Edema - MBBS Students Club

• Excess fluid in the tissues
Intracellular Edema
Extracellular Edema
Intracellular Edema
1) Hyponatremia
(2) Depression of the metabolic systems of the
(3) Lack of adequate nutrition to the cells
4) Intracellular edema can also occur in inflamed
tissues. Inflammation usually increases cell
membrane permeability
Extracellular Edema
• Excess fluid accumulation in the extracellular
abnormal leakage of fluid from the plasma to
the interstitial spaces across the capillaries
 failure of the lymphatics to return fluid from
the interstitium back into the blood called
Capillary Filtration
Factors That Can Increase Capillary
• Increased capillary filtration coefficient
• Increased capillary hydrostatic pressure.
• Decreased plasma colloid osmotic pressure
I. Increased capillary pressure
I. Excessive kidney retention of salt and water
I. Acute or chronic kidney failure
II. Mineralocorticoid excess
II. High venous pressure and venous constriction
I. Heart failure
II. Venous obstruction
III.Failure of venous pumps
(a) Paralysis of muscles
(b) Immobilization of parts of the body
(c) Failure of venous valves
III.Decreased arteriolar resistance
I. Excessive body heat
II. Insufficiency of sympathetic nervous system
III.Vasodilator drugs
I. Decreased plasma proteins
a. Loss of proteins in urine (nephrotic syndrome)
b. Loss of protein from denuded skin areas
I. Burns
c. Failure to produce proteins
I. Liver disease (e.g., cirrhosis)
II.Serious protein or caloric malnutrition
I. Increased capillary permeability
I. Immune reactions that cause release of histamine
and other immune products
III.Bacterial infections
IV.Vitamin deficiency, especially vitamin C
V.Prolonged ischemia
I. Blockage of lymph return
I. Cancer
II.Infections (e.g., filaria nematodes)
IV.Congenital absence or abnormality of lymphatic
Safety Factors That Normally Prevent
(1) low compliance of the interstitium when
interstitial fluid pressure is in the negative
pressure range
(2) the ability of lymph flow to increase 10- to
(3) washdown of interstitial fluid protein
concentration which reduces interstitial fluid
colloid osmotic pressure
1.The safety factor caused by low tissue
compliance in the negative pressure range is
about 3 mm Hg.
2.The safety factor caused by increased lymph
flow is about 7 mm Hg.
3.The safety factor caused by washdown of
proteins from the interstitial spaces is about 7
mm Hg
• The total safety factor against edema is about
17 mm Hg
• This means that the capillary pressure in a
peripheral tissue could theoretically rise by 17
mm Hg before marked edema would occur

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