What causes systemic edema?

Sometimes, after we drink some water before going to bed the night before, our face will be swollen when we wake up the next morning. Therefore, edema is a condition that we often encounter in life. Some people have edema all over their body. This is a symptom caused by disease. When the human body takes in too much water or excretes too little water, the water in the body will increase, the weight will increase, and then the air tissues and organs will swell, which is usually called edema or water poisoning. Common causes of edema may include decreased plasma protein concentration or congestive heart failure, which increases fluid accumulation in the body and causes edema. After edema occurs, due to different changes in plasma osmotic pressure, the total amount can be divided into hyperosmotic, isotonic and hypoosmotic edema. So what are the causes of swelling all over the body?

1. Cause/edema

(1) Systemic edema: common in right heart failure, pericardial disease, various types of nephritis and kidney disease, decompensated cirrhosis, chronic wasting disease, long-term nutritional deficiency, vitamin B1 deficiency, myxedema, drug-induced edema, etc.

(2) Local edema: common in local inflammation, limb vein thrombosis and thrombophlebitis, superior or inferior vena cava obstruction syndrome, elephantiasis caused by filariasis, etc.

2. Mechanism/edema

In a normal human body, the fluid in the blood vessels is constantly filtered out from the arteriolar end of the capillaries into the interstitial space to become tissue fluid. On the other hand, the tissue fluid is constantly absorbed back into the blood vessels from the venous end of the capillaries. The two often maintain a dynamic balance, so there is no excessive fluid accumulation in the interstitial space.

3. The main factors to maintain this balance are :

(1) Hydrostatic pressure in capillaries;

(2) plasma colloid osmotic pressure;

(3) mechanical pressure in the tissue space (tissue pressure);

(4) Colloidal osmotic pressure of tissue fluid. If the factors that maintain fluid balance are disturbed, edema may occur.

4. Several main factors that cause edema are:

(1) Sodium and water retention: such as secondary aldosteronism;

(2) Increased capillary filtration pressure: such as right heart failure;

(3) Increased capillary permeability: such as acute nephritis;

(4) Decreased plasma colloid osmotic pressure: usually secondary to a decrease in serum protein, such as chronic nephritis, nephrotic syndrome, etc.