Anasarca also known as generalized edema, is a medical condition that manifests in form of swelling of skin as a result of accumulation of fluid into extracellular space. It is caused by a number of conditions ranging from rental failure, liver failure, or right-sided heart failure. Edema is the term given to excessive fluid accumulation in spaces between cells (tissue spaces) or the interstitial space.
The accumulation of fluid may also occur in cavities of body but it does not include the fluids in bladder or the gastrointestinal tract. Edema may be found within a specific area or localized— where it affects only one part or organ of body. At times, it can be generalized meaning that it affects many parts of body or the entire body at the same time.
In the body, fluid exists within the cells or intracellular fluid. It also exists within spaces found between cells (tissue spaces). Fluid in body may be found within blood vessels and lymphatic vessels. Fluid within blood vessels is at a higher pressure than the fluid in the tissue spaces. This is due to the pumping heart that pushes the blood with force within the vessels.
Blood does not just filter out of the vessels unless the vessel wall becomes permeable and allows it to exit. Fluid within the tissue spaces also have a hydrostatic force but this is usually smaller than the pressure within the vessels so very little fluid flow from the tissues spaces into the vessel due to hydrostatic pressure.
Usually fluid from the tissue spaces enters the blood vessel due to a difference in osmotic pressure. In anasarca or generalized edema, fluid accumulates within subcutaneous tissue found in skin and this causes gross swelling of body. Edema occurs when capillary filtration exceeds the lymphatic drainage.
How edema occurs
Edema occurs in different situations. When there is increased hydrostatic pressure, it pushes fluids out of blood vessels into the tissue spaces. Another way in which edema occurs is by reduced osmotic pressure in vessels meaning that no fluid is pulled to blood vessels, therefore, it continues to accumulate in the tissue space.
Increased vascular permeability allows the walls of vessels to pass fluids out to tissue space and because the fluids in tissue space are not being drawn into vessels fast enough, there is increased amount of these fluids in the tissue space. A lymphatic obstruction causing the lymph vessels to block means that the interstitial fluid cannot drain properly from tissue spaces resulting in accumulation of the fluids into the tissue spaces.
A person with anasarca shows signs like general swelling of body. This is the most visible symptom. Other symptoms include pain in swollen areas and difficult urinating if the male genitals are affected.
Causes of anasarca
Many conditions cause edema whereby some lead to localized swelling and others result in generalized swelling as in case of anasarca. The causes may vary from heart and blood vessels to liver and kidney disease. Drugs may also be a culprit for generalized edema. Autoimmune disorders like lupus may be associated with anasarca.
The development of anasarca is an indicator of a severe and seriously illness, which often is in the stages of becoming a chronic disease. Anasarca or generalized edema isn’t a disease in itself but a symptom of another underlying condition. It can occur due to malnutrition, protein deficiency, administering of exogenous intravenous fluids, or chemotherapy drugs.
It is common in patients who have kidney and heart failure. When there is a cardiac problem accompanied by renal failure, it can cause edema and anasarca. Generalized edema or anasarca occurs in patients having kidney failure due to loss of protein in urine meaning the kidney is unable to function well. This causes water and other toxins to be retained in body.
When there is increased retention of toxins and water, swelling is likely to occur. A patient with heart failure experiences poor cardiac function meaning there is low amount of blood volume which is pumped by heart to other body parts. Due to this problem, the kidney is likely to sense that there is reduced blood volume in body. In order to compensate for the reduced volume, more water and salts are retained thereby resulting to edema.
Anasarca can occur due to salt intake. While in normal people, the salt in body may be regulated by being excreted in urine, when a patient has heart or kidney failure, salt should be limited to prevent retention of water. Another condition known as idiopathic edema, whose cause is not known but is associated with women in premenopausal period or those who use diuretic for an extended time, may be another possible cause for edema.
Diuretic themselves help reduce edema from urine excretion, however, a rebound phenomenon can occur. Leaks in capillaries can cause fluid to pass to interstitial space making the kidney to retain salt and water when it senses there is reduced blood volume.
Treatment of anasarca
Treatment of generalized edema or anasarca is aimed at addressing the condition causing the problem, and the symptoms such as pain. Loop diuretics may be administered to help in excreting the excess water that is retained in interstitial spaces. It is important to treat the underlying cause of anasarca. Medications may be administered to help treat renal failure. Congestive heart failure may also be treated to help reduce the accumulation of fluids in interstitial space.