Anasarca

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Anasarca
Anasarca

Anasarca Definition

By definition, Anasarca is the gross and generalized edema of the body tissues with profound subcutaneous swelling. [1]   So, what is edema? Edema is the bloating up of any body part due to accumulation of excess fluid in the body tissue.

When this edema is confined to a particular part, say in a twisted ankle, it’s called localized edema. When this bloating involves the whole body and appears like an inflated balloon , it is known as Anasarca which is derived from the Greek phrase ‘ anà ‘ meaning ‘through’ and ‘sarx’ meaning ‘flesh ‘.[2]

 

Pathophysiology of Anasarca

As Anasarca is the gradual progression of the swelling, the pathophysiology of Anasarca is the same as that of edema, only for a longer duration and with more severity.

To understand the mechanism, one should know a few relevant facts. About 60% of our lean body weight is made up of water of which two third lies within the cells (40%) and one third lies outside the cells (20%). The extracellular fluid can be divided into Interstitial fluid, the fluid that lies in between the cells (IF -15% – about 10.5 l) and plasma fluid which lies within the blood vessels (5% – about 5 l) [3].  Accumulation of excess fluid in the interstitial space between the tissues causes edema.

extracellular and intracellular compartments anasarca image

This can occur due to

Abnormal leak of plasma fluid to interstitial space

  • Increased hydrostatic pressure
  • Reduced plasma osmotic pressure
  • Sodium Retention

Failure of lymphatic vessels to return excess fluid from interstitium to plasma.

  • Lymphatic obstruction
  • Major surgery
  • Some cancers

Of the factors above, Lymphatic obstruction usually causes localized edema of the part which is drained by the obstructed lymphatic vessel and the factors severe enough to cause Anasarca are :

Increased hydrostatic pressure

The blood lies in blood vessel which is like a pipe which allows fluid and some substances to pass through its walls and reach the tissue nearby. Hydrostatic pressure is the effort of the fluid in the blood vessel to escape into the surrounding tissue. Hence, when there is more fluid in the vessel, it exerts more pressure to leak into the surrounding. This happens mostly due to venous stasis, in which the blood flow slows down and pools in a region. Thus all conditions causing venous stasis will cause edema which when not relieved will lead to Anasarca.

Reduced colloid osmotic pressure

Similar to the force exerted by magnets on iron dust, the plasma proteins exert the colloid osmotic pressure that is responsible for retention of fluid within the blood vessel. Albumin is the major contributor of colloid osmotic pressure. When there is a gross decrease in plasma proteins either due to reduced synthesis or increased loss, it leads to profound fluid leak into the interstitial space.

Sodium Retention

Kidney is the major organ for regulating the concentration of various salts in our body of which, the most important are sodium and potassium. When there are more electrolytes, the kidney removes them in urine and when there is low electrolyte level, it retains the salts to balance them to normal. When there is a kidney disease, this function is affected.

Excess of Sodium or Salt is retained which in turn causes water retention. This leads to more fluid in the blood causing intravascular volume expansion which in turn increases the hydrostatic pressure. Also, the increased intravascular fluid volume leads to dilution of the plasma proteins causing reduction in the colloid osmotic pressure. Thus sodium retention involves both the mechanisms. [1]

Causes of Anasarca

Increased hydrostatic pressure

Impaired venous outflow

  • Congestive heart failure
  • Constrictive pericarditis
  • Liver cirrhosis
  • Venous obstruction due to large tumors

Arteriolar dilatation

  • Neurohumoral dysregulation

Reduced osmotic pressure

Reduced protein intake

  • Protein malnutrition – Kwashiorkor
  • Starvation

Reduced protein synthesis

  • Liver cirrhosis

Increased excretion of protein

  • Protein losing glomerulopathies – Nephrotic  syndrome
  • Protein losing enteropathy

Sodium retention

  • Increased salt intake with renal insufficiency
  • Increased reabsorption of sodium
  • Increased rennin- angiotensin – aldosterone mechanism
  • Mineralocorticoid excess

Some drugs

like anabolic steroids, steroids like prednisolone [1] [4][5]

Anasarca in heart failure

Congestive heart failure or right heart failure is the most common and most serious cause of Anasarca. [4]As correctly said, Heart is a pump that pushes the blood throughout the body. The circulated blood again reaches the heart and the cycle continues. When the heart fails to pump, the circulated blood (venous blood) is slowed down from pumped again leading to venous stasis.

As said above, it leads to increased hydrostatic pressure and edema. The edema begins in the most dependent part initially – feet and ankle- and then becomes a full blown Anasarca when the heart’s function has deteriorated to great extent.

Anasarca in heart failure photo

Anasarca in Nephrotic syndrome

Nephrotic syndrome is a kidney disease of children in which the sieve like glomerular membrane become leaky to the plasma proteins like albumin. So a large amount of albumin is lost in urine which lowers the colloid osmotic pressure.  Initially the edema begins in loose tissues around the eyes giving a puffy eye appearance which then gradually progress to Anasarca when the plasma protein level falls below 2.5 gm/100ml which is less than one third of normal level. [6]

Other kidney diseases affect the excretion of sodium and water which leads to excessive intravascular fluid volume leading to edema.

Anasarca in Liver diseases

The most common liver disease causing Anasarca is Liver cirrhosis. Liver is the factory manufacturing the plasma proteins. When the functional parenchymal cells, the workers of liver get replaced by useless fibrous tissue, it leads to low protein production. This leads to low osmotic pressure and fluid leak to the interstitium. Another mechanism is that, fibrous scar in the liver compress the portal vessels which pass through the liver, leading to increased hydrostatic pressure in the veins of abdominal organs. This leads to accumulation of fluid in peritoneal cavities which is known as hydroperitonium or Ascites.

Anasarca picture
Anasarca

Picture 1: Anasarca (abdomen)

Image Source: expression.psmalik.com

Anasarca in Children

The major cause of Anasarca in children is protein energy malnutrition – Kwashiorkor in which the protein deficiency is more severe than energy malnutrition. It is most commonly seen in children of 1-4yrs of the impoverished Southeast Asian countries and African children are who are weaned early. [7]

Rarely, premature infants develop hypoprotenemic edema due to immature liver which doesn’t produce the sufficient plasma proteins.

Anasarca image

Picture 2: Anasarca in a Child

Image source: en.wikipedia.org

Anasarca photo

Differential Diagnosis of Anasarca

  • Congestive heart failure
  • Heart failure due to cardiac cirrhosis
  • Heart failure due to thiamine deficiency
  • Alcoholic liver cirrhosis
  • Nephrotic syndrome
  • Malnutrition / starvation
  • Kwashiorkor
  • Kwashiorkor like syndrome in severe trauma and burns
  • Hypoalbuminemia/ hypoprotenemia
  • Protein losing enteropathy
  • Eclampsia in pregnancy
  • Hypothyroidism

Treatment of Anasarca

Anasarca is not a disease but a symptom indicating a serious underlying derangement. So treatment of the underlying cause will resolve Anasarca. When Anasarca is caused by fluid overload, diuretics are the choice. When it is due to protein deficiency, albumin infusion can be tried. And every cause of Anasarca has its own treatment protocol. [8]

References

  1.    Robbins and Kotran 7/e pg 120- 121
  2.     www.merriam-webster.com/dictionary/anasarca
  3.     Ganong 22/e pg 1
  4.     Guyton 11/e pg 303
  5.     Wikipedia
  6.     O.P.Ghai 7/e pg 450
  7.     O.P.Ghai 7/e pg 67
  8.     http://www.webmd.com/heart-disease/heart-failure/edema-overview

4 COMMENTS

  1. I have been reading up on a lot of medical conditions and how the body works. I have never actually heard of Anasarca, likely because it seems to effect people mostly in 3rd world countries where starvation is a huge issue. Also, an issue with the liver makes me believe that it can be caused by alcoholism. Is that true?

    • It can be yes. There are several things that can trigger this but malnutrition is the biggest one form my understanding. I read an article not too long ago that actually spoke about people who are overweight and even obese being malnourished. The new face of malnourished is not someone who is skin and bones, but 300+ pounds.

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