The below mentioned article provides a short note on Edema:- 1. Introduction to Edema 2. Clinical Manifestations of Edema 3. Management.
Introduction to Edema:
Edema is recognized by the increase in the volume of interstitial fluid.
There are three types:
a. Nephrotic Type:
This type is produced by the lowering of serum protein concentration due to severe albuminuria or to low protein intake. If the serum colloidal osmotic pressure drops below the normal, there is accumulation of interstitial fluid.
b. Nephritic Type:
This type is formed by damage to the capillary endothelium allowing the passage of protein into the interstitial fluid. The lowered osmotic pressure allows greater filtration and less reabsorption. This mechanism is applied in acute glomerulonephritis. Renal factors also play an important role in it.
c. Cardiac Edema:
Increased venous pressure produces cardiac edema. Many believe that renal retention of sodium produced by forward failure of heart leads to retention of water, to increased venous pressure and then to edema.
Clinical Manifestations of Edema:
a. Facial edema distinguishes nephritic or nephrotic edema from cardiac edema. The whole face becomes swollen. Patients with uremia often have such facial edema.
b. General dehydration of uremia usually minimizes the facial edema.
c. Edema of the brain has also been reported in acute glomerulonephritis.
d. Edema produced by ‘forward failure’ diminishes cardiac output and thereby decreases renal circulation. The lowering of glomerular filtration produces a greater re-absorption of sodium which, in turn, causes a greater reabsorption of water.
Management of Edema:
Diuresis is essentially an increase in urine output sufficient to produce a significant negative balance of water; and negative balance of water signifies negative balance of sodium.
In most edema, if glomerular filtration is not greatly diminished, diuresis can be established by sodium intake. The water intake need not be limited. Normal or even higher than normal ingestion of water may enhance the urine output. Such management is beneficial in cardiac, nephrotic and cirrhotic edema.
Two new powerful diuretics—Ethacrynic acid and Furosemide—have recently been introduced. Ethacrynic acid inhibits the reabsorption of sodium in proximal and distal segments. Furosemide produces a prompt excretion of water, sodium and chloride. Potassium injection is moderate. It inhibits reabsorption of sodium also.