When it comes to pitting edema, it involves evident indentation that is visible for some time after the release of pressure applied on the affected area. Edema is described as swelling triggered by the accumulation of unusually substantial amounts of fluid in the interstitial tissues which is the area adjacent the cells and blood vessels of the body.
It is a symptom rather a disease and can be triggered by systemic conditions that involves various organ systems or localized conditions that involves an area where the swelling occurs. The edema can occur all over the body as generalized swelling or it can affect only a specific region such as the lower extremities. Even though edema might be hard to detect in minor cases, larger areas of fluid build-up can be evident and palpable. It can present as either pitting or non-pitting edema.
Chronic venous insufficiency
The veins are responsible for returning blood to the heart from all the bodily tissues. The venous blood that returns from the legs should flow upward against gravity. The veins in the legs depends on the muscle pumping action of the calf and foot muscles to maintain enough return of blood to the heart.
With every contraction of these muscles, the blood within the veins is squeezed upwards. The one-way valves inside the veins ensure that the blood flows up and not back down. Chronic venous insufficiency develops once these valves are damaged, thus the veins dilate or the muscle pump action is insufficient which allows the blood to leak backwards. The additional fluid inside the veins causes a pooling outcome which forces the leakage of fluid into the interstitial tissues in the inferior extremities which results to pitting edema.
Pitting edema due to congestive heart failure
This condition occurs once the pumping action of the heart is disrupted. There are numerous causes such as diminished blood supply to the heart muscle, high blood pressure, coronary artery disease and heart valve disorders that might lead to the weakening of the heart muscle.
After some time, the heart could no longer keep up with the demands placed on it to drive blood into the arteries of the bodily systems and to receive blood that returns from the body in the veins. This can lead to a pooling effect of blood which leads to increased pressure inside the veins. The increased intravenous pressure will force leakage of the fluid into the interstitial tissues which causes pitting edema. Different parts of the body such as the feet, legs, organs and the abdomen can be affected by the swelling.
The kidneys are responsible for the removal of waste products and extra water from the body which are eliminated via urine. The removal of the waste products and excess water is managed by the nephrons inside the kidney which filter out these substances from the blood.
Various conditions such as high blood pressure, diabetes or toxic injury to the kidneys due to drugs can damage the nephrons which results to kidney disease. Certain kidney diseases such as nephrotic syndrome can lead to abnormal loss of proteins from the blood into the urine.
The water molecules adhere to the protein, thus adequate concentration of certain proteins in the blood is required to maintain fluid balance. Due to the abnormally low concentration of protein in the blood, the fluid leaks into the tissues which results to pitting edema.