Physiology, Symptoms, Diagnosis, and Treatment of Peripheral Edema

Some of us may have heard of the name David Goggins, and for people who do not know who he is, David Goggins is a former Navy SEAL, endurance athlete, fitness trainer and motivational speaker. In 2021, David showed a video of an Edema in his leg and that he had undergone surgery. The post today isn't about David, but about Edema. David was showing a swelling in his legs, and that explains in a shallow form what edema is.

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Edema is a swelling in the tissue of a patient, as a result of fluids being trapped in the tissue part of the body. According to an article on USGS, about 60% of a man's body is made up of water, which occur basically as, intracellular fluids and extracellular fluids. Extracellular fluids make up one third of the entire fluid in the body, while intracellular fluid makes up two-third of the fluid in the body. Extracellular fluids can be found in the Extravascular or Interstitial areas, and the Intravascular area. Intravascular plasma have a volume up to 25% while the extravascular or interstitial plasma have a volume of up to 75%. To explain Intracellular fluid, it is fluid inside the cell, while extracellular fluids are fluids that contain other materials such as nutrients and the cells themselves. Balancing fluid in the body is possible thanks to hydrostatic and oncotic pressures. When the heart pumps blood, it pumps at a very high pressure. As it moves, it exerts force on the walls of the vessels. As the blood moves to smaller vessels, the pressure reduces, in the capillaries, the force create a hydrostatic pressure, which allows for fluids to be pushed out of the vessels, causing an exchange of materials between the intravescular and the Interstitial area. Other factors that determines the balancing of fluids in the body are vessel wall permeability , as well as the lymphatic system.

It is important to know that several materials in the fluids do not get dissolved into the fluid, like the red blood cells, protein, and many others, and while they are distributed to the interstitial area, by the arteries, they return through the veins. Majority of the undissolved materials in the fluid remain in the interstitial area, after which they are collected by the lymphatic system. The lymphatic system filters the fluid after collecting them, and return them back to the veins, so they return back to the heart. With this, the body doesn't store fluid in the interstitial area. When the Lymphatic system cannot absorb fluid, filter them and return them back to the veins, thereby causing interstitial area to increase is known as Edema.

Edema can be caused by several reasons, which would include;

The Increase in the Capillary Hydrostatic Pressure.

Whatever factor that would cause an increase in the hydrostatic pressure causing excessive fluid to go into the interstatial area, would lead to edema. Cases of Hypertension would lead to increase in the pressure exerted on the capillaries, causing more fluid to go into the interstitial region, factors such as venous hypertension, right side heart failure could lead to increase in pressure of blood coming and nothing returning or reduced pressure in the returning of blood. Plasma volume increase as a result of factors such as pregnancy, or using drugs, would also affect the increase of capillary hydrostatic pressure.

Decrease Oncotic Pressure of fluid.

Oncotic pressure is the osmotic pressure that allows for fluid to leave the interstitial area back to the intravascular area. This is usually spareheaded by protein albumin. The liver is responsible for producing albumin, when there is a reduction in the amount of albumin in the interstitial area, usually a level below 2 g/dl, an Edema could occur. This can be as a result of conditions such as liver failure, eclampsia, Renal diseases, Vitamin deficiencies, other hepatic diseases, and other factors that could lead to protein loss will lead to a decrease in the oncotic pressure of fluid.

The Integrity of the Cappilary endothelial wall

A damage in the wall of the capillary can cause Edema, as fluid will lack the oncotic pressure to return back to the intravascular area. Factors that could lead to a damaged capillary are vascular injuries (from surgery), Burns, Inflammation, Cellulitis, Production of histamine to dilate the blood vessel causing fluid to rush into the capillary.

Obstruction in the Lymphatic System

An obstruction to the lymphatic system would prevent the system from collecting fluid and proteins from the interstitial area, filtering the protein and sending the fluid back to the vein. This would cause Edema, and conditions such as lymphedema, tumor, and Filariasis can be responsible.

Symptoms, Diagnosis and Treatment

Edema could cause acute swelling of the limbs, and other interstitial area of the body. The area becomes larger in about 24 to 48 hours, the swollen area become stretched, with difficulty in moving the area, as well as discomfort in the region.

Diagnosis of Edema would include the pitting test, where the medical practitioner place their finger on the swollen region to create a dimple on the region.

Treatment of Edema starts with treating the underlying condition that causes it, such in cases of lung diseases, heart failure, and other vascular diseases, the disease are treated first. To help reduce the swelling, the patients are advice to cut down of sodium contents (salt), and the use of diuretics to get rid of the fluid