Anasarca · What Is It, Causes, Signs, Symptoms, and More

Anasarca is a form of extreme, generalized edema, which is when fluid accumulation causes a palpable swelling throughout the entire body.  

Edema occurs when there are changes in one of the two forces that determine fluid movement across capillary walls: hydrostatic pressure and oncotic pressure. Capillary hydrostatic pressure causes fluid to flow from the capillaries and into the interstitial space, or the space between cells; whereas capillary oncotic pressure draws this fluid back into the capillary. Oncotic pressure is a type of pressure exerted by the cells and proteins present in blood, like albumin, which is produced in the liver. When taking into account these two forces, only a very small amount of fluid leaks into the interstitial space, and that fluid is typically picked up by the capillaries of the lymphatic system.  

Anasarca arises from disorders that cause an imbalance between hydrostatic and oncotic pressure, causing more fluid to leak from the capillaries into the interstitial space. Hydrostatic pressure can increase in cases of heart and kidney failure as well as in cases of venous obstruction.  

On the other hand, oncotic pressure decreases when there’s a low concentration of albumin in the blood, called hypoalbuminemia. This can happen when the production of albumin is decreased, like in cases of liver cirrhosis as well as with nephrotic syndrome where albumin and other proteins are lost in the urine. Other causes of anasarca include burns, trauma, and malignancy: all of which increase capillary permeability, thereby allowing more fluid to leak from the capillaries. On top of that, hypoalbuminemia can arise in cases of severe malnutrition, particularly protein-energy malnutrition (e.g., Kwashiorkor), where the body doesn’t receive enough of the nutrients required to produce albumin.  

 Although rare, anasarca can be a side effect of certain medications, including steroids and calcium channel blockers (e.g., amlodipine).  

The treatment of anasarca focuses on addressing the underlying cause when possible. For example, in cases where anasarca is caused by heart failure, treatment may include diuretic medications, including furosemide (i.e., loop diuretic) and spironolactone (i.e., potassium-sparing diuretic) as well as vasodilator medications, like ACE inhibitors. These medications cause dilation of the blood vessels, making it easier for fluid to return to the capillaries. 

In cases of end-stage renal failure, individuals may require dialysis to help remove excess fluid from the body. Similarly, individuals with cirrhosis may undergo therapeutic paracentesis, which is a procedure used to remove fluid from the peritoneal cavity. Finally, all individuals may be encouraged lifestyle modifications, such as salt restriction to help prevent further fluid accumulation. 

Individuals undergoing treatment of anasarca may lose up to 2-3 liters of fluid in a 24-hour period due to the excess fluid accumulation.