction or compression

Thrombosis

External pressure (e.g., mass)

Lower extremity inactivity with prolonged dependency

Arteriolar dilation

Heat

Neurohumoral dysregulation

Reduced Plasma Osmotic Pressure (Hypoproteinemia)

Nephrotic syndrome

Liver cirrhosis

Malnutrition

Protein losing enteropathy

Lymphatic Obstruction

Inflammatory

Neoplastic

Postsurgical

Postirradiation

Sodium Retention

Excessive salt intake with renal insufficiency

Increased tubular reabsorption of sodium

Renal hypoperfusion

Increased renin-angiotensin-aldosterone secretion

Inflammation

Acute inflammation

Chronic inflammation

Angiogenesis

Microscopic

Gross – pitting and non-pitting

Pitting – Extra lymphatic cause

Non-pitting – Lymphatic cause

edema fluid is reflected primarily as a clearing and separation of the extracellular matrix elements with subtle cell swelling

Any organ or tissue in the body may be involved-- subcutaneous tissues, lungs, and brain with potential spaces (pleural, pericardial and peritoneal) are the most common ones

SUBCUTANEOUS EDEMA:

Usually seen in dependent areas of the body due to gravity. Also, when pressure applied by finger the fluid is displaced leaving a finger-shaped depression, called PITTING EDEMA.Initially seen in areas with loose connective tissue such as periorbital area.

PULMONARY EDEMA:

Weight of the lungs is 2-3 times the normal weight. Edema fluid can be removed from the lungs by suction and can be blood-tinged with extravasated RBCs.

BRAIN EDEMA:

Gyri are distended ,flattened and sulci narrow.

Brain herniation can occur and when in the foramnen magnum area can cause compromise of the cardiopulmonary center with DEATH.

Edematous lung

Edematous lung parenchyma

Edematous white matter on the side of tumor