Lymphology Association of North America (LANA) Practice Exam

What factor can contribute to the formation of edema?

1. Decreased plasma proteins

2. Increased capillary permeability

3. Increased capillary filtration

4. All are true

The correct answer is: All are true

Edema refers to the swelling caused by excess fluid trapped in the body's tissues. Various factors can contribute to the formation of edema, and understanding each one plays a crucial role in recognizing how fluid balance is maintained in the body. Decreased plasma proteins can significantly affect oncotic pressure, which helps to retain fluid within the blood vessels. When plasma proteins, such as albumin, are low, there is a decrease in the ability to hold fluid in the vascular space, leading to the transudation of fluid into the interstitial spaces and resulting in edema. Increased capillary permeability allows larger molecules and proteins to pass through the capillary walls more easily. This alteration can occur due to inflammation, infection, or injury. When capillaries become more permeable, fluid and proteins leak out into the surrounding tissue, contributing further to edema formation. Increased capillary filtration happens when the pressure within the capillaries rises, pushing more fluid out into the interstitial spaces. This can occur in conditions such as heart failure, where increased pressure in the venous system causes fluid to seep out into the surrounding tissue. Each of these factors—decreased plasma proteins, increased capillary permeability, and increased capillary filtration—can independently contribute to the development