Edema (aka hydropsy) is an abnormal accumulation of fluid in the interstitium, located beneath the skin and in cavities of the body which cause severe pain. It manifests as swelling.

• The amount of interstitial fluid is determined by the balance of fluid homeostasis, and the increased secretion of fluid into the interstitium, or the impaired removal of the fluid can cause edema
• It is caused by inability of this fluid to be removed by normal processes

• Pitting edema is where indentation persists after release of a pressure. It results from water retention
• Sacral edema is palpated at the lower back, and is associated with heart failure

Source: OSCE Skills

• Anasarca (aka extreme generalized edema) involves widespread swelling of the skin, due to effusion of fluid into the extracellular space. It is usually caused by liver failure (cirrhosis of the liver), renal failure/disease, right sided heart failure, as well as severe malnutrition/protein deficiency. The increase in salt and water retention caused by low cardiac output can also result in anasarca as a long term maladaptive response

• Increased hydrostatic pressure, including:
  • Heart failure
• Decreased osmotic pressure, including:
  • Nephrotic syndrome
  • Liver failure

• Peripheral edema