edema

Edema is the accumulation of fluid in tissues. It is caused by an imbalance between forces holding fluids in the vasculature and tissues. Fluids are normally held in a steady state between tissues and vasculature by homeostasis between these forces (Starling equation) :

• capillary hydrostatic pressure - drives fluid out of the vasculature into tissues
• plasma colloid osmotic pressure - keeps fluid in the vasculature, preventing extravasation into the tissues
• tissue colloid osmotic pressure - keeps fluid in the tissues

Clinical presentation

• peripheral edema
  • pitting edema
  • anasarca
  • myxedema
• pulmonary edema
• pleural effusions
• ascites

Pathology

Etiology

• increased capillary hydrostatic pressure
  • congestive cardiac failure
  • venous obstruction, compression, or thrombosis
  • ascites
  • constrictive pericarditis
  • arteriolar dilatation
• reduced plasma colloid osmotic pressure
  • ascites and liver cirrhosis
  • nephrotic syndrome
  • malnutrition 
  • protein-losing enteropathy
• increased tissue colloid osmotic pressure
• increased vascular permeability
  • inflammation
  • infection
• reduced lymphatic clearance
  • lymphedema
  • lymphatic obstruction
• increased salt retention (causes both increased hydrostatic pressure and reduced plasma colloid osmotic pressure by fluid retention)
  • renal insufficiency

Siehe auch:

• Hirnödem
• radiologischer Ödemindex

und weiter:

• emergency CT head (mnemonic)
• Fogging Phänomen CT
• Anasarka
• Fogging Phänomen