Edema - Nephritis

Edema (swelling) is one basic clinical manifestation of nephritis and there are about half patients will have edema when they have the symptom of oliguria. Often the edema will first appear in loose places such as eyelid, face and scrotum and then it will involve the lower limbs and then the whole body and a few cases may even have ascites.

Why there is edema in nephritis:

1. The renal filtration area will decrease and the permeability will be lowered the blood flow in kidneys is reduced while the re-absorption ability of renal tubules is normal resulting in oliguria.

2. The immune damages cause increased permeability of the capillary wall and cause fluid in the plasma to flow into tissue space.

3. Long term loss of large amount protein in urine will cause hypoalbuminemia and lower the plasma colloid osmotic pressure. The extracellular fluid will be held up in the tissue space.

4. Decreased blood flow and ischemia will stimulate more secretion of aldosterone and increase the re-absorption of water and sodium.

In a word, in case of nephritis, the glomerular filtration rate (GFR) is reduced, renal intrinsic cells are damaged and renal fibrosis is started, therefore the key point to relieve edema and treat nephritis is to block the process of renal fibrosis.